Search

To evade legal controls, new psychoactive substances (NPS), which have been designed as substitutes for traditional and synthetic drugs, are gradually dominating the drug market. Synthetic cannabinoids (SCs), which account for the majority of NPS, are rapidly being derivatized; consequently, controlling increasing abuse by merely listing individual compounds is difficult. Therefore, China has included the entire SC category of SCs listed as legal controlled substances since July 1, 2021. However, new SCs obtained through structural modification are still appearing and pose significant analytical challenges for forensic laboratories. Therefore, an efficient, green, and automated detection method is urgently required to provide technical support for the accurate screening actual samples. Meanwhile, the number of indazole-type SCs has increased sharply since 2013, which is ascribable to their stronger psychoactive effects. Indeed, forensic laboratories mainly analyze this key SC subclass. Therefore, in this study, we developed a new method for analyzing 51 indazole-type SCs in human urine and blood, which involves online solid-phase extraction (online SPE) as the preprocessing technology, with analysis performed using liquid chromatography-linear ion trap mass spectrometry. Deproteinization was achieved by adding acetonitrile, with dilution performed using 10 mmol/L ammonium acetate solution (pH 4.8) containing 0.1% formic acid. Samples were then analyzed directly using acetonitrile-10 mmol/L ammonium acetate aqueous solution (containing 0.1% formic acid) as the mobile phase. The mass-to-charge ratios of protonated molecular ions ([M+H] + ) in the mass spectra acquired in full-scan mode, and the retention times in the chromatograms of the analytes were selected with the aim of monitoring the MS 2 ions of the various compounds. Characteristic fragment ions of the various SC structures were summarized, with five groups of isomers, each containing ten compounds, successfully distinguished using multistage mass spectrometry and their retention times. Multistage MS was used to qualitatively screen 51 indazole-type SCs, which were then quantitatively analyzed using MS 2 ion pairs (as quantitative ion pairs). The analytes exhibited limits of detection (LODs) of 0.02-1 ng/mL, with limits of quantification (LOQs) of 0.04-4 and 0.1-4 ng/mL in urine and blood, respectively. Linear fitting (weighting factor 1/ x ) revealed good linearity for each analyte within its respective linear range, with correlation coefficients ( R 2 ) greater than 0.99 in both urine and blood. The validity of the analytical method was tested by determining precision and spiked recovery values ( n =6). Recoveries of 83.47%-116.95% were obtained at LOQ levels, with precisions of 2.29%-13.40%. In addition, recoveries of 86.63%-113.38% and precisions of 0.58%-13.79% were obtained at low, medium, and high levels. The method described herein is not only easy to operate but also can be automated. Indeed, high-throughput sample analysis was achieved when sample extraction, enrichment, and analysis were performed in dynamic mode through valve switching. Meanwhile, the method exhibited good sensitivity and is applicable to a wider range of compounds than those previously reported; it also provides a scientific basis and technical support for the rapid screening and quantitative analysis of SCs in actual relevant cases.

Objectives: To develop a two-dimensional liquid chromatography method to determine the content of vitamin D 3 in cod liver oil preparations., Methods: The samples were prepared by saponification and extraction, and the content of vitamin D 3 was determined by two-dimensional liquid chromatography with dual-pump-single-valve switching dual detectors. The chromatographic column, capture device, and detection wavelength were optimized; the linearity, system suitability, recovery rate, repeatability and sample stability of the method were investigated, and further validated in actual sample determination., Results: A column switching two-dimensional chromatography method was developed. In the first chromatography dimension, an Agilent PoroShell SB-C8 (50 mm×4.6 mm, 2.7 μm) column was used with acetonitrile-water as the mobile phase with gradient elution at a flow rate of 1.0 mL/min and detection wavelength as 264 nm. An Agilent Zorbax SB-C18 (150 mm×3.0 mm,1.8 μm) column was used in the second chromatography dimension with acetonitrile as the mobile phase at a flow rate of 0.42 mL/min, and detection wavelength as 264 nm. In determining vitamin D 3 content, there was a good linear relationship in the concentration range. The system suitability, recovery rate, repeatability and sample stability all met verification requirements., Conclusions: The two-dimensional liquid chromatography method developed in this study is accurate, reproducible and simple, and can simultaneously separate pre-vitamin D 3 , trans-vitamin D 3 , vitamin D 3 , and tachysterol D 3 .

Objective: To investigate vitamin D levels and the effect of exogenous vitamin D supplementation in the first trimester among pregnant women in our center. Methods: This was a prospective cohort study. A total of 98 women in the first trimester who were followed-up regularly in Peking Union Medical College Hospital from December 1 st 2020 to December 1 st 2021 were enrolled. Subjects who had medical conditions that affect vitamin D absorption or metabolism were excluded. Questionnaires were administered, and 25-hydroxyvitamin D [25(OH)D] levels were detected using liquid chromatography tandem mass spectrometry (LC/MS/MS) method. According to the basic 25(OH)D level, different dosages of exogenous vitamin D were supplemented. After 4 weeks, 25(OH)D levels were detected again to evaluate the effect of supplementation. T test, analysis of variance, χ 2 test, and multiple linear regression analysis were used for analysis. Results: The mean age of enrolled subjects was (33.5±4.0) years. The baseline 25(OH)D level was (41.2±20.0) nmol/L. Briefly, 70.4% (69/98) subjects were deficient in vitamin D, and 42.9% (42/98) patients were using vitamin D supplementation at the time of 25(OH)D testing. Single-factor analysis showed that vitamin D supplementation ( t =-4.21, P <0.001), season ( t =2.59, P =0.011), and nut-eating frequency ( t =2.67, P =0.009) were related to 25(OH)D levels. Multiple linear regression analysis showed that only vitamin D supplementation had a relationship with 25(OH)D level ( B =13.84, P= 0.006). According to the baseline 25(OH)D level, 400-5 000 U/d vitamin D3 was supplemented regularly for (4.1±2.5) weeks, and 25(OH)D levels significantly increased after supplementation [(64.1±18.1) vs (37.3±16.6) nmol/L, t =-9.36, P <0.001]. The ascending range was negatively associated with basic 25(OH)D level ( B =-0.66, P <0.001) and positively associated with supplementary dosage ( B =0.51, P <0.001). 25(OH)D levels increased by 0.51 nmol/L on average per 1 μg (40 U) of vitamin D supplementation daily. Conclusions: The proportion of vitamin D deficiency was high in the first trimester among pregnant women in our center. Exogenous vitamin D supplementation could significantly increase 25(OH)D levels, and the effect was negatively associated with basic 25(OH)D level but positively associated with supplementary dosage.

A liquid chromatography-tandem mass spectrometry method was established and validated for determining the concentrations of costunolide(CO), piperine(PI), agarotetrol(AG), glycyrrhizic acid(GL), vanillic acid(VA), and glycyrrhetinic acid(GA) in rat plasma. This method was then applied to the toxicokinetic study of these six compounds in rats with chronic cerebral ischemia(CCI) following multiple oral doses of Zhachong Shisanwei Pills. Finally, the effects of continuous multiple-dose administration of Zhachong Shisanwei Pills on the liver of CCI rats were investigated. The results showed that after oral administration of different doses of Zhachong Shisanwei Pills, the in vivo exposure of AG, VA, and GA was relatively high, with AUC&#95;(0-∞) values ranging from 604.0-2 494.2, 1 305.4-4 634.5, and 2 177.5-4 045.7 h·ng·mL~(-1), respectively, while the exposure of CO, PI, and GL was relatively low, with AUC&#95;(0-∞) values ranging from 37.8-238.2, 2.4-17.0, and 146.9-408.5 h·ng·mL~(-1), respectively. The C&#95;(max) and AUC&#95;(0-∞) of the six compounds were positively correlated with the administered dose. The T&#95;(max) of PI and AG ranged from 0.3 to 2.0 h, their T&#95;(1/2) ranged from 0.8 to 2.9 h, and their mean residence time(MRT) ranged from 1.0 to 3.7 h. The T&#95;(max) of GL and VA was shorter(0.4-1.9 h), while their T&#95;(1/2)(2.6-5.9 h) and MRT(2.5-8.5 h) were longer. Both CO and GA exhibited a bimodal phenomenon, with T&#95;(max) ranging from 1.6 to 6.6 h, T&#95;(1/2) ranging from 2.8 to 7.7 h, and MRT ranging from 4.1 to 12.9 h. Liver histopathology after 28 days of continuous multiple-dose administration of Zhachong Shisanwei Pills showed that the liver tissue remained normal at a low dose(crude drug 0.8 g·kg~(-1), approximately 5 times the clinical equivalent dose). However, as the dose increased(crude drug 1.1-3.0 g·kg~(-1), 6.9-18.8 times the clinical equivalent dose), varying degrees of liver damage were observed. Blood biochemical tests revealed no significant changes in the serum levels of alanine aminotransferase(ALT), aspartate aminotransferase(AST), alkaline phosphatase(ALP), and total bile acid(TBA) in CCI rats from administration groups 1 to 3(crude drug 0.8, 1.1, 1.5 g·kg~(-1)). However, ALT, AST, ALP, and TBA levels in groups 4 and 5(crude drug 2.1, 3.0 g·kg~(-1)) showed significant increases. This study preliminarily elucidated the toxicokinetic characteristics of the six compounds in Zhachong Shisanwei Pills and their effects on liver tissue in CCI rats, providing data as a reference for clinical use.

Therapeutic drug monitoring is a good interpretation of personalized medicine, which helps to improve the safety and effectiveness of patient medication. Liquid chromatography-tandem mass spectrometry (LC-MS/MS) has gradually been widely accepted by clinical laboratories due to its characteristics of specificity, sensitivity, and flexibility in method development. This article introduces the importance and analytical techniques for therapeutic drug monitoring, describes the application and development of liquid chromatography tandem mass spectrometry for therapeutic drug monitoring, new advances in the detection of different drug types and sample types, and challenges in automation, convenience, and standardization.

Synthetic cannabinoids (SCs), which are among the most widely abused new psychoactive substances, are much more potent and have greater efficacy than natural cannabis. SCs can be disguised in various ways and are commonly sold in the form of electronic cigarette oil. SCs belong to a large family with structures consisting of a core with substituents, linker, ring with substituents, and tail. New SCs can be developed by adding substituents, such as halogen, alkyl, and alkoxy groups, to the aromatic ring system or by changing the alkyl chain length. Since the emergence of so-called first-generation SCs, subsequent developments have led to eighth-generation indole/indazole amide-based SCs. As of July 1, 2021, the entire category of SCs was added to the list of controlled substances, but implementation requires urgent improvements in detection technologies. Typically, each method is limited to a few SCs. Owing to the vast number of chemically diverse SCs and their fast update speed, the determination and identification of various types of SCs using a single method is challenging. Therefore, rapid, sensitive, and accurate quantitative methods that includes various types of SCs must be developed to meet the demand for the qualitative and quantitative analysis of new SCs in seized electronic cigarette oil. In this study, a liquid chromatography-tandem mass spectrometry (LC-MS/MS) method was developed for the simultaneous determination of 102 SCs in electronic cigarette oil. The mass spectrometry and liquid-phase conditions influencing SC separation and determination were optimized. Using the external standard method, 102 SCs were successfully identified in electronic cigarette oil. The samples were extracted using methanol. Target analytes were separated on a Shimadzu Shim-pack GIST-HP C18 AQ column (100 mm×2.1 mm, 1.9 μm) at a column temperature of 40 ℃. The mobile phases consisted of (A) 0.1% formic acid aqueous solution and (B) methanol-acetonitrile (1∶1, v/v). The gradient elution conditions were as follows: 0-8 min, 55%A-15%A; 8-15 min, 15%A; 15-16 min, 15%A-55%A; 16-18 min, 55%A. The flow rate was 0.4 mL/min and the injection volume was 1 μL. Operating in the multiple reaction monitoring mode, the 102 SCs were identified within 18 min. Each SC exhibited a good linear relationship in the range of 1-100.0 μg/L with a correlation coefficient ( r )≥0.9915. The limits of detection were 0.01-0.30 μg/L and the limits of quantification were 0.04-0.99 μg/L, which meet the requirements for analyzing SCs in actual samples. Precision was determined using standard solutions with 2, 10, and 50 μg/L of the SCs. The precisions ( n =6) were 0.3%-6.0%. The recoveries of the 102 SCs, as evaluated by spiking electronic cigarette oil at low (2 μg/mL), medium (10 μg/mL), and high (50 μg/mL) levels, were 80.1%-119.8%. Good performance was observed for the analysis of real samples. The developed method is accurate, rapid, sensitive, and effective for the determination of the 102 SCs in electronic cigarette oil, satisfying the requirements for practical qualitative and quantitative analysis.

Neonicotinoid pesticides are a relatively new class of pesticides that have garnered significant attention owing to their potential ecological risks to nontarget organisms. A method combining solid phase extraction with liquid chromatography-tandem mass spectrometry (SPE-LC-MS/MS) was developed for the rapid and accurate detection of eight neonicotinoid pesticides (dinotefuran, E -nitenpyram, thiamethoxam, clothianidin, imidacloprid, imidaclothiz, acetamiprid, and thiacloprid) in wastewater. The chromatographic mobile phase and MS parameters were selected, and a single-factor method was used to determine the optimal column type, extraction volume, sample loading speed, and pH for SPE. The optimal parameters were as follows: column type, HLB column (500 mg/6 mL); sample extraction volume, 500 mL; sample loading speed, 10 mL/min; and sample pH, 6-8. The matrix effects of the wastewater samples were reduced by optimizing the chromatographic gradient-elution program, examining the dilution factor of the samples, and using the isotope internal standard calibration method. Prior to analysis, the wastewater samples were diluted 5-fold with ultrapure water for pretreatment. Subsequently, 2 mmol/L ammonium acetate aqueous solution containing 0.1% (v/v) formic acid and methanol was used as mobile phases for gradient elution on a ZORBAX Eclipse Plus C18 column (100 mm×2.1 mm, 1.8 μm). The samples were quantified using positive-ion multiple reaction monitoring (MRM) mode for 10 min. Imidacloprid-d4 was used as the isotope internal standard. The SPE process was further optimized by applying response surface methodology to select the type and mass of rinsing and elution solvents. The optimal pretreatment of the SPE column included rinsing with 10% methanol aqueous solution and elution with methanol-acetonitrile (1∶1, v/v) mixture (7 mL). The eight neonicotinoid pesticides showed satisfactory linearity within the relevant range, with linear correlation coefficients ( r ) all greater than 0.9990. The method detection limits (MDLs) ranged from 0.2 to 1.2 ng/L, and the method quantification limits (MQLs) ranged from 0.8 to 4.8 ng/L. The average recoveries of the eight neonicotinoid pesticides were in the range of 82.6%-94.2% at three spiked levels, with relative standard deviations (RSDs) ranging from 3.9% to 9.4%. Finally, the optimized method was successfully applied to analyze wastewater samples collected from four sewage treatment plants. The results indicated that the eight neonicotinoid pesticides could be generally detected at concentrations ranging from not detected (ND) to 256 ng/L. The developed method has a low MDL and high accuracy, rendering it a suitable choice for the trace detection of the eight neonicotinoid pesticides in wastewater when compared with other similar methods. The proposed method can be utilized to monitor the environmental impact and assess the potential risks of neonicotinoid pesticides in wastewater, thus promoting the protection of nontarget organisms and the sustainable use of these pesticides in agriculture.

Bisphenols (BPs) and parabens (PBs) are of great concern for environmental pollution and human health because of their endocrine-disrupting effects and potential health hazards. Urinary biomonitoring of BPs and PBs can provide basic data for human internal exposure evaluation, which is a prerequisite for accurately assessing their health risks. In this study, we developed a new pretreatment procedure based on solid supported liquid-liquid extraction (SLE) for the simultaneous separation of ten BPs and five PBs in human urine, followed by high performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS) analysis. In the instrumental analysis, the HPLC conditions and MS/MS parameters were comprehensively optimized. Accurate qualitative and quantitative determination of ten BPs and five PBs was achieved by introducing a ternary gradient elution system of water, methanol, and acetonitrile for LC separation. During sample pretreatment, the extraction solvent and elution volume were optimized. Specifically, urine samples were held at room temperature and centrifuged at 3000 r/min for 10 min. The supernatant (2 mL) was then transferred to a glass tube, and the pH was adjusted to 5.0 using HCl (0.5 mL; 0.1 mol/L) and NaAc-HAc buffer (1.5 mL). Thereafter, β -glucuronidase-arylsulfatase (20 μL) and surrogate standard solutions (10 ng; 13 C 12 -BPS, 13 C 12 -BPAF, 13 C 6 -MeP, and 13 C 6 -BuP) were added, and the mixture was incubated in a shaker bath in the dark at 37 ℃ for 16 h. After incubation, the hydrolyzed sample (4 mL) was loaded onto an SLE cartridge and equilibrated for a minimum of 5 min to ensure the solution was completely absorbed by the packing material. Subsequently, the target chemicals were eluted with a mixed ethyl acetate/ n -hexane solution (3∶7, v/v; 15 mL). Separation of the targets was performed on a ZORBAX SB-C18 reversed-phase column (250 mm×4.6 mm, 5 μm) using an acetonitrile-methanol-water system as the mobile phase. The method was verified by spiking mixed urine samples at three levels (1, 5, and 50 μg/L), with the recoveries ranging from 84.3% to 119.8%. Except for bisphenols (BPS), whose matrix effect was calculated as -21.8%, the matrix effects of other analytes were lower than 20%, indicating low matrix interference. The linear ranges of the analytes varied from 0.1-500 μg/L to 1-500 μg/L, with correlation coefficients higher than 0.995. The method limits of quantification for target chemicals ranged from 0.03 to 0.30 μg/L, and the relative standard deviations of intra- and inter-day experiments were 1.4%-8.4% and 5.7%-14.6%, respectively, suggesting high stability and reproducibility. The method was successfully applied to the determination of ten BPs and five PBs in 10 urine samples from a general population. The concentrations of target chemicals in the human urine samples varied. Methylparaben (MeP), ethylparaben (EtP), propylparaben (PrP), and bisphenol A (BPA) were detected in all samples, with median mass concentrations of 1.10, 0.60, 0.21, and 0.55 μg/L, respectively. The detection rates of the other chemicals were less than 50%, which may be related to the production and use of specific chemicals, their bioavailability, and biological metabolism in humans.

Objective: Chromatographic retention time correction is one of the important steps to effectively improve the accuracy of identification. This article proposed a strategy for untargeted screening of biological samples based on retention time correction., Methods: A pre-treatment method for biological samples was established. The conditions of liquid chromatography and mass spectrometry were optimized. Fourteen compounds were selected as calibration agents. The retention time correction of different samples, different injection time, different brands of instruments, changing chromatographic column and changing mobile phase were investigated., Results: Calibration agents had a wide coverage, good stability and no interference with sample determination. They could be uniformly distributed in the chromatogram in both positive and negative ion modes. The chromatogram was divided into several time intervals. Calibration agents in each time period were used for retention time linear correction, and the correction effects were good., Conclusion: The retention time correction method could eliminate the retention time drift caused by experimental conditions, improve the accuracy of qualitative analysis, and help to solve the problem of high false positive result based on mass spectrum information.

Objective: To analyze the blood differential metabolites of patients with intrahepatic cholestasis (IHC) by liquid chromatography-mass spectrometry metabolomics technology so as to find potential metabolic target. Method: Serum samples were collected from thirty patients with intrahepatic cholestasis and thirty healthy individuals after metabolomics analysis. The differential metabolites were initially screened based on the multiple differences and significance. KEGG enrichment analysis was performed on the differential metabolites to determine the candidate targets. The potential clinical application value of these characteristic metabolites was analyzed using the receiver operating characteristic curve. Result: A total of thirty patients with intrahepatic cholestasis and thirty healthy adults were included. The age difference between the two groups was not statistically significant ( P >0.05). The clinical condition was consistent with the statistically significant differences in liver biochemical indicators, blood routine, coagulation, and inflammatory indicators between the two groups ( P <0.05). Furthermore, a blood metabolomics screening analysis revealed 99 differentially expressed metabolites associated with intrahepatic cholestasis. Of these, 15 showed statistically significant differences. Glucose, lipid, and energy metabolisms were the various primary types of differential metabolites involved. The receiver operating characteristic curve>0.9 included the following twelve kinds of metabolites: 1H-indole-3-carboxaldehyde, 6-hydroxy-1H-indole-3-acetamide, phenylalanyl tryptophan, 1-methylguanosine, 2-ethoxy-5-methylpyrazine, p-hydroxybenzaldehyde, 5-(2-chlorophenyl)-3,4-dihydro-2H-pyrrole, methylthioadenosine, alanylisoleucine, anabsinthin, N-acetyl-DL-histidine monohydrate, N-methylnicotinamide, and others. The fifteen metabolites that were previously identified and calculated according to the differential quantitative value of the metabolite corresponding ratio exhibited fold-changes in the upregulated and downregulated potential biomarkers (phenylalanine tryptophan, phenylalanine, 5'-methylthioadenosine, anabsinthin, and N-methylnicotinamide) in combination with the area under the receiver operating characteristic curve>0.9. Conclusion: Phenylalanyl tryptophan, phenylalanylalanine, 5'-methylthioadenosine, anabsinthin, and N-methylnicotinamide may serve as potential metabolic markers to distinguish patients with cholestasis from healthy controls. N-methylnicotinamide, among them, is of great importance as a potential marker.

Glycomics, an emerging "omics" technology that was developed after genomics and proteomics, is a discipline that studies the composition, structure, and functions of glycomes in cells, tissues, and organisms. Glycomics plays key roles in understanding the laws of major life activities, disease prevention and treatment, and drug quality control and development. At present, the structural analysis of glycans relies mainly on mass spectrometry. However, glycans have low abundance in biological samples. In addition, factors such as variable monosaccharide compositions, differences in glycosidic bond positions and modes, diverse branching structures, contribute to the complexity of the compositions and structures of glycans, posing great challenges to glycomics research. Liquid chromatography can effectively remove matrix interferences and enhance glycan separation to improve the mass spectrometric response of glycans. Thus, liquid chromatography and liquid chromatography coupled with mass spectrometry are important technical tools that have been actively applied to solve these problems; these technologies play indispensable roles in glycomics research. Different studies have highlighted similarities and differences in the applications of various types of liquid chromatography, which also reflects the versatility and flexibility of this technology. In this review, we first discuss the enrichment methods for glycans and their applications in glycomics research from the perspective of chromatographic separation mechanisms. We then compare the advantages and disadvantages of these methods. Some glycan-enrichment modes include affinity, hydrophilic interactions, size exclusion, and porous graphitized carbon adsorption. A number of newly developed materials exhibit excellent glycan-enrichment ability. We enumerate the separation mechanisms of reversed-phase high performance liquid chromatography (RP-HPLC), high performance anion-exchange chromatography (HPAEC), hydrophilic interaction chromatography (HILIC), and porous graphitic carbon (PGC) chromatography in the separation and analysis of glycans, and describe the applications of these methods in the separation of glycans, glycoconjugates, and glyco-derivatives. Among these methods, HILIC and PGC chromatography are the most widely used, whereas HPAEC and RP-HPLC are less commonly used. The HILIC and RP-HPLC modes are often used for the separation of derived glycans. The ionization efficiency and detectability of glycans are significantly improved after derivatization. However, the derivatization process is relatively cumbersome, and byproducts inevitably affect the accuracy and completeness of the detection results. HPAEC and PGC chromatography exhibit good separation effects on nonderivative glycans, but issues related to the detection integrity of low-abundance glycans owing to their poor detection effect continue to persist. Therefore, the appropriate analytical method for a specific sample or target analyte or mutual verification must be selected. Finally, we highlight the research progress in various chromatographic methods coupled with mass spectrometry for glycomics analysis. Significant progress has been made in glycomics research in recent years owing to advancements in the development of chromatographic separation techniques. However, several significant challenges remain. As the development of novel separation materials and methods continues, chromatographic techniques may be expected to play a critical role in future glycomics research.

Objective: To establish collection methods and laboratory testing methods for qualitative and quantitative analysis of 9 typical active pharmaceutical ingredient in the workplace air. Methods: In December 2021, a mixed solution of nine analytes was prepared and then dispersed in aerosol state to simulate sampling. Glass fiber filter membrane was selected as air collector and collected active pharmaceutical ingredient in the air at a rate of 2.0 L/min for 15 minutes. Then, the obtained filter membrane samples were eluted with 25%ACN/75%MeOH. Finally, the eluent was qualitatively and quantitatively analyzed with liquid chromatography-triple quadrupole mass spectrometer. Results: This method could effectively collect active pharmaceutical ingredient in the air, with an average sampling efficiency of more than 98.5%. The linear correlation coefficient r was greater than 0.9990. The lower limit of quantification for each analyte ranged from 0.6~500.0 ng/ml, and the average recovery rate ranged from 97.6%~102.5%. Conclusion: This method could simultaneously collect 9 active pharmaceutical ingredient in the workplace air, and could provide accurate qualitative and quantitative analysis in subsequent laboratory tests.

Hypoalbuminemia is one of the important clinical features of decompensated cirrhosis. As the disease progresses, not only does the total albumin concentration decrease, but so does the proportion of albumin that remains structurally and functionally intact. The structural and functional integrity of albumin is essential for its normal physiological role in the body. This led to the concept of "effective albumin concentration," which may be much lower than the total albumin concentration routinely measured clinically in patients with advanced cirrhosis. Liquid chromatography-tandem mass spectrometry, and electron paramagnetic resonance (EMR) are emerging technologies for effective albumin concentration detection, showing promising clinical application prospects, but research in patients with cirrhosis is still in the preliminary stage. Therefore, this article will comprehensively summarize the latest research on the aspects of effective albumin detection methods, liquid chromatography-tandem mass spectrometry, and electron paramagnetic resonance, as well as their applications.

Elucidating the quality markers(Q-markers) of traditional Chinese medicines is essential for understanding the mechanisms of action and promoting the rational use of traditional Chinese medicines as well as for developing traditional Chinese medicine-derived drugs. Studies have shown that surface plasmon resonance(SPR) is promising in this field. This study proposed a method based on pull-down with SPR chips to predict the Q-markers of Angong Niuhuang pills(AGNHP). Firstly, 71 main chemical components of AGNHP were analyzed by UPLC-Q-TOF-MS, and then network pharmacology was employed to predict the potential targets of AGNHP against stroke. Secondly, the STAT3 protein chip was constructed, and the extract of AGNHP was recovered by pull-down of the SPR system for STAT3 ligand. The potential active ingredients were collected, enriched, and identified as coptisine, palmatine, epiberberine, berberine, worenine, demethyleneberberine, jatrorrhizine, tetrahydrocoptisine, baicalein, and baicalin methyl ester. Next, the affinity constants of the 10 active ingredients were determined as 44.7, 44, 58.1, 51.3, 39.7, 32.1, 49.2, 69.1, 19.7, and 24.9 μmol·L~(-1), respectively. The molecular docking results showed that the 10 compounds could compete for binding with STAT3. This is the first report that SPR combined with UPLC-Q-TOF-MS is reliable and feasible for determining the active ingredients of AGNHP at the molecular level from complex systems. STAT3 could be used as a potential target for the biological quality evaluation of AGNHP.

Objective: To establish a method for the determination of two perfluorinated compounds in urine by liquid chromatography-tandem mass spectrometry. Methods: In November 2022, urine samples were extracted by acidic methanol, purified by WAX solid phase extraction column, and eluted with methanol water, then Waters ACQUITY UPLC BEH C18 column (100 mm×2.1 mm, 1.7 μm) was used with 1.0 mmol/L ammonium acetate solution and methanol as mobile phase. The gradient elution was carried out, the detection was carried out by electrospray negative ion multiple response monitoring (MRM) mode, and the quantitative method was internal standard method. Results: Perfluorooctanoic acid and perfluorooctane sulfonic acid had a good linear relationship in the concentration range of 0.5-50.0 μg/L, and the correlation coefficient was >0.999. The limit of detection was 0.017 μg/L, and the limit of quantitation was 0.005 μg/L. The average recoveries were 96.3% and 101.8%, respectively. Days of precision were 3.5%-6.2% and 3.1%-7.4%, respectively, daytime precision were 4.3%-6.8% and 4.7%-8.1%, respectively. Conclusion: The established method of liquid chromatography-tandem mass spectrometry is high sensitivity and accuracy, and is suitable for the determination of perfluorooctanoic acid and perfluorooctane sulfonic acid in human urine.

Objectives: To study the changes of protein levels in peripheral blood after it dried., Methods: The proteins from whole blood and bloodstains were detected by liquid chromatography-tandem mass spectrometry (LC-MS/MS) and normalized by the label-free quantification (LFQ) method. The differential proteins were analyzed by using R 4.2.1 software, limma and edgeR package. The analysis of biological function, signaling pathway and subcellular localization for the differential proteins was then performed., Results: A total of 623 and 596 proteins were detected in whole blood and bloodstains, respectively, of which 31 were statistically significant in the quantitative results, including 10 up-regulated and 21 down-regulated proteins in bloodstains., Conclusions: The protein abundances in whole blood and bloodstains are highly correlated, and the variation of protein abundances may be related to the changes of endogenous and structural proteins in cells. The application of proteomics technology can assist the screening and identification of protein biomarkers, thereby introducing new biomarkers for forensic research.

This study investigated the differences in excretion kinetics of three alkaloids and their four metabolites from Simiao Pills in normal and type 2 diabetic rats. The diabetes model was established in rats by injection of streptozotocin, and the alkaloids in urine, feces, and bile of normal and diabetic rats were detected by LC-MS/MS to explore the effect of diabetes on alkaloid excretion of Simiao Pills. The results showed that 72 h after intragastric administration of the extract of Simiao Pills, feces were the main excretion route of alkaloids from Simiao Pills. The total excretion rates of magnoflorine and berberine in normal rats were 4.87% and 56.54%, which decreased to 2.35% and 35.53% in diabetic rats, which had statistical significance(P&lt;0.05). The total excretion rates of phellodendrine, magnoflorine, and berberine in the urine of diabetic rats decreased significantly, which were 53.57%, 60.84%, and 52.78% of those in normal rats, respectively. After 12 h of intragastric administration, the excretion rate of berberine in the bile of diabetic rats increased significantly, which was 253.33% of that of normal rats. In the condition of diabetes, the excretion rate of berberine metabolite, thalifendine significantly decreased in urine and feces, but significantly increased in bile. The total excretion rates of jateorrhizine and palmatine in the urine increased significantly, and t&#95;(1/2) and K&#95;e changed significantly. The results showed that diabetes affected the in vivo process of alkaloids from Simiao Pills, reducing their excretion in the form of prototype drug, affecting the biotransformation of berberine, and ultimately increasing the exposure of alkaloids in vivo, which would be conducive to the hypoglycemic effect of alkaloids. This study provides references for the clinical application and drug development of Simiao Pills in diabetes.

From the perspective of technical evaluation, this study reviewed the current situation of application and clinical application of medical device products were detected by liquid chromatography-tandem mass spectrometry in the market in recent years. The regulatory requirements of these products in China, USA, EU and Japan were compared and analyzed, and the monitoring situation of adverse events after listing, the standards for reference and the domestic and foreign regulatory documents were combined, the clinical application and regulatory risks of the product were analyzed. The problems such as pre-treatment, system matching, adequacy of performance index requirements, inter-room consistency, reference interval and registration unit were discussed and suggestions for supervision were given, with a view to the field of product R&D and production, review and approval of supervision to provide technical reference.

Traditional Chinese medicine(TCM) compound preparations have complex compositions. As a widely used TCM injection, Shuganning Injection, its in vivo processes are not yet fully understood. Determining the plasma protein binding rate is of great significance for pharmacokinetic and pharmacodynamic studies. In this experiment, the equilibrium dialysis method combined with UPLC-MS/MS technology was used to determine the plasma protein binding rates of 10 components, including p-hydroxyacetophenone, caffeic acid, baicalein, oroxylin A, geniposide, baicalin, cynaroside, oroxylin A-7-O-β-D-glucuronide, scutellarin, and hyperoside, in Shuganning Injection in rat and human plasma to provide a theoretical basis for further elucidating the in vivo processes of Shuganning Injection and guiding clinical medication. The results showed that, except for baicalein and geniposide, the plasma protein binding rates of the other eight components were higher in human plasma than in rat plasma, and there were interspecies differences. In human plasma, except for geniposide, caffeic acid, and baicalin, the plasma protein binding rates of the remaining seven components were above 80%, with baicalein and oroxylin A exceeding 90%. All components exhibit a high level of binding to plasma proteins, with the exception of geniposide.

Objectives: To establish a simple and rapid qualitative and quantitative detection method of dexmedetomidine in blood., Methods: Blood was separated on the Allure PFP Propyl liquid chromatography column with isocratic elution after it was precipitated by acetonitrile and filtered. Qualitative and quantitative analysis of dexmedetomidine was performed using positive ion scan mode and multi-reaction monitoring mode., Results: The limit of detection of dexmedetomidine in blood was 0.2 ng/mL and the limit of quantification was 0.5 ng/mL. The linearity of the method was good in the range of 0.5-1 000 ng/mL, and the correlation coefficient was greater than 0.99. The accuracy of the method was 90.34%-112.67% and the extraction recovery was 50.05%-91.08%, with no significant matrix effect., Conclusions: This method is simple, selective and suitable for the qualitative and quantitative analysis of dexmedetomidine in blood, which can provide a reference for drug-facilitated cases involving dexmedetomidine.

Objective: To establish a method for the rapid determination of acetaminophen (APAP) in human plasma by LC-MS/MS. Methods: The plasma samples were extracted by methanol and acetonitrile (1: 1) and purified directly. C(18) column was used for sample separation. The mobile phase were methanol (5 mmol/L ammonium acetate) and water (5 mmol/L ammonium acetate). Samples were analyzed by LC MS/MS with the electrospray ionization multi reaction monitoring (MRM) mode. Results: The calibration curves of APAP was linear in the concentration range of 0~10 mg/L, the correlation coefficient ( r ) was greater than 0.999 0. The relative standard deviation within and between batches was less than 10%. The recovery rate were 96.81%~101.7%. The detection limit of the method was 0.1 μg/L and the lower limit of quantification was 0.3 μg/L. Conclusion: This method has strong specificity, high sensitivity and reliable determination results. It is suitable for the rapid analysis of clinical plasma samples.

Objective: Using liquid chromatography-ion trap-time of flight-mass spectrometry to establish a soybean phospholipids(PL) analysis method, carry out comprehensive structural identification and quantitative analysis of soybean PL molecule species, and obtain soybean PL molecular composition and content data., Methods: The PL profiles of 10 soybean varieties cultivated in northeast China were determined by a hydrophilic interaction liquid chromatography-ion trap-time of flight-mass spectrometry(HILIC-ESI-IT-TOF-MS) system. The hydrophilic interaction liquid chromatography realized class separation of PLs, and ion trap-time of flight-mass spectrometry realized the estimation of head group type, fatty acyl structure, and substituent position. The identified PL molecule species were quantified using accurate mass extraction and internal standard method., Results: A total of 101 PL molecular species from 11 classes were estimated in soybean seeds, including 20 phosphatidylcholines(PC), 15 phosphatidylethanolamines(PE), 17 phosphatidylinositols(PI), 12 phosphatidylglycerols(PG), 9 phosphatidic acids(PA), 6 phosphatidylserines(PS), 5 lysophosphatidylcholines(LPC), 5 lysophosphatidylethanolamines(LPE), 6 lysophosphatidylinositols(LPI), 4 lysophosphatidylglycerols(LPG) and 2 lysophosphatidicacids(LPA). The limits of detection for the target object were ≤ 60 ng/mL and R~2 were all &gt;0.99. The total concentration of PL ranged from 6873.1 to 12 678.6 μg/g in detected soybeans. Generally, most of the detected soybean cultivars were great resources of PL, especially SN-29, SN-61, HN-40 and DN-690. The concentrations of PC and PE in the tested soybean were higher, followed by PI, PG, PA and PS. Among the lysophospholipids, the concentration of LPC was the highest, followed by LPE, LPI, LPG and LPA., Conclusion: The soybean PL component analysis method established based on the HILIC-IT-TOF-MS system can achieve good separation of various types of PL, and can accurately characterize the head group type, fatty acyl structure and substituent position of PL molecule species. The molecular composition and content data of soybean PL were obtained.

Objectives: To establish an LC-MS/MS method based on single hair micro-segmental technique, and verify the detection of 42 psychoactive substances in 0.4 mm hair segments., Methods: Each piece of single hair was cut into 0.4 mm segments and extracted by sonication and the segments were immersed in dithiothreitol-containing extraction medium. Mobile phase A was the aqueous solution containing 20 mmol/L ammonium acetate, 0.1% formic acid, and 5% acetonitrile. Mobile phase B was acetonitrile. An electrospray ionization source in positive ion mode was used for data acquisition in multiple reaction monitoring (MRM) mode., Results: The 42 psychoactive substances in hair had a good linear relationship within their respective linear ranges ( r >0.99), the limits of detection were 0.2-10 pg/mm, the limits of quantification were 0.5-20 pg/mm, the intra-day and inter-day precisions were 1.5%-12.7%, the intra-day and inter-day accuracies were 86.5%-109.2%, the recovery rates were 68.1%-98.2%, and the matrix effects were 71.3%-111.7%. The method was applied to hair samples collected from one volunteer at 28 d after a single dose of zolpidem, with zolpidem detected in 5 hairs was 1.08-1.60 cm near the root tip, and the concentration range was 0.62-20.5 pg/mm., Conclusions: The micro-segmental technique of single hair analysis can be applied to the investigation of drug-facilitated sexual assault cases.

By investigating the contamination status and predicting the exposure risk of mycotoxin in Coicis Semen, we aim to provide guidance for the safety supervision of Chinese medicinal materials and the formulation(revision) of mycotoxin limit standards. The content of 14 mycotoxins in the 100 Coicis Semen samples collected from five major markets of Chinese medicinal materials in China was determined by UPLC-MS/MS. The probability evaluation model based on Monte Carlo simulation method was established after Chi-square test and One-way ANOVA of the sample contamination data. Health risk assessment was performed on the basis of margin of exposure(MOE) and margin of safety(MOS). The results showed that zearalenone(ZEN), aflatoxin B&#95;1(AFB&#95;1), deoxynivalenol(DON), sterigmatocystin(ST), and aflatoxin B&#95;2(AFB&#95;2) in the Coicis Semen samples had the detection rates of 84%, 75%, 36%, 19%, and 18%, and the mean contamination levels of 117.42, 4.78, 61.16, 6.61, and 2.13 μg·kg~(-1), respectively. According to the limit standards in the Chinese Pharmacopoeia(2020 edition), AFB&#95;1, AFs and ZEN exceeded the standards to certain extents, with the over-standard rates of 12.0%, 9.0%, and 6.0%, respectively. The exposure risks of Coicis Semen to AFB&#95;1, AFB2, ST, DON, and ZEN were low, while 86% of the samples were contaminated with two or more toxins, which needs more attention. It is suggested that the research on the combined toxicity of different mycotoxins should be strengthened to accelerate the cumulative exposure assessment of mixed contaminations and the formulation(revision) of toxin limit standards.

Objectives: To establish a method for the detection of carbamazepine and its metabolites 10,11-dihydro-10,11-epoxycarbamazepine and 10,11-dihydro-10-hydroxycarbamazepine in blood samples by liquid chromatography-tandem mass spectrometry (LC-MS/MS)., Methods: The blood samples were treated with 1-butyl-3-methylimidazolium hexafluorophosphate as an extraction solvent. The samples were extracted by ultrasound-assisted extraction and separated by ZORBAX Eclipse Plus C18, 95Å column. The mobile phase A aqueous solution containing 0.1% formic acid and 10 mmol/L ammonium acetate, and mobile phase B mixed organic solvent containing acetonitrile/methanol ( V acetonitrile ∶ V methanol =2∶3) were used for gradient elution at the flow rate of 1.00 mL/min. An electrospray ion source in positive mode was used for detection in the multiple reaction monitoring., Results: The linearities of carbamazepine and its metabolites 10,11-dihydro-10,11-epoxycarbamazepine and 10,11-dihydro-10-hydroxycarbamazepine in blood samples were good within the corresponding range, with correlation coefficients ( r ) greater than 0.995 6. The limits of detection were 3.00, 0.40 and 1.30 ng/mL, respectively. The limit of quantitation were 8.00, 1.00 and 5.00 ng/mL, respectively. The extraction recoveries ranged from 76.00% to 106.44%. The relative standard deviations of the intra-day and inter-day precisions were less than 16%. Carbamazepine and its main metabolite 10,11-dihydro-10,11-epoxycarbamazepine were detected in blood samples of death cases with a mass concentration of 2.71 μg/mL and 252.14 ng/mL, respectively., Conclusions: This method has high sensitivity and good selectivity, which is suitable for the detection of carbamazepine and its metabolites in blood samples, and can be used for carbamazepine-related forensic identifications.

Mass spectrometry technology is becoming an important tool for clinical analysis due to its high specificity, high sensitivity and high multi-component detection capability. The current applications of this technology are mainly in liquid chromatography-tandem mass spectrometry (LC-MS/MS), matrix-assisted laser desorptionionization time-of-flight mass spectrometry (MALDI-TOF-MS), inductively coupled plasma mass spectrometry (ICP-MS), gas chromatography-mass spectrometry (GC-MS) and the related in vitro diagnostic kits. At present, the number of medical device (MD) based on mass spectrometry technology is growing rapidly, especially the number of LC-MS/MS and MALDI-TOF-MS registered MD products, and the standardization of relevant product quality requirements is also being effectively carried out. In general, clinical mass spectrometry equipment is still mainly imported, and the equipment price is relatively high. The development of mass spectrometry kits is mainly based on imported platforms, and domestic equipment is still in its infancy; the further promotion of clinical application of mass spectrometry also depends on the progress of the automation and standardization of the analysis procedure. To investigate the detection performance of mass spectrometry systems, it is necessary to fully consider the characteristics of mass spectrometry technology itself.

An analytical method for 10 mycotoxins in Hippophae Fructus medicinal and edible products was established in this study, and the contamination of their mycotoxins was analyzed. First of all, the mixed reference solution of ten mycotoxins such as aflatoxin, ochratoxin, zearalenone, and dexoynivalenol was selected as the control, and the Hippophae Fructus medicinal and edible products were prepared. Secondly, based on the ultra-performance liquid chromatography-tandem mass spectrometry(UPLC-MS/MS) technology, 10 mycotoxins in Hippophae Fructus medicinal and edible products were quantitatively investigated and their content was determined. Finally, the contamination of mycotoxins was analyzed and evaluated. The optimal analysis conditions were determined, and the methodological inspection results showed that the 10 mycotoxins established a good linear relationship(r&gt;0.99). The method had good repeatability, test sample specificity, stability, and instrument precision. The average recovery rates of 10 mycotoxins in Hippophae Fructus medicinal products, edible solids, and edible liquids were 90.31%-109.4%, 87.86%-107.8%, and 85.61%-109.1%, respectively. Relative standard deviation(RSD) values were 0.22%-10%, 0.75%-13%, and 0.84%-8.5%, repsectively. Based on UPLC-MS/MS technology, the simultaneous determination method for the limits of 10 mycotoxins established in this study has fast detection speed, less matrix interference, high sensitivity, and accurate results, which is suitable for the limit examination of 10 mycoto-xins in Hippophae Fructus medicinal and edible products.

Objective: To establish a rapid and accurate method for the determination of 25-hydroxyvitamin D&#95;3(25(OH)D&#95;3) and 25-hydroxyvitamin D&#95;2(25(OH)D&#95;2)in serum by pre-column derivatization with stable isotope labeling and ultra performance liquid chromatography-quadrupole electrostatic field orbitrap high-resolution mass spectrometry, which could be used to diagnose vitamin deficiency and to assess the nutritional status of vitamin D in the population., Methods: The serum samples with isotopic internal standard were extracted by mixed extraction solvent(ethyl acetate∶hexane = 2∶1, V/V), centrifuged and dried by the nitrogen blowing, and derivatized with 4-phenyl-1, 2, 4-triazoline-3, 5-dione(PTAD). The reaction products were separated on a BEH C&#95;(18) column(2.1 mm×50 mm, 1.7 μm), and eluted with a 0.1% formic acid/water solution-acetonitrile gradient. The mass spectrometry was performed in positive electrospray ionization(ESI~+) and parallel reaction monitoring(PRM) for the detection of the targets, and quantified by isotope internal standard., Results: The limits of detection both for 25(OH)D&#95;3 and 25(OH)D&#95;2 were 0.01 ng/mL and the limits of quantification were 0.03 ng/mL. The concentration series of 25(OH)D&#95;2 ranged from 0.5 to 40.0 ng/mL and the concentration series of 25(OH)D&#95;3 ranged from 2.5 to 200.0 ng/mL. The recoveries(n=5) were 95.7%-101.3% for 25(OH)D&#95;3, and 98.7%-108.6% for 25(OH)D&#95;2, with the relative standard deviations(RSDs) of 0.5%-4.9% and 2.2%-3.4%, respectively. The accuracy of the determination of 25(OH)D&#95;3 and 25(OH)D&#95;2 in Level 2 serum of the 25(OH)D standard reference material NIST SRM 972a was 104.8% and 94.9%, respectively. The M(P25, P75)serum levels of 25(OH)D&#95;3 and 25(OH)D&#95;2 for 116 pregnant women at the first trimester from Beijing were 25.7(20.8, 32.6) ng/mL and 0.8(0.4, 1.1) ng/mL, respectively., Conclusion: This method is highly sensitive, qualitatively accurate and suitable for evaluation and monitoring the nutritional status of vitamin D in the population.

Liquid chromatography tandem mass spectrometry (LC-MS/MS) is an analytical method that combines high separation of liquid chromatography with high selectivity and sensitivity of mass spectrometry. In recent years, LC-MS/MS has been widely used in clinical practice, including screening of inherited disorders, determination of endogenous compounds and analysis of biomarkers. LC-MS/MS is of great value to the precision prevention, diagnosis and treatment of some diseases due to its accurate data. This article not only illustrates the advantages of LC-MS/MS in precision medicine, but also prospects the future trend of LC-MS/MS in clinical practice, which expects to promote the development of clinical LC-MS/MS in the prevention, diagnosis and treatment of diseases.

The purpose of this study was to understand the effect of gender on the traits of wool. One-year-old male and female Chinese merino sheep (JunKen type) were used to screen differentially expressed proteins in skin tissues by quantitative proteomics using liquid chromatography-tandem mass spectrometry (LC-MS/MS) and data independent acquisition (DIA) strategy. This was followed by GO function annotation, KEGG metabolic pathway and protein network interaction analysis on the differential proteins obtained. The result showed that there were 674 differentially expressed proteins between male and female groups, whereas 280 proteins were up-regulated and 394 proteins were down-regulated in the male group. Through further comparison and analysis, there were 43 differentially expressed proteins related to skin hair follicle development and wool phenotype, 30 up-regulated and 13 down-regulated. The GO annotation analysis of differentially expressed proteins were mainly enriched in 37 processes of molecular function such as oxygen binding, chondroitin sulfate binding, heme binding, glutathione peroxidase activity and glutathione transferase activity; 120 biological processes such as cellular oxidant detoxification, regulation of muscle contraction, notch signaling pathway, calcium ion transmembrane transport and glutathione metabolism; and 31 processes related to cellular components such as mast cell granule, nucleus, sarcoplasmic reticulum and endoplasmic reticulum lumen. KEGG analysis showed that the differentially expressed proteins were involved sixteen signaling pathways, among which MAPK and p53 signaling pathways were closely related to wool growth and development. The protein network interaction analysis discovered that COL1A1 was closely related to MMP2, SPARC, THBS1 and other differentially expressed proteins, which might play a key role in wool growth and development. Thus, this study obtained basic data for revealing the molecular mechanism of sheep wool traits of different gender.

Metabolomics, which mainly studies the metabolite components of organisms, tissues, cells and their dynamic changes, is an emerging omics technology following genomics and proteomics. Metabolites are the final products of cellular regulation, and the concentration of metabolites is considered to be the ultimate response of a biological system to genetic or environmental changes. Secondary metabolites with chemical diversity are widely present in living organisms, thus accurate quantification of secondary metabolites through appropriate analytical platforms is an important task of metabolomics. Liquid chromatography-tandem mass spectrometry (LC-MS/MS) is the most commonly used method for the detection of metabolites, providing a basis for the wide application of plant secondary metabolites. This review summarizes the advances of using LC-MS/MS techniques for the detection of phytohormone, folic acid, flavonoids and other secondary metabolites.

Methotrexate (MTX) is a widely used immunosuppressive drug. Large-dose of MTX is used for the treatment of cancer while low-dose is used for the treatment of rheumatoid arthritis (RA). This study aimed to explore the effect of MTX on the urinary proteome of rats. MTX was given to rats orally to construct an MTX intragastric administration rat model. The urine of the rats were collected within 10 hours after giving MTX, and the urine proteins of the rats were analyzed by liquid chromatography tandem mass spectrometry (LC-MS/MS). A total of 31 differential proteins were identified, of which 7 proteins were related to the effect MTX and the symptom of RA. The biological processes of some rats reflected the effect of MTX on the body's glutathione metabolism and the JAK/STAT signaling pathway, which indicated that urine proteins have the ability to reflect the effects of MTX on the body of rats. The spectrum of the differential proteins of each single rat showed that different individuals respond to the drug quite differently.

The purpose of this study was to explore the effect of acute hypoxia on urine proteome in rats. In this study, rats were placed in a hypoxic chamber simulating a plateau environment at an altitude of 5 000 m for 24 hours. Urine samples were collected at 0, 12, and 24 h after hypoxia. Urinary proteins were profiled using liquid chromatography coupled with tandem mass spectrometry (LC-MS/MS). Compared with the control (before hypoxia), a total of 144 differentially expressed proteins were identified in the hypoxia 12 h group, and 129 differentially expressed proteins were identified in the hypoxia 24 h group. Functional annotation analysis revealed that these differentially expressed proteins were involved in a series of biological pathways related to hypoxic stress, such as anti-oxidative stress, glycolysis, complement and coagulation cascade. Our results suggest that the urinary proteome can reflect significant changes upon acute hypoxic stimulation. These findings may provide an approach to judge the hypoxia state of the body and help to assist the detection of hypoxia state.

Due to its ultra-high sensitivity, specificity and throughput, liquid chromatography tandem mass spectrometry (LC-MS/MS) has become an important analytical tool in clinical laboratories in quantifying various small molecules, such as vitamins, bile acids, steroids and other internal metabolites relevant to maternal diseases. As an effective means of screening and diagnosing diseases in preventive medicine, LC-MS/MS has been widely used in maternal and child health, contributing to the reduction of the incidence of maternal and child diseases and premature morbidity and mortality. At present, LC-MS/MS is an emerging and powerful platform in laboratory testing in China, facing both challenges and opportunities. In this article, the representative applications in the field of maternal and child health are summarized and discussed, along with the major hurdles of LC-MS/MS in clinical recognition and implementation.

A high-performance liquid chromatography-tandem mass spectrometry(LC-MS/MS) was developed for simultaneously determining the components(magnoflorine, jatrorrhizine, berberrubine, coptisine, berberine) of Jiaotai Pills and Fluoxetine in plasma of rats with chronic unpredictable mild stress(CUMS)-induced depression to investigate the pharmacokinetic herb-drug interaction of Jiaotai Pills and Fluoxetine in the rats. The six components showed good linear relationship within the corresponding concentration ranges, and the method showed high specificity, accuracy, precision, and stability. Their pharmacokinetic parameters were calculated by DAS 3.2.2, and the results showed that the in vivo metabolic processes of the six components accorded with the characteristics of non-compartmental model. When Jiaotai Pills and Fluoxetine were used together, the AUC&#95;(0-t), AUC&#95;(0-∞), C&#95;(max), and C&#95;(av) of magnoflorine all significantly increased(P&lt;0.05), while the pharmacokinetic trend of berberrubine was opposite to that of magnoflorine, as manifested by the decrease in AUC&#95;(0-t), AUC&#95;(0-∞), T&#95;(max), C&#95;(max), and C&#95;(av)(P&lt;0.01, P&lt;0.05). The pharmacokinetic characteristics of jatrorrhizine, coptisine, and berberine followed the trend of berberrubine. There was no significant difference in the pharmacokinetic characteristics of Fluoxetine in the single or combination groups. This study suggests that the enhanced antidepressant efficacy of Jiaotai Pills and Fluo-xetine may be attributed to the pharmacokinetic interaction.

Objectives: To analyze the characteristics of diphenidol poisoning cases and to provide clues and technical means for the identification of such cases., Methods: Biological samples of 9 deaths caused by diphenidol poisoning were detected by ultra-high performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS), and the characteristics of these cases were analyzed retrospectively., Results: Most of the deaths caused by diphenidol poisoning were young females. The dosage was between 60 and 300 tablets, and the mass concentration of diphenidol in the postmortem blood ranged from 0.87 to 99.00 μg/mL. There was no correlation between the dosage and the concentration of diphenidol in the blood., Conclusions: Diphenidol poisoning has the characteristics of high concealment and lethality. More attention should be paid to suicide cases, and diphenidol should be recommended as a routine detection item to avoid missing detection.

To identify the pharmacodynamic material basis of root bark of Caesalpinia decapetala extract and clarify the dynamic changes and distribution characteristics of the compounds in vivo.UPLC-MS/MS was used for simultaneous determination of 3-deoxysappanchalcone, isoliquiritigenin, protosappanin B, and protosappanin B-10-O-β-D-glucoside in plasma, heart, liver, spleen, lung, kidney, stomach and duodenum of rats, to further study the pharmacokinetics and tissue distribution of root bark of C.decapetala extract in rats.Statistical analysis of obtained data demonstrated that the established analytical methods of the four components in biological matrix met the requirements of biological sample determination.The pharmacokinetic parameters showed that the t&#95;(1/2 z), T&#95;(max), C&#95;(max), AUC&#95;(0-t), MRT&#95;(0-t), and CL&#95;(z/F) of each component were 4.57-13.47 h, 0.22-0.51 h, 27.60-6 418.38 μg·L~(-1), 112.45-11 824.25 h·μg·L~(-1), 3.89-9.01 h, and 9.85-96.87 L·h~(-1)·kg~(-1), respectively.The results of tissue distribution revealed that at different time points, the components were widely but unevenly distributed in the body.Specifically, they were more distributed in the stomach and duodenum, followed by liver, spleen, lung, and kidney, and the least distribution was observed in the heart.

This study aims to establish a rapid and sensitive UPLC-MS/MS method for simultaneously determining the content of strychnine and paeoniflorin in plasma and brain tissue of rats, and compare the pharmacokinetic behavior and brain tissue distribution of paeoniflorin combined with normal and toxic doses of strychnine in rats after percutaneous administration. Compared with those in the toxic-dose strychnine group, the AUC&#95;(0-t), AUC&#95;(0-∞), and C&#95;(max) of strychnine decreased by 51.51%, 45.68%, and 46.03%, respectively(P&lt;0.01), and the corresponding values of paeoniflorin increased by 91.41%, 102.31%, and 169.32%, respectively(P&lt;0.01), in the compatibility group. Compared with the normal-dose strychnine group, the compatibility group showed insignificantly decreased C&#95;(max), AUC&#95;(0-t), and AUC&#95;(0-∞) of strychnine, increased C&#95;(max) and T&#95;(max) of paeoniflorin(P&lt;0.01), 66.88% increase in AUC&#95;(0-t), and 70.55% increase in AUC&#95;(0-∞) of paeoniflorin. In addition, the brain tissue concentration of strychnine decreased and that of paeoniflorin increased after compatibility. The combination of paeoniflorin with normal dose and toxic dose of strychnine can inhibit the percutaneous absorption of strychnine, and greatly promote the percutaneous penetration of paeoniflorin, whereas the interaction mechanism remains to be explored. The UPLC-MS/MS method established in this study is easy to operate and has good precision. It is suitable for in vivo study of pharmacokinetic behavior and brain tissue distribution of paeoniflorin and strychnine after percutaneous administration in rats, which provides reference for the safe and rational clinical use of strychnine and the combined use of drugs, and lays a solid foundation for the development of external preparations containing Strychni Semen.

Objective: To establish a method for simultaneous detection of melamine(MEL), ammeline(AMN), ammelide(AMD) and cyanuric acid(CYA) in urine by ultra-performance liquid chromatography-tandem mass spectrometry(UPLC-MS/MS)., Methods: After the urine sample was added to the internal standard, they were mixed by acetonitrile, ultrasonic extraction and centrifugation, enriched by MCX or MAX solid phase extraction column, eluted with 5% ammoniated methanol or 2% formic acid methanol, dried under nitrogen at 40 ℃, separated by Amide chromatography column(2.1 mm×100 mm, 1.7 μm), qualitatively and quantitatively analyzed by mass spectrometer in the simultaneous scanning mode of positive and negative ions., Results: Melamine and its derivatives were completely separated with great chromatography peak. The limit of detection(LOD) for melamine, ammeline, ammelide and cyanuric acid were 0.03, 0.04, 0.04 and 0.05 ng/mL, and the limit of quantification(LOQ) were 0.11, 0.12, 0.14 and 0.15 ng/mL, respectively. The recovery rate of standard addition samples of 0.2, 5, 50 and 200 ng/mL ranged from 94.6% to 106.5%, the intra-day precision was between 0.73% and 8.34%, and the inter-day precision was less than 6.80%(n=6). At low concentrations, AMD and CYA mainly showed matrix enhancing effect, while AMN showed matrix inhibitory effect with increasing concentration. The overall detection rate of melamine and its derivatives was 75.0% in 60 parcels of random urine. The average concentration of urinary melamine and its derivatives were higher in men., Conclusion: UPLC-MS/MS can simultaneously determine four melamine and its derivatives in urine. The LOD and LOQ of the current method were low with great accuracy and precision.

Objective: To identify differentially expressed proteins between the patients with proliferative diabetic retinopathy (PDR) and vitreous floaters, and explore treatment target for PDR based on isobaric tags for relative and absolute quantification (iTRAQ) LC-MS/MS Proteomics. Method: Vitreous samples were collected from 28 eyes of patients with PDR and 4 eyes with vitreous floaters, which served as controls. For quantitative proteomics, vitreous samples were combined and proteins extracted and labeled with iTRAQ peptide-tagging reagents. Samples were fractionated by liquid chromatography (LC), analyzed by tandem mass spectrometry (MS/MS) and Gene Ontology (GO) analyses performed on differentially expressed proteins identified in the PDR samples. Results: In the PDR vitreous, 26 proteins were identified that were differentially expressed when compared to the controls. Of these, 7 showed a significant increase ( P< 0.05) and 19 a significant decrease ( P< 0.05)in expression in PDR patients. These included some high abundance proteins including Retinoic acid receptor reactive protein 2 (PDR 1=85.0, PDR 2=83.0, Control 1=119.6, Control 2=120.2, FC=0.710, P= 0.001), Semaphorin-4B(PDR 1=64.4, PDR 2=68.8, Control 1=135.4, Control 2=146.0, FC=0.473, P= 0.023), Apolipoprotein B (PDR 1=104.4, PDR 2=106.6, Control 1=89.0, Control 2=85.3, FC=1.211, P= 0.024), and Heat shock protein 70 (PDR 1=69.3, PDR 2=75.0, Control 1=137.7, Control 2=138.3, FC=0.523, P= 0.026), which are closely related to the pathological mechanism of PDR. GO analysis clustered the differentially expressed genes into three major functional domains: Biological Processes, Molecular Function and Cellular Component. Differential gene expression was found in the categories of cellular metabolism, organonitrogen compound and carbohydrate derivative metabolic processes, transferase activity and transmembrane signaling receptor activity. KEGG Pathway analysis indicate that Chemerin signaling through Akt, Sema4B signaling via PI3K, and HIF-1α signal pathways were all altered in the PDR samples. Conclusions: In this study we identified variations in expression of genes extensively involved in key biological processes in the retina including neovascularization, cellular metabolism and transmembrane signaling, which provide new insights into the pathophysiology of PDR. Extracellular matrix was degraded and endothelial cell migration was induced by Chemerin, in addition, the destruction of blood-retinal barrier and neuronal apoptosis were induced by ApoB. Chemerin and ApoB accelerated the development of PDR. Sema 4B participated in vascular protection, HSP70 conducted anti-apoptosis. These two cytokines protected the retinal neurovascular in PDR patients. Therefore, Chemerin, Sema 4B, ApoB and HSP70 may be the treatment target for PDR. (Chin J Ophthalmol, 2019, 55:769-776) .

Objective: To establish a liquid chromatography tandem mass spectrometry method to determine the cortisol in saliva. Methods: Take 0.5 ml saliva sample into a 2 ml centrifuge tube, add excess sodium chloride and 1ml acetonitrile to it, then vortex for 3 min, centrifuge for 10 min at 15 000 r/min, and take 800 μl of the upper layer to another centrifuge tube. Finally, the sample was concentrated by a vacuum concentrator and brought to 200 μl with the initial mobile phase. Then, the sample was analyzed by liquid chromatography tandem mass spectrometry. The target compound was quantified by external standard curve method. Results: The linear range of the method was 0.02 - 5.00 ng/ml, r =0.999 9, the method limit of the detection was 0.002 ng/ml, the method limit of quantitative was 0.02 ng/ml, and the spiked recoveries were 89.60% - 98.60%. The intra - assay precision was 1.90% - 3.30%, and the inter - assay precision was 4.20% - 9.00%; samples could be stored at -20 °C for at least 14 days. The determination of cortisol could not be interfered by other endogenous substances in the sample. Conclusion: The method is simple in pretreatment, high sensitivity, good reproducibility and good recovery, and it is suitable for the quantitative analysis of cortisol in saliva for normal and occupationally stressed populations.

Objective: To establish a elution solution-liquid chromatography method for determination of p-Phenylene diamine (PPD) in workplace air. Methods: p-Phenylene diamine (PPD) in the air of workplace was collected with glass fiber filters coated with dilute sulfuric acid and extracted with an aqueous EDTA solution. The target toxicant was separated with the C(18) column and analyzed with UV detector, identified by retention time, and quantified by peak area. Results: The linear range of PPD in the air of workplace was 2.00~10.00 μg/ml, with a correlation coefficient of 0.999 96. The limit of detection was 0.07 μg/ml. The lower limit of quantification was 0.23 μg/ml. The minimum detectable concentration was 0.003 1 mg/m(3) under 45.0 L sampling volume and 2.0 ml extraction solution volume. The within-run precision of different PPD concentrations was 0.15%~2.3% and the between-run precisions was 1.4%~2.6%; The extraction efficiencies was 91.4%~95.4%; The average collection efficiencies was 96.6%; The samples could be stored for 7 days isolation of air. The potential coexistence of m-Phenylene diamine and o-Phenylene diamine with p-Phenylene diamine (PPD) in the air did not interfere with the results of determination. Conclusion: This method has high sensitivity, precision, accuracy and lower limit of detection and it is applicable for determination of p-Phenylene diamine (PPD) in workplace air.

Objective: Applying the proteomics technology to identify proteins differentially in serums of idiopathic pulmonary fibrosis patients and normal population. Methods: The study included serum samples from idiopathic pulmonary fibrosis group and normal controlled group with 30 cases of each, from the Second Hospital of Shandong University, between October 2014 and October 2015. Proteins differentially expressed in serums were quantified by the isobaric tags for relative and absolute quantization coupled with two-dimensional liquid chromatography/tandem mass spectrometry technology. The proteins were analyzed in terms of molecular function, cell location and biological processes for showing the key protein molecules which were related to the development of idiopathic pulmonary fibrosis. Results: A total of 490 kinds of proteins (with confidence coefficient above 95%) were identified by mass spectrometry and 25 kinds of differentially expressed proteins were found. Compared with the control group, we found 4 types of up-regulated proteins and 21 down-regulated ones in the serum of idiopathic pulmonary fibrosis patients. Data from the Gene ontology analysis showed that most differentially expressed proteins were in the extracellular region (92%) while pathway enrichment analysis showed that most proteins were involved in the complement and coagulation cascade pathway. Conclusion: Proteins related to the complement system coagulation cascade pathway, and the proteins function need to be further studied.

Objectives: To establish a rapid determination method with LC-MS/MS for cocaine and its metabolite benzoylecgonine in hair., Methods: Deuterated internal standards （cocaine-D₃ and benzoylecgonine-D₈） were added to the decontaminated hair. After the extraction by ultrasonication with methanol, the compounds were separated by the Restek Allure PFP propyl column, and cocaine and benzoylecgonine were simultaneously analysed in multiple reaction monitoring mode., Results: The cocaine and benzoylecgonine in hair showed a good linearity in the range of mass fraction between 0.02 and 10.00 ng/mg with the limits of detection of 0.01 ng/mg., Conclusions: The developed method is simple and rapid with a good selectivity, which is suitable for the determination of cocaine and its metabolite benzoylecgonine in hair., Competing Interests: The authors of this article and the planning committee members and staff have no relevant financial relationships with commercial interests to disclose., (Copyright© by the Editorial Department of Journal of Forensic Medicine.)

Objectives: To identify the new designer drugs which are totally unknown and not in the routine testing list by the technologies such as high-resolution mass spectrometry in drug facilitated sexual assault, in order to solve the problem in actual cases., Methods: The milky fluid from an actual case was extracted and analyzed using LC-QE, ¹H-NMR and GC-MS, respectively. The accurate masses and cluster ions isotope patterns of unknown compound were obtained by LC-QE. The molecular formula was confirmed as C₁₆H₁₂C₂N₂O based on the protons number of ¹H-NMR. The isomers diclazepam and 4-chlorodiazepam were separated and detected with GC-MS., Results: The new designer benzodiazepine as diclazepam in the milky fluid was identified. The results provided direct evidence for the investigation and qualitative analysis of such cases., Conclusions: The combined application of various methods, including LC-QE, ¹H-NMR and GC-MS, can be used to detect unknown new psychoactive substances., Competing Interests: The authors of this article and the planning committee members and staff have no relevant financial relationships with commercial interests to disclose., (Copyright© by the Editorial Department of Journal of Forensic Medicine.)

Objective: A method was developed for the determination of pentachlorophenol( PCP) in food by ultrafast liquid chromatography-tandem mass spectrometry after solid phase extraction., Methods: The sample was extracted in 8%triethylamine/acetonitrile( 70/30, V/V) and purified on a MAX-SPE cartridge. The UFLC separation was performed on a Shim-pack XR-ODS Ⅲ column( 150 mm × 2. 0 mm, 2. 2μm) with a linear gradient elution program of acetonitrile and 5 mmol/L ammonium acetate( 0. 1% formic acid) as the mobile phase. Electrospray ionization was applied and operated in the negative ion mode., Results: The limit of quantitation( LOQ) and limit of detection( LOD) for PCP were 0. 4-0. 5 μg/kg and 0. 12-0. 15 μg/kg. The calibration curve showed good linearity between 0. 5-50. 0 μg/L, and the correlative coefficients( r) were more than 0. 999. The recovery was between 82. 0%-108. 0%, and the RSD was between 1. 89%-5. 09%( n = 6)., Conclusion: The method is sensitive, reproducible, and adapts to determination of PCP in variety of foods.

Objectives: To study the content variation of selegiline and its metabolites in urine, and based on actual cases, to explore the feasibility for the identification of methamphetamine abuse and selegiline use by chiral analysis., Methods: The urine samples were tested by chiral separation and LC-MS/MS method using CHIROBIOTIC™ V2 chiral liquid chromatography column. The chiral analysis of methamphetamine and amphetamine were performed on the urine samples from volunteers of selegiline use and drug addicts whom suspected taking selegiline., Results: After 5 mg oral administration, the positive test time of selegiline in urine was less than 7 h. The mass concentrations of R（-）-methamphetamine and R（-）-amphetamine in urine peaked at 7 h which were 0.86 μg/mL and 0.18 μg/mL and couldn't be detected after 80 h and 168 h, respectively. The sources of methamphetamine and amphetamine in the urine from the drug addicts whom suspected taking selegiline were analysed successfully by present method., Conclusions: The chiral analysis of methamphetamine and amphetamine, and the determination of selegiline's metabolites can be used to distinguish methamphetamine abuse from selegiline use., Competing Interests: The authors of this article and the planning committee members and staff have no relevant financial relationships with commercial interests to disclose., (Copyright© by the Editorial Department of Journal of Forensic Medicine)

Objective: To establish a rapid and sensitive method for the analysis of eight bisphenols in breast milk using small amount of samples., Methods: Breast milk samples were extracted by acetonitrile and the lipid substances were removed by freezing under-20 ℃ condition. Then the samples were derivatized with dansyl chloride and analyzed by ultra-performance liquid chromatography-tandem mass spectrometry( UPLCMS/MS). The seperation was performed on an ACQUITY UPLC BEH Phenyl column( 2. 1 mm × 100 mm, 1. 7 μm) with methanol and 0. 1% formic acid in water as mobile phase. The electrospray source was in the positive ion mode and monitored in the multiple reactions monitoring mode. Isotope internal standard dilution technique was used for the quantification analysis. At last, the methodology was studied., Results: The linear range of 8 bisphenols was 0. 010-10. 00 μg/L. The recoveries of the three spiked levels were84. 6%-108. 1%, with the relative standard deviations no more than 12%( n = 6). 30 samples of breast milk were analyzed, in which BPA was detected in 11 breast milk samples, and the concentrations ranged from 0. 13 μg/L to 2. 25 μg/L. BPAF was detected in 1 breast milk sample, and the concentration was 0. 02 μg/L., Conclusion: The established method using a small amount of breast milk is highly sensitive, simple and fast, and can be used for the simultaneous determination of 8 bisphenols in breast milk.

Objective: To revise the standard method for the determination of phenylglyoxylic acid(PGA)and mandelic acid(MA) in urine by ultra-performance liquid chromatography. Methods: The original standard method was evaluated by experiment, and the chromatographic column, the detection limit,quantitation limit and stabilityof the method were studied. Results: The samples were separated by BEH Phenyl(50mm×2.1mm×1.7μm)column and the internal standard working curve method was used. The regression equations were y =3.660 7 x +0.066 3 and y =5.161 2 x -0.007 3 for MA and PGA respectively. Linear correlation coefficients were 0.999 3 and 0.999 1. Linearity ranges were 0.10-1.00 mg/ml,0.04-0.40 mg/ml. The recoveries of PGA and MA were 91.6%-97.1% and 84.3%-99.0%,the precision were 0.9%-4.6% and 0.5%-1.9%. The detection limit and quantitation limit of the method were 1.1 mg/L and 3.7 mg/L for PGA, 5.4 mg/L and 17.9 mg/L for MA. Conclusion: The method uses the phenyh modified chromatographic column, determines the detection limit. The method can improve quantitation limit, the detection accuracy and meet the detection of occupational population samples.

Objectives: To screen for the differential expression proteins in brain tissues of SD rat after diffuse axonal injury （DAI） by isobaric tag for relative and absolute quantification-liquid chromatograph-mass spectrometer/mass spectrometer （iTRAQ-LC-MS/MS）, and to explore potential biomarkers available for the diagnosis of DAI., Methods: Animal models of DAI were established with the Marmarou method as reference, and the subjects were divided into blank control group （ n =4）, sham strike group （ n =4） and fatal strike group （ n =4）, respectively. The proteins in rat brain tissues were detected by iTRAQ-LC-MS/MS, and bioinformatics analysis and verification were performed on the results and screened for the differential expression proteins., Results: A total of 2 016 proteins were identified and quantified. The bioinformatics analysis revealed that the proteins had wide distribution and function, and participated in different biological processes. There were 16 proteins showed differential expression in fatal strike group, including one up-regulated expression protein and 15 down-regulated expression proteins. The results of iTRAQ-LC-MS/MS were confirmed by Western blotting method., Conclusions: Multiple differential expression proteins in rat brain tissues after DAI can be screened by iTRAQ-LC-MS/MS. This not only indicates a research direction for exploring the pathogenesis of DAI, but also provides potential biomarkers available for the diagnosis of DAI., Competing Interests: The authors of this article and the planning committee members and staff have no relevant financial relationships with commercial interests to disclose., (Copyright© by the Editorial Department of Journal of Forensic Medicine)