Search

In healthcare role of biological analyte like uric acid plays a crucial role. Among various antioxidants, uric acid is significant antioxidant that helps in regulating blood-pressure and also reduces the antioxidant stress as well. In this proposed research work different concentration of uric acid were taken for detection using optical absorbance based spectroscopy. After the characterization it was found that as the concentration of uric acid increases, absorbance associated with peak absorbing wavelength also increases. The concentration of uric acid was taken 2, 4 and 8 mg/dl respectively for testing and absorbance found to be 0.75, 1.8 and 2.2 respectively. The sensitivity of device found to be 1 mg/dl.

The feasibility of light-addressed detection and manipulation of pH gradients inside an electrochemical microfluidic cell was studied. Local pH changes, induced by a light-addressable electrode (LAE), were detected using a light-addressable potentiometric sensor (LAPS) with different measurement modes representing an actuator-sensor system. Biosensor functionality was examined depending on locally induced pH gradients with the help of the model enzyme penicillinase, which had been immobilized in the microfluidic channel. The surface morphology of the LAE and enzyme-functionalized LAPS was studied by scanning electron microscopy. Furthermore, the penicillin sensitivity of the LAPS inside the microfluidic channel was determined with regard to the analyte’s pH influence on the enzymatic reaction rate. In a final experiment, the LAE-controlled pH inhibition of the enzyme activity was monitored by the LAPS., Deutsche Forschungsgemeinschaft, Bundesministerium für Forschung und Technologie

Ganoderma (lingzhi) is a famous herbal medicine and edible supplement in oriental countries for a long history. In this study, a simple micellar electrokinetic chromatography (MEKC) method was established for the analysis of nucleosides and bases, the major bioactive components in Ganoderma for the first time. By optimizing the borate concentration, the sodium dodecyl sulfate (SDS) concentration and the pH value of running buffer, 10 nucleosides and bases achieved an ideal separation. In real sample analysis, the developed method was successfully used to determine the 10 target analytes in 23 batches of Ganoderma samples from different regions. Results indicated that contents of 10 investigated analytes in each sample showed obvious variation. The principal components analysis (PCA) and hierarchical cluster analysis (HCA) analysis classified the samples into three groups, and the HCA tree visualized the relationships which was mainly contributed by geographical partition. The results indicated geographical origin to be an important factor that affect the accumulation of nucleosides and bases in Ganoderma. In summary, this study provides a simple and practical strategy for quality assessment and cultivation reference of Ganoderma.

The solid-phase microextraction technique quantifies analytes without considerably affecting the sample composition. Herein, a proof-of-concept study was conducted to demonstrate the use of coated probe electrospray ionization (coated-PESI) and coated blade spray (CBS) as ambient mass spectrometry approaches for monitoring drug biotransformation. The ability of these methods was investigated for monitoring the dephosphorylation of a prodrug, i.e., combretastatin A4 phosphate (CA4P), into its active form, i.e., combretastatin A4 (CA4), in a cell culture medium supplemented with fetal bovine serum. The CBS spot analysis was modified to achieve the same extraction efficiency as liquid-liquid extraction and obtain results in 7 min. Low quantities of target analytes were extracted using coated-PESI, indicating that this technique can be used to perform extractions with only negligible target analyte depletion. Because coated-PESI does not consume any sample, it is the preferred technique in the case of a limited sample volume. Although coated-PESI only extracts small quantities of analytes, it uses the desorption solvent volume of 5–10 pL, resulting in high sensitivity, thus allowing the detection of compounds after only 1 min of extraction. The biotransformation of CA4P into CA4 via phosphatases occurs within the simple matrix, and the proposed sample preparation techniques are suitable for monitoring the biotransformation.

Uric acid is the primary end product of human purine metabolism and has been regarded as a key parameter in urine and blood for monitoring physiological conditions. This paper presents a paper-based biosensor for a quantitative determination of uric acid using electrochemical detection. The working electrode of the biosensor is modified with graphene oxide (GO) and 5-amino-1,3,4-thiadiazole-2-thiol (ATT) by electropolymerizing ATT on the surface of graphene oxide. In this study, cyclic voltammetry (CV) measurements required only 200 μL of analyte solution. The experimental results showed that the oxidation peak current increased as the concentration of uric acid become higher and exhibited a linear relationship in the concentration range of 0.1–10 mM, indicating that this proposed biosensor has high sensitivity. In addition, this biosensor has good selectivity to detect uric acid because ATT has a specific binding with it. In human blood and body fluids, nitrites may be the only factor that can interfere with the detection of uric acid using this proposed biosensor. Nevertheless, uric acid can be discriminated from nitrite in the CV measurement due to different oxidation potentials. Thus, this proposed paper-based biosensor is a promising tool for detecting uric acid in biological samples.

As a neglected member of the platinum group elements, osmium, the metal with the highest density in the earth, is very suitable for the preparation of a peroxidase with high catalytic activity and stability, and can also be associated with the development of a sensor. In this study, we accessed Os nano-hydrangeas (OsNHs) with one-pot synthesis and utilized them in a bifunctional immunosensor that can present both catalytic chromogenic and tinctorial signal for nanozyme-linked immunosorbent assay (NLISA) and lateral flow immunoassay (LFIA) for use in folic acid (FA) detection. In the OsNHs-NLISA, the linear range is from 9.42 to 167.53 ng mL−1. The limit of detection (LOD) is 4.03 ng mL−1 and the IC50 value is 39.73 ng mL−1. In OsNHs-LFIA, the visual cut-off value and limit of detection (v-LOD) are 100 ng mL−1 and 0.01 ng mL−1, respectively. Additionally, the outcome from the specificity and spiked sample analysis offered recovery from the spiked milk powder sample ranging from 93.9 to 103.6% with a coefficient of variation under 4.9%, compared with UPLC-MS/MS for a correlation of R2 = 0.999 and admirable validation. The promising application of the OsNHs can also be used in other bioprobes, and this bifunctional immunosensor analysis mode is suitable for diversified analytes.

Summary Objective The objective of the present study is to develop and validate a simple, rapid stability indicating high performance liquid chromatography method for the simultaneous quantification of metformin, empagliflozin, linagliptin in bulk and pharmaceutical dosage form. Materials and methods The chromatographic separation was achieved on C18 X-bridge phenyl column (250 × 4.6 mm, 5 μm particle size). The pharmaceutical analytes were quantified by diode array detector in HPLC, eluted with acetonitrile and triethylamine (70:30) as mobile phase, monitored at 240 nm over a runtime of 7 min. Results The method was linear in the range of 50–750 μg/mL (r2 = 0.999) for metformin, 0.5–7.5 μg/mL (r2 = 0.999) for empagliflozin, 0.25–3.75 μg/mL (r2 = 0.999) for linagliptin. The percentage recoveries of these 3 drugs were within acceptable limits (99.2–100.8). The method was found to be precise as % RSD Conclusion The validated (as per ICH guidelines) rapid method can be routinely used in quality control lab for the quantification of metformin, empagliflozin and linagliptin in raw materials as well as in pharmaceutical dosage form.

In this work, an innovative colorimetric assay method for the determination of carcinoembryonic antigen (CEA) is developed with aptamer probes utilized as recognition element. DNA hybridization chain reaction (HCR) is used as signal amplification technique, and peroxidase-mimicking hemin/G-quadruplex-assisted catalytic oxidation of 2,2'-azino-bis-3-ethylbenzothiazoline-6-sulfonic acid (ABTS) is deployed as signal reporting mechanism. The detection principle was firstly verified by using gel electrophoresis analysis and absorbance measurements. After condition optimization, a detection limit was theoretically determined as 24.8 ng/mL. Furthermore, the method exhibited good selectivity and satisfactory recovery rates (92.2~108.6%) in serum samples. Moreover, the sensing scheme is easily extended for the detection of other analytes via similar target-aptamer recognition principle. To sum up, this is an enzyme- and label-free, cost-effective yet signal-amplifiable assay scheme for the determination of tumor markers with promising simplicity and selectivity, practical utility, and potential universality. This article is protected by copyright. All rights reserved.

In this study, a fully automated two-dimensional liquid chromatography (2D-LC) system was used for the investigation of the clean-up effect and was compared with a traditional Quick Easy Cheap Effective Rugged and Safe (QuEChERS) liquid chromatography (LC) method. The focus of those investigations was on negative electrospray ionization (ESI) mode. For that purpose, matrix fingerprinting profiles were created. The results allowed a comparison of both methods regarding the estimation of the number and the polarity of detected compounds. Moreover, the results of the present study were compared with the results generated in positive ESI mode (presented in a previous study). Furthermore, the two methods were compared with regard to matrix effects (ME) of 321 analytes in positive ESI mode and 96 analytes in negative ESI mode. In general, fewer compounds could be detected when 2D-LC and/or the negative ESI mode was used. Especially, very polar compounds with m/z values >1000 could be separated and could not be detected anymore when 2D-LC was applied. Furthermore, the best results were obtained for most analytes when 2D-LC was used, although the extent of ME seemed to be higher with 2D-LC.

A simple, selective and rapid ultra performance liquid chromatography-tandem mass spectrometry method was developed and validated for the simultaneous estimation of dolutegravir, lamivudine and tenofovir in bulk and tablet dosage form. Chromatographic separation was attained on Acquity Ethylene Bridged Hybrid (BEH) C18 column (50 × 2.1 mm, 3.5 µm), using a mixture of acetonitrile and 0.1% formic acid in water (60:40, v/v) as a mobile phase at a flow rate of 0.12 mL/min. The total run time of analysis was 3.5 min. The analytes were detected using tandem mass spectrometry, operating in positive ionization and multiple reaction monitoring modes. The method's linearity was determined to be in the range of 10–150 ng/mL with r2 > 0.99. The proposed method was validated as per the International Council for Harmonization (ICH) guidelines, and the results were found well within the acceptance limits. The method was successfully applied for the simultaneous quantification of all the three analytes in the combined tablet dosage form.

Determining trace chromium in complex samples usually requires a sample preparation technique to isolate and extract the analytes from matrices and enrich them for trace analysis. Several methods h...

A rapid and sensitive immunoassay for the simultaneous detection of thiabendazole (TBZ) and carbendazim (CBZ) was developed by using magnetic nanoparticles (MNPs) and two-color upconversion nanoparticles (UCNPs). The anti-thiabendazole and anti-carbendazim antibody were linked to NaYF4:Yb, Tm (emission at 474 nm) and NaYF4:Yb, Er (emission at 542 nm) UCNPs as multicolor signal probe, respectively. The thiabendazole and carbendazim coating antigen were connected to magnetic microspheres as capture probe, respectively. Based on a competitive format, capture probes compete with analytes to combine corresponding signal probes. Under excitation at 980 nm, the formed competitive immune-complex fluorescent signal at 474 and 542 nm indicates the concentration of thiabendazole and carbendazim, respectively. Under the optimal conditions, the 50% inhibiting concentration (IC50) and limit of detection (LOD, IC10) were 2.21 and 0.083 ng/mL for thiabendazole and 1.18 and 0.075 ng/mL for carbendazim, respectively. The average recoveries of thiabendazole and carbendazim in foods, including oyster mushroom, shiitake mushrooms, oranges and orange juice, ranged from 83.6 to 100.9% with the coefficient of variance (CV) of 1.0–9.8% for thiabendazole and ranged from 89.6 to 105.9% with the CV of 2.5 to 9.1% for carbendazim. This multiplexed analysis format has potential applications for rapid, efficient detection of multiple food risk factors.

Microscale-based separations are increasingly being applied in the field of metabolomics for the analysis of small-molecule metabolites. These methods have the potential to provide improved sensitivity, less solvent waste, and reduced sample-size requirements. Ion-pair free microflow-based global metabolomics methods, which we recently reported, were further compared to analytical flow ion-pairing reagent containing methods using a sample set from a urea cycle disorder (UCD) mouse model. Mouse urine and brain homogenate samples representing healthy, diseased, and disease-treated animals were analyzed by both methods. Data processing was performed using univariate and multivariate techniques followed by analyte trend analysis. The microflow methods performed comparably to the analytical flow ion-pairing methods with the ability to separate the three sample groups when analyzed by partial least-squares analysis. The number of detected metabolic features present after each data processing step was similar between the microflow-based methods and the ion-pairing methods in the negative ionization mode. The observed analyte trend and coverage of known UCD biomarkers were the same for both evaluated approaches. The 12.5-fold reduction in sample injection volume required for the microflow-based separations highlights the potential of this method to support studies with sample-size limitations.

A method for analyzing fluoroquinolone antibiotics, viz. enrofloxacin and ciprofloxacin, in chicken meat has been developed with the aim of reducing the total analysis time. Certified reference materials (CRMs) for the chicken meat powder, i.e. KRISS CRM 108-03-003 and KRISS CRM 108-03-004, were used for method development. Isotope dilution ultra-performance liquid chromatography–mass spectrometry (ID-UPLC-MS) was employed for sample analysis. The liquid chromatography (LC) conditions were optimized with an “in-sample addition” method using a trace amount of ethylenediaminetetraacetic acid (EDTA), in which EDTA was not added to the mobile phase but to the sample alone. The optimal EDTA amount was determined, and its influence on the separation of the target analyte was investigated. After the feasibility of the “in sample-addition” approach was confirmed, we attempted to improve the previously established sample pretreatment method by varying the conditions for liquid–liquid extraction and solid phase extraction. The developed method was validated using raw chicken meat for recovery evaluation. The “in-sample addition” method afforded highly improved peak shapes without adversely affecting the LC/MS method performance, and the quantification values of enrofloxacin and ciprofloxacin corresponded well with those obtained using the established method. Consequently, the total analysis time for the determination of enrofloxacin and ciprofloxacin in chicken meat CRM could be reduced by simplifying the sample pretreatment procedure. The developed method delivered better reliability compared to the previously established analytical method. The method will be used for stability monitoring of the chicken meat CRM and the development of other meat CRMs for fluoroquinolone analysis and improved food safety applications.

Background Even though the use of β-agonists in livestock has been banned in many countries, β-agonists abuse is still out of control owing to time-consuming and complicated determination techniques. Objective This study applied ambient thermal desorption electrospray ionization mass spectrometry (TD-ESI/MS) as a new strategy for rapidly screening seven β-agonists. As it does not require pretreatment, this method allows on-site and real-time detection. Method Samples were collected directly using a simple metal probe. Analytes on the probe were desorbed and ionized by TD-ESI, after which analyte ions were detected using a triple quadrupole mass analyser. Results The results showed that a thermal desorption temperature of 320°C and nebulizer pressure of 3 psi demonstrated the highest sensitivity. Excellent linear relationships were obtained in concentrations ranging from 10 to 400 μg/kg. The limit of detection of the method was 1–10 μg/kg with RSDs of 7.2–14.6%. A positive sample was verified using HPLC coupled with triple quadrupole tandem mass spectrometry, consistent with the results from TD-ESI/MS. Conclusion This method was the first to apply TD-ESI/MS to rapid analyse β-agonists in livestock hair and was proven to be accurate, fast, and environmentally friendly. Because qualitative screening for each analysis was completed within approximately 1 min, the method could contribute to preventing non-compliance in the flow of animal-derived food to the market. Highlights This method was a promising method for the rapid screening of β-agonists in livestock hair at any time of breeding without imposing any harm to animal which proven to be a rapid, in situ, and non-destructive detection technique without any pretreatment.

Analytical tests/devices that are used outside laboratory settings are required to have a very simple analytical protocol to get clearance by regulatory authorities. This study describes sink/float magnetic immunoassays, a new type of rapid, mix-and-observe, instrument-free tests for the detection of biomarkers in untreated biological samples that are very simple and might meet the simple-to-use criterion of authorities to be used in the field. These tests can tell whether an analyte is above or below a predetermined level within 25-45 minutes based on the sinking or floating of a mm-sized sphere on the surface of which an immunoassay that uses reporter antibodies conjugated to superparamagnetic nanoparticles is performed. This manuscript describes the theory and proof-of-concept applications of sink/float magnetic immunoassays for the detection of C-Reactive Protein, anti-Treponema pallidum antibodies and E. coli bacteria.

Coffee is the most popular beverage after water and is consumed worldwide. Its consumption in high amount may pose health risks. Moreover, most of the market's available coffee beans products do not mention their proper amount of caffeine. To develop an efficient and reliable method of caffeine extraction in commercial coffee brands, automated solvent extraction was used along with a sensitive, rapid and precise method for simultaneous analysis of caffeine using ultra-high performance liquid chromatography coupled with an ID-X-Orbitrap Mass spectrometer (UHPLC-IDX-Orbitrap-MS). The results showed comparable values to previously published studies. The lowest average amount of caffeine (µg/g) was in the Colombian brand (6.7) and Brazil-CF brand (7.1). The highest average amount of caffeine (µg/g) was in Brazil-C brand (10) and Kenyan brand (10.4). For the rest of coffee beans extract, the caffeine amount was similar varying between 7.7 and 9.7 µg/g. The results demonstrated that the proposed procedure is highly reproducible (with an RSD error of less than 20% for most of the analytes) and the recovery levels of the target compound (i.e., caffeine) varied in the range of 45–88%. Moreover, the limit of detection of caffeine was equal to 1 ng mL−1. This was a pilot study to examine caffeine extraction from different coffee sources and a future study will identify all active compounds.

Aflatoxin B1 (AFB1), as the main metabolite, found in aflatoxin contaminated food is highly toxic and strictly controlled in many countries. Aiming to construct a simplified, highly sensitive, and accurate quantitative detection platform of AFB1 in ordinary conditions, a one-step competitive quantum dot-labeled immunosorbent assay (cQLISA) was developed using biocompatible CdSe/ZnS core/shell quantum dots (QDs). The quantitative detection of AFB1 can be achieved by adding food sample and QD-AFB1 antibody simultaneously, with an analytical range between 1 and 40 ng/mL. The half maximal inhibitory concentration (IC50) of this method is 542 pg/mL and the limit of detection (LOD) is 56 pg/mL for standard samples, demonstrating a twofold improvement in sensitivity compared with that of the commercial enzyme-linked immunosorbent assay (ELISA) test kit. The recovery rates of negative corn spike-in samples range from 87.01 to114.7% (CV

Novel psychoactive substances (NPS) continue to represent a threat to public health and safety. The number of new drugs in the latest emergent synthetic opioid class—the 2-benzylbenzimidazole analogs—also called the nitazenes—has begun to dominate the current new synthetic opioid (NSO) subclass of NPS. We describe a liquid chromatography–tandem quadrupole mass spectrometry method for the quantification of nine analogs and/or metabolites of drugs in this series: isotonitazene, metonitazene, protonitazene, etonitazene, clonitazene, flunitazene, N-desethyl isotonitazene, 5-amino isotonitazene and 4ʹ-hydroxy nitazene in human whole blood, urine, and tissue. Samples were prepared for analysis using a basic liquid–liquid extraction. Chromatographic separation was achieved using a C-18 analytical column. Multiple reaction monitoring mode was used for detection. The calibration range for the analytes was 0.5–50 ng/mL (except for 5-amino isotonitazene, which was 1.0–50 ng/mL). The limit of detection was 0.1 ng/mL, and the limit of quantitation was 0.5 ng/mL. The method had no carryover or interferences. Ionization enhancement was observed but did not affect quantitation. All analytes passed the method validation assessment. Authentic human samples suspected of containing NSOs were obtained from a medical examiner and coroner offices, as well as partnering forensic toxicology laboratories. Isotonitazene was confirmed in 92 blood samples, and its metabolites were confirmed across various matrices. Metonitazene (n = 35), flunitazene (n = 5), protonitazene (n = 3), etodesnitazene (n = 2) and butonitazene (n = 1) were also detected in cases. These newly emerging 2-benzylbenzimidazole analogs were commonly found in combination with NPS benzodiazepines and opioids (e.g., flualprazolam, fentanyl). Nitazene analogs are potent esoteric drugs that may not be identified during routine toxicological screening, and specialized assays based on sensitive instrumentation are needed to accurately characterize these NSOs.

In this study, cyclofructan (CF)-, cyclodextrin (CD)-, and polysaccharide-based chiral stationary phases (CSPs) were exploited in high-performance liquid chromatography (HPLC) for the chiral separations of different clinically and pharmaceutically important compounds. In particular, R-naphthylethyl carbamate CF6 (RN–CF6), 3,5-dimethylphenyl carbamate CF7 (DMP–CF7), neutral beta cyclodextrin (β–CD), 3,5-dimethylphenyl carbamate β–CD (DMP–β–CD), and cellulose tris-(3,5-dimethylphenylcarbamate) (Cellulose–Tris DMP) columns were utilized under isocratic elution. The performance of these CSPs as chiral separation media was evaluated by use of nine analytes: acidic, basic, and amphiprotic. A possible correlation between the functional groups of these analytes and the chiral-recognition ability of each chiral column was also examined. The enantioseparations were optimized by varying different parameters, such as mobile phase additives, column temperature, and flow rate. Finally, a comparison was made between all CSPs, and it was expressed in terms of resolution (RS), efficiency (N), selectivity (α), retention factors (k1′, k2′) and analysis time (tR1, tR2). It was observed that RN–CF6 was the most suitable and efficient CSP for the chiral separation of various types of analytes, including acids, primary and tertiary amines, alcohols, and many neutral compounds. It was the only CSP that provided baseline enantioseparation of thyroxine (RS = 1.6) and cetirizine (RS = 2.0).

Tobacco use is the leading preventable cause of premature disease and death in the United States. Approximately, 34 million U.S. adults currently smoke cigarettes. We developed a method for automated sample preparation and liquid chromatography-tandem mass spectrometry quantitation of 14 tobacco-related analytes: nicotine (NICF), cotinine (COTF), trans-3′-hydroxycotinine (HCTF), menthol glucuronide (MEG), anabasine (ANBF), anatabine (ANTF), isonicoteine (ISNT), myosmine (MYOS), beta-nicotyrine (BNTR), bupropion (BUPR), cytisine (CYTI), varenicline (VARE), arecaidine (ARD), and arecoline (ARL). The method includes automated solid-phase extraction using customized positive-pressure functions. The preparation scheme has the capacity to process a batch of 96 samples within 4 h with greater than 88% recovery for all analytes. The 14 analytes, separated within 4.15 min using reversed-phase liquid chromatography, were determined using a triple-quadrupole mass spectrometer with atmospheric-pressure chemical ionization and multiple reaction monitoring in negative and positive ionization modes. Wide quantitation ranges, within 1.2–72,000 ng/mL, were established especially for COTF, HCTF, MEG, and NICF to quantify the broad range of biomarker concentrations found in the U.S. population. The method accuracy is above 90% while the overall imprecision is below 7%. Finally, we tested urine samples from 90 smokers and observed detection rates of over 98% for six analytes with urinary HCTF and MEG concentrations ranging from 200–14,100 and 60–57,100 ng/mL, respectively. This high throughput analytical process can prepare and analyze a sample in 9 min and along with the 14-compound analyte panel can be useful for tobacco-exposure studies, in smoking-cessation programs, and for detecting changes in exposure related to tobacco products and their use.

The Vitamin D External Quality Assessment Scheme (DEQAS) distributes human serum samples four times per year to over 1000 participants worldwide for the determination of total serum 25-hydroxyvitamin D [25(OH)D)]. These samples are stored at −40 °C prior to distribution and the participants are instructed to store the samples frozen at −20 °C or lower after receipt; however, the samples are shipped to participants at ambient conditions (i.e., no temperature control). To address the question of whether shipment at ambient conditions is sufficient for reliable performance of various 25(OH)D assays, the equivalence of DEQAS human serum samples shipped under frozen and ambient conditions was assessed. As part of a Vitamin D Standardization Program (VDSP) commutability study, two sets of the same nine DEQAS samples were shipped to participants at ambient temperature and frozen on dry ice. Twenty-eight laboratories participated in this study and provided 34 sets of results for the measurement of 25(OH)D using 20 ligand binding assays and 14 liquid chromatography–tandem mass spectrometry (LC–MS/MS) methods. Equivalence of the assay response for the frozen versus ambient DEQAS samples for each assay was evaluated using multi-level modeling, paired t-tests including a false discovery rate (FDR) approach, and ordinary least squares linear regression analysis of frozen versus ambient results. Using the paired t-test and confirmed by FDR testing, differences in the results for the ambient and frozen samples were found to be statistically significant at p

We have identified a clinical need for a sensitive, specific, flexible, comprehensive and affordable analytical technology to efficiently detect polydrug use. In addition, the current standard practice of surveilled urine sampling is uncomfortable for the patient; hence, more patient-friendly sample collection methods are requested. To fill these needs, we have developed and validated a high-throughput liquid chromatography–high-resolution mass spectrometry (LC--HRMS) method for the analysis of drugs of abuse (DoA) in oral fluid (OF). The method covers a panel of 71 substances including traditional DoA, prescription narcotics and new psychoactive substances (NPS), with a guaranteed limit of identification of 99.7%), sensitivity (>99.7%) and specificity (100%). Most analytes had a high process efficiency during the salting-out liquid–liquid extraction sample preparation and no or only a minor matrix effect during the analysis. We have implemented this method in clinical routine and present data from 18,579 OF samples collected during routine patient treatment in mainly psychiatric and addiction clinics in West Sweden between September 2020 and June 2021. Seventy-one percent of the samples were positive and a total of 41,472 DoA findings were detected. Amphetamine (27%), buprenorphine (25%), nordiazepam (18%) and alprazolam (16%) were most prevalent. New psychoactive substances were detected in 189 samples (1.0%). The occurrence of polydrug use was common; 34% of the positive samples contained three analytes or more and 12% six or more. To the best of our knowledge, this is the first method for comprehensive analysis of DoA in OF using LC--HRMS and the largest dataset published on the detection of DoA in OF. With the current complex and variable drug use pattern, this broad, cost-effective and reliable method has largely replaced immunoassay screening in urine in our laboratory.

The development of rapid, reliable, and environmentally friendly analytical methods for food analysis is increasingly required. In this sense, the combination of spectrofluorimetry and second-order calibration is a promising alternative to the determination of naturally fluorescent analytes in food matrices, as compared to the laborious and time-consuming chromatographic methods. This work combined the chemometric second-order method parallel factor analysis (PARAFAC) with spectrofluorimetry aiming to develop a new analytical method to quantify phenylalanine in honey samples. Honey samples of different botanical and geographical origins were diluted with deionized water, and their excitation-emission matrices were recorded between 280–350 nm (excitation) and 360–490 nm (emission). Due to the presence of matrix effect, second-order standard addition was employed. This methodology utilizes the second-order advantage, which allows to quantify an analyte in the presence of uncalibrated/unmodeled interferences. Phenylalanine concentrations were estimated in the range from 5.7 to 32.5 mg kg−1. Method validation was performed by verifying the agreement between the results of the developed method and from an independent methodology based on liquid chromatography. In addition, proper figures of merit were estimated for the proposed method, such as sensitivity, analytical sensitivity, limits of detection, and quantification.

An efficient, sensitive and selective liquid chromatography-tandem mass spectrometry (LC-MS/MS) chiral analysis method was established for determination of chloroquine and hydroxychloroquine enantiomers in rat liver microsomes. Effects of polysaccharide chiral stationary phases and basic additives on chiral separations of two analytes were discussed in detail. Amylose tris(3, 5-dimethylphenylcarbamate)-coated chiral stationary phase showed the best separation performance for them with acetonitrile-diethylamine-ethanol-diethylamine mixture (90:0.1:10:0.1, v/v/v/v) among four chiral stationary phases. Then, multiple reaction monitoring mode was selected as the data acquisition for determination of two pairs of enantiomers. The proposed LC-MS/MS chiral analysis method was validated in terms of linearity, accuracy, precision, and specificity. Good linearity with correlation coefficient over 0.998 was obtained in the concentration range of 0.05-5 μM. Limits of quantification for chloroquine and hydroxychloroquine enantiomers were 5.0 and 1.0 nM, respectively. The recoveries ranged from 81.14% to 111.09%. The intra-day and inter-day relative standard deviation were less than 6.5%. Moreover, concentrations of chloroquine and hydroxychloroquine enantiomers in rat liver microsomes were determined through the proposed LC-MS/MS analysis method. After incubated with rat liver microsomes for 10 min, the enantiomeric factor of hydroxychloroquine decreased from 0.50 to 0.45 (p

Objectives Automated storage and retrieval modules (SRM), as part of total lab automation (TLA) systems, offer tremendous practical and economic benefits. In contrast to manual storage systems, SRMs indicate continuous motion of samples and may leave samples prone to temperature fluctuations. This study investigates analyte stability in serum and heparin plasma within an automated storage module. Methods The stability of 28 common biochemistry analytes was investigated using 57 freshly obtained routine serum samples and 42 lithium-heparin plasma samples. Following baseline measurement, samples were stored at 2–8 °C in the automated SRM of the Accelerator a3600 TLA and reanalyzed at fixed time points (2, 4, 8, 12, 24, 48 and 72 h) on the Abbott Architect c16000 chemistry analyzer. The concentration at each time point was expressed as %-difference to the baseline value and mean results were compared to the criteria for desirable bias derived from the biological variation database. Results Nine of the analytes exceeded the bias criterion within 72 h after initial measurement in either serum samples, plasma samples or both. Lithium-heparin plasma samples showed increasing values for phosphor, potassium and lactate dehydrogenase (LDH), which were only considered stable for respectively 24, 12 and 4 h, glucose was considered stable for 8 h. Electrolyte concentrations and LDH activity significantly increased in serum samples beyond 48 h. Bicarbonate should not be performed as add-on test at all. Conclusions The presented data indicate that the conditions within an SRM have no clinical impact on sample stability and allow stable measurement of routine analytes within 72 h, comparable to manual storage facilities.

Diffusion-ordered nuclear magnetic resonance spectroscopy (DOSY), dubbed chromatographic NMR spectroscopy, can be used to simultaneously distinguish and identify the structures of components in a mixture according to their different diffusion coefficients. In order to improve the resolution of DOSY on the diffusion dimension, a lot of matrices have been developed to expand the application of this technique in mixture analysis. However, there is no matrix to detect the mixture of ionic liquids (ILs). Herein, we introduced a new matrix, poly(sodium-p-styrenesulfonate) (PSSNa), which can be used to fully separate the signals of a mixture of different ILs. The mixture of three imidazolium ILs of 1-butyl-3-methylimidazolium bromide, 1-allyl-3-vinylimidazolium bromide and 1-carboxymethyl-3-methylimidazolium chloride could be fully distinguished by virtue of their different interactions with PSSNa. We also investigated the influences of PSSNa amount, IL concentration and solution pH value on the signal resolution of mixtures. This work provides a scientific reference for the analysis of the other IL analytes.

A new liquid chromatography-electrospray ionization tandem mass spectrometry (LC-ESI-MS/MS) method has been developed and validated for alfuzosin quantification in human plasma using amlodipine as an internal standard (IS). The analyte and IS were extracted using a mixture of diethyl ether-dichloroethane (70 : 30, v/v). The samples were separated on a Waters XBridge HILIC column, where a tandem mass spectrometer with a turbo ion spray interface was used for analytes detection. The chromatographic run time of the method was 4.0 min. The method was linear over the concentration range of 0.20–30 ng/mL for alfuzosin. On evaluating the selectivity of the method, no interference was observed for the two MRM transitions of alfuzosin and MRM transition for amlodipine at their respective retention times. The mean matrix effect for alfuzosin was excellent at 99.9%. The method was carefully tested for linearity, system suitability, precision and accuracy. Intra- and inter-day accuracy and precision were evaluated at three quality control levels (LQC, MQC and HQC). Stability of alfuzosin was evaluated under diverse storage conditions. The percentage accuracy for 1 : 2 diluted samples was 93.2% of their nominal concentration with the coefficient of variation of 5.6%. Hence, a highly precise, accurate, rapid, selective and sensitive LC-ESI-MS/MS method has been developed and validated for the quantification of alfuzosin in human plasma using amlodipine as the internal standard.

Summary Objectives The main aim of the study was to develop an economical, insightful, accurate and simple RP-HPLC-DAD method with high precision and good sensitivity for concurrent determination of Tenofovir disoproxil fumarate, Doravirine and Lamivudine in blended bulk form and their combined tablet form. Material and methods A method with Ascentis C18 (150 × 4.6 mm, 5 μm) column, mobile phase ratio of 0.1% ortho phosphoric acid and Acetonitrile in 70:30 (v/v), 1 mL/min flow rate and detection wavelength of 260 nm was highly proficient in effective separation of all three drugs. The developed method was validated in accordance with ICH specifications. Results The retention times of Doravirine, Lamivudine and Tenofovir disoproxil fumarate observed were 2.4, 2.9, and 3.6 min, respectively. The linear responses were observed for Doravirine, Lamivudine and Tenofovir disoproxil fumarate in the range of 12.5–75 μg/mL, 75–225 μg/mL and 75–225 μg/mL, respectively. The limit of detection and quantification values were calculated to be 0.36 μg/mL and 0.11 μg/mL for Lamivudine, 0.55 μg/mL and 1.66 μg/mL for Tenofovir disoproxil fumarate and 0.03 μg/mL and 0.09 μg/mL for Doravirine. The % RSD values of the intra-day and inter-day precision were calculated in the range of 0.134–1.749. The mean percentage recovery of all three analytes was in the range of 98.85–100.18%. The statistical results of the validation parameters ensured that the method was accurate, specific, and precise with good sensitivity. Investigation of analytes under different stressed conditions ensures the stability of analytes reflecting the stability indication of the method. The developed method has high proficiency in separation of Tenofovir disoproxil fumarate, Doravirine and Lamivudine. The degradation products generated due to stress conditions also separated with good resolution. Conclusion The current method is a stability-indicating assay method consisting of appropriate specificity, accuracy, precision and sensitivity. The developed method has a good potential to be adopted by the pharmaceutical industrial sector.

Background To establish a simple, sensitive, accurate, precise, efficient, economical RP-UPLC method for simultaneous estimation of Doravirine, Lamivudine and Tenofovir disoproxil fumarate in bulk and their combined pharmaceutical formulations. Optimization of Chromatographic separation was achieved on analytical column HSS C18 (100 × 2.1 mm, 1.8 μ) maintained at temperature 30 °C and mobile phase consisting of 0.01 N Potassium dihydrogen orthophosphate buffer (pH-4.8) and acetonitrile in the ratio 60:40 v/v and at a flow rate 0.3 mL/min in isocratic mode. The injection volume was set as 1 µl detection wavelength is 260 nm. The proposed method validation was done as per International Council on Harmonization Q2 (R1) guidelines. Results Doravirine, Lamivudine and Tenofovir disoproxil fumarate were eluted at retention times of 1.2, 1.5, and 1.8 min respectively. The proposed method was identified an excellent linearity over concentration range of 12.5–75.0 µg/mL for Doravirine and 37.5–225.0 µg/mL for Lamivudine and 37.5–225.0 µg/mL for Tenofovir disoproxil fumarate. The percentage relative standard deviation for intra-day and inter-day precision of the present method was less than 2% for Doravirine, Lamivudine and Tenofovir disoproxil fumarate. Accuracy of the present method was evaluated by recovery studies which were in the range of 99.62–99.88% for Doravirine and 98.78–99.44% for Lamivudine and 99.67–100.52% for Tenofovir disoproxil fumarate. The limit of detection and limit of quantification were found to be 0.249 µg/mL and 0.756 µg/mL for Doravirine and 0.24 µg/mL and 0.727 µg/mL for Lamivudine and 0.797 µg/mL and 2.966 µg/mL for Tenofovir disoproxil fumarate. Forced degradation studies were carried out under various stress conditions like acid, base, peroxide, thermal, photo and neutral conditions. Conclusions The present method makes sure about no degraded impurity peak interference at the retention time of analyte peak hence can be applied for quality control investigation of Doravirine, Lamivudine and Tenofovir disoproxil fumarate in bulk and pharmaceutical formulations.

Availability of fentanyl is at a record high with 3138 kg of fentanyl and related substances being seized in 2019. Fentanyl’s high toxicity makes a lethal dose for most mere milligrams. With such a high potency and a consistent rise of abuse, the chances of injury or death of frontline workers increase with every interaction. Development of a non-contact detection method for fentanyl would decrease the chances of a workplace mishap. To aid in the development of a non-contact detection method, target analytes in the vapor profile of fentanyl need to be identified. In order to achieve this goal, semi-quantitative headspace analysis of fentanyl analogs and confiscated fentanyl exhibits was accomplished using solid-phase microextraction and gas chromatography coupled with mass spectrometry (SPME-GC-MS). The vapor signatures of these samples were compared to a previously reported reference-grade fentanyl vapor signature to determine the target analyte(s) for fentanyl detection in the vapor phase. A total of 20 fentalogs and confiscated exhibits, with masses ranging from 2 to 19 mg, were sampled. N-Phenylpropanamide(NPPA) or N-phenethyl-4-piperidone(NPP) was identified as target analytes in 75% of these samples. This is a crucial component for the development of a non-contact detection method for fentanyl.

Narcotic and psychotropic substances are natural, synthetic, or semisynthetic compounds that are present in both solid and liquid illicit products. The alterations effects on the central nervous system related to their use can be psycholeptic, psychoanaleptic, or psychodiseptic and are able to generate tolerance, addiction, or dependence phenomena, creating social and public order problems. In this scenario, the analytical evaluations that aim to determine these analytes in seized nonbiological samples, and which assume the character of judicial evidence, must meet high analytical requirements of reliability, transparency, and procedures uniformity at a national level. For the first time in the literature, the herein validated method is able to provide the simultaneous quantitative determination of 37 of the most common narcotic substances as well as the most commonly used excipients/adulterants found in seized illicit material. Additionally, the validated method can process both solid and liquid samples maintaining the precision and trueness levels (intraday and interday) in accordance with the U.S. Food and Drug Administration and European Medicines Agency international guidelines (

Para Red (PR) and Sudan dyes have been illegally used as colorants to adulterate certain foods by enhancing their red/orange colour. In addition, they are toxic and carcinogenic. This work presents the development of a simple flow injection chromatographic method combined with chemometric tools to perform the determination of PR, Sudan I (SI) and Sudan II (SII) in food samples. The flow chromatographic system consisted of a low-pressure manifold coupled to a reverse phase monolithic column. A Partial Least Square (PLS) model was applied to resolve overlapped absorption spectra registered for each dye at the corresponding retention time. The relative errors of calibration (RMSECV, %) were 0.49, 0.85 and 0.23, and the relative errors of prediction (RMSEP, %) were 1.12, 0.75 and 0.33 for PR, SI and SII, respectively. The residual predictive deviation (RPD) values obtained were higher than 3.00 for all analytes. The method was successfully applied to quantify the dyes in six different commercial spices samples. The results were compared with the HPLC reference method concluding that there were no significant differences at the studied confidence level (α = 0.05). The proposed method can be used to rapidly determine the analytes in a simple, reliable, low-cost and environmentally-friendly manner. SUPPLEMENTARY INFORMATION: The online version contains supplementary material available at 10.1007/s13197-021-05299-8.

Field-deployable diagnostics based on cell-free systems have advanced greatly, but on-site quantification of target analytes remains a challenge. Here we demonstrate that Escherichia coli lysate-based cell-free biosensors coupled to a personal glucose monitor (PGM) can enable on-site analyte quantification, with the potential for straightforward reconfigurability to diverse types of analytes. We show that analyte-responsive regulators of transcription and translation can modulate the production of the reporter enzyme β-galactosidase, which in turn converts lactose into glucose for PGM quantification. Because glycolysis is active in the lysate and would readily deplete converted glucose, we decoupled enzyme production and glucose conversion to increase the end point signal output. However, this lysate metabolism did allow for one-pot removal of glucose present in complex samples (like human serum) without confounding target quantification. Taken together, our results show that integrating lysate-based cell-free biosensors with PGMs enables accessible target detection and quantification at the point of need.

An online method involving transient electrokinetic dosing and ITP with neutralization reaction boundary (NRB) and/or carrier ampholyte-free isoelectric focusing (CAF IEF) was developed for the preconcentration, preseparation, and analytical determination of glyphosate in aqueous samples containing low concentrations of the analyte of interest. Various parameters were investigated in the framework of an optimization study with the aim of achieving the maximum concentration limit of detection (cLOD) decrease in minimum time. The proposed method used CAF IEF and/or ITP with NRB. The sample was dosed to the column on the stationary reaction boundary (CAF IEF) and/or moving reaction boundary (ITP with NRB), whereat a sharp pH step exists. Here, charge reversal was due to the ampholytes, and/or acid accumulation occurred because of charge loss. Similarly, the accumulated sample was mobilized with TE and analyzed using classical ITP in the second analytical column. Glyphosate (GLY), the analyte of interest, was chosen as a model substance for ITP with NRB and preconcentration as well as focusing preconcentration and CAF IEF using the asymmetric purpose-built NRB. On one side of the asymmetric boundary was the zone of acidic pH; while the opposite side comprised a neutral/basic non-conductive zone of the ampholyte-in this case, GLY. Such an arrangement enables the use of a lower pH on the acidic side, which allows the focusing of strongly acidic ampholytes and the accumulation of weak acids. The electrolyte composition and the dosing time were optimized, and a 14-fold accumulation was achieved in 25 min compared to that by classical ITP and a 180-fold accumulation was achieved through CAF IEF and preconcentration with a glyphosate sample. Both methods are simple and can be conducted using all commercial ITP systems.

Humans are exposed to a broad range of organic chemicals. Although targeted gas chromatography mass spectrometry techniques are used to quantify a limited number of persistent organic pollutants and trace organic contaminants in biological samples, nontargeted, high-resolution mass spectrometry (HRMS) methods assess the human exposome more extensively. We present a QuEChERS extraction for targeted and nontargeted analysis of trace organic contaminants using HRMS and compare this method to a traditional, cartridge-based solid-phase extraction (SPE). Following validation using reference and spiked serum samples, the method was applied to plasma samples (n = 75) from the Prospective investigation of Obesity, Energy, and Metabolism (POEM) study. We quantified 44 analytes using targeted analysis and 6247 peaks were detected using the nontargeted approach. Over 90% of targeted analytes were at least 90% recovered using the QuEChERS method in spiked serum samples. In nontargeted analysis, 84% of the peaks were above the method detection limit with area counts up to 3.0 × 105 times greater using the QuEChERS method. Of the targeted compounds, 88% were also identified in the nontargeted analysis. We categorized the 4212 chemicals assigned an identity in using EPA’s CompTox Dashboard and 1076 chemicals were found in at least one list. The category with the highest number of chemicals was “androgen or estrogen receptor activity.” The findings demonstrate that a QuEChERS technique is suitable for both targeted and nontargeted analysis of trace organic contaminants in biological samples.

Method analytical validation and verification is crucial in routine qualitative and quantitative analysis. Analysis laboratory need objective evidences about specific parameters in their drugs/analytes or drugs metabolites in matrices biology. Urine is the most preferable matrix biology for determining drugs metabolites especially in drug abuses cases because urine’s sampling process is not invasive. There are many methods extracting drugs in urine, especially methamphetamine and amphetamine as those two analytes are excreted via urine. This study presented method verification for determination of methamphetamine and amphetamine in urine using Gerstel® automated Disposable Pipette Extraction (DPX) Multipurpose Sampler (MPS). Result of this study showed that retention time of methamphetamine is in minute 6.21, and amphetamine is in minute 3.15. Methampethamine’s curve displayed a coefficient of determination r2=0,9999 with the equation y=170,19x+33183. The equation of amphetamine showed y=44390x – 17513 with coefficient of determination r2= 0,9974. Limit of detection (LOD) of methamphetamine in urine is 59,73 ppb, and LOD of amphetamine is 36 ppb.

To take full advantage of the reagent- and label-free sensing capabilities of electrochemical sensors, a frequent and remaining challenge is interference and degradation of the sensors due to uncontrolled pH or salinity in the sample solution or foulants from the sample solution. Here, we present an oil-membrane sensor protection technique that allows for the permeation of hydrophobic (lipophilic) analytes into a sealed sensor compartment containing ideal salinity and pH conditions while simultaneously blocking common hydrophilic interferents (proteins, acids, bases, etc.) In this paper, we validate the oil-membrane sensor protection technique by demonstrating continuous cortisol detection via electrochemical aptamer-based (EAB) sensors. The encapsulated EAB cortisol sensor exhibits a 5 min concentration-on rise time and maintains a measurement signal of at least 7 h even in the extreme condition of an acidic solution of pH 3.

Achieving simultaneous determination of antibiotic multiresidues in environmental waters by solid phase extraction (SPE) coupled with ultra-high-performance liquid chromatography tandem mass spectrometry (UHPLC-MS/MS) with detection limits ≤ ng L-1 is still a huge challenge. Moreover, the offline SPE procedure was performed manually, costly, and time-consuming, while the online SPE required precision pretreatment instruments that require highly-skilled personnel. In this paper, a fully automated SPE coupled with UHPLC-MS/MS method was developed for analysis of antibiotics (sulfonamides, quinolones, and macrolides) in water matrices. Sample preparation optimization included SPE materials and configuration (HLB disks), sample volume (500-1000 mL), and pH (pH = 3) with a flow rate at 2~5 mL min-1, and an elution procedure with 2 × 6 mL methanol, and 2 × 6 mL acetone. Meanwhile, the parameters for UHPLC-MS/S detection of analytes were optimized, including LC retention time, and MS parameters. The instrumental limits of detection (LOD) and quantification (LOQ) of analytes ranged from 0.01-0.72 μg L-1 and 0.05-2.39 μg L-1, respectively, with satisfactory linear calibration (R2 > 0.995) and precision (< 9.9%). Recoveries in spike samples ranged between 77.5-104.9% in pure water, 59.4-97.8% in surface water (SW), and 58.2-108.6% in wastewater effluent (WWE) with relative standard deviations ≤ 12.8%. The matrix effects observed for most analytes were suppression (0-28.1%) except for five analytes having presented enhancement (0-14.6 %) in SW or WWE. This method can basically meet the needs of trace antibiotic residues detection in waters, with examples of concentrations of detected antibiotics being lower than LOQ (LLQ) -94.47 ng L-1 in WWEs and LLQ-15.47 ng L-1 in SW in the lower reaches of the Yangtze River Basin.

A stability-indicating UV spectroscopic and high-performance liquid chromatography (RP-HPLC) method is developed for the quantification ofPioglitazone, Glimepiride & Metformin Hydrochloride drug substances. UV spectroscopic method was developed and validated, the wavelength selected for simultaneous estimation were 226nm for pioglitazone, 229nm for glimepiride and 232nm for metformin hydrochloride. The isosbestic point found for the analysis was 229nm. Selected mobile phase was a combination of methanol and water with a ratio of 70% Methanol and 30 % HPLC water with the flow rate of 0.85ml/min. The analyte was analysed on the C18 HPLC column having the pore size of 5 microns at room temperature. The method is validated according to ICH guidelines, the retention time of about 4.0min for metformin, 5.5min for Pioglitazone and 6.8min for Glimepiride was observed. The linearity range with regression co-efficient for Pioglitazone, Glimepiride & Metformin Hydrochloride is 3-15 ?g/mL,0.4-1.2 ?g/mL and 100-500 ?g/mL and 0.9998, 0.9991, 0.9991 respectively. Keywords: Glimepiride, Pioglitazone, Ruggedness

The abuse of antibiotics in modern life and aquaculture has become a worldwide problem. Trace amounts of antibiotics discharged into natural water are increased in organisms through bioaccumulation and ultimately harm human health. Herein, we report a metal-tagged CRISPR/Cas12a bioassay and apply it to an ultrasensitive and highly selective evaluation of antibiotics bioaccumulation in wild fish samples. We integrated an element-tagging report probe and collateral cleavage activity of CRISPR/Cas12a. With the recognition and capture of target kanamycin by a "locked-activated" system, the activator strand was subsequently released to activate the collateral cleavage activity of Cas12a, followed by the cleavage of free Tm-Rep. After SA-MB capture, the biotin terminal was modified, and the uncleaved probe of Tm-Rep was removed. The acidized supernate containing the element tag fragment could be directly detected with 169Tm isotope monitoring by inductively coupled plasma mass spectrometry (ICPMS). With CRISPR/Cas12a biosensing and metal isotope detection by ICPMS, ultrasensitive and fast antibiotics analysis was realized with multiplex detection potential. Taking kanamycin as a modal analyte, a limit of detection as low as 4.06 pM was provided in a 30 min detection workflow. Besides, the bioaccumulation effect of kanamycin in a wild fish sample was also evaluated using the proposed strategy. We investigated the geographical distribution with Pseudorasbora parva samples collected in four different locations along a 600 km stretch of the Yangtze River. In addition, the bioaccumulation kinetics of antibiotics was evaluated in serum, muscle, and liver tissues of Pseudorasbora parva with 7 days of continuous feeding in a kanamycin-enriched environment.

Sodium dodecyl sulfate (SDS) provides numerous benefits for proteome sample preparation. However, the surfactant can be detrimental to downstream mass spectrometry analysis. Although strategies are available to deplete SDS from proteins, each is plagued by unique deficiencies that challenge their utility for high-throughput proteomics. An optimal approach would rapidly and reproducibly achieve less than 10 ppm residual SDS while simultaneously maximizing analyte recovery. Here, we describe improvements to a simple electrokinetic device termed transmembrane electrophoresis, which we previously reported for automated, rapid SDS depletion of proteome samples. Voltage-driven transport of SDS across a molecular weight cutoff membrane is enhanced at higher electric fields, which is herein achieved by integrating an active cooling mechanism to mitigate the impacts of Joule heating. We report 99.9% reduction of SDS (final concentration5 ppm) in 5 min. The device is employed in a detergent-based proteomic workflow for analysis of an enriched yeast membrane proteome extract, demonstrating quantitative protein recovery (98%) and increasing the number of identifications by liquid chromatography-tandem mass spectrometry.

An international robin round was carried out to validate a method for the quantification of 2-monochloropropane-1,3-diol (2-MCPD), 3-monochloropropane-1,2-diol (3-MCPD) and 2,3-epoxy-1-propanol (Glycidol) being present as fatty acid esters in plant-based food emulsifiers. The evaluated method was a modification of the American Oil Chemist´s Society (AOCS) Official Method Cd29b-13. Briefly, this method consists from parallel analysis of two sample aliquots that are spiked with different sets of internal standards. Mild alkaline interesterification overnight in the freezer releases the core analytes. Reaction stop and glycidol conversion into monobromopropanediol (MBPD) is realised by addition of acidified sodium bromide solution. Subsequently, matrix removal and analyte extraction are achieved by two liquid/liquid (l/l) extraction steps. After derivatisation with phenylboronic acid (PBA) the final extracts are analysed by gas chromatography-mass spectrometry (GC-MS). Quantification is carried out by internal one-point-calibration. 6 laboratories from 4 European countries participated in the trial and reported 8 data sets for 10 test materials (mono- and diacylglycerides as well as polyglycerol polyricinoleates) that were analysed as blind duplicates, giving a total of 20 samples. Result outliers were eliminated according to accepted standards. At 2-MCPD levels above 0.02 mg/kg, 3-MCPD levels above 0.06 mg/kg and glycidol levels above 0.22 mg/kg repeatability (RSDr) ranged from 1.5 % to 24.9 %, reproducibility (RSDR) ranged from 7.8 % to 29.0 % and HORRATR-values ranged from 0.5 to 1.7. The tested method showed to be suitable for the determination of 2-MCPD, 3-MCPD and glycidol in food emulsifiers consisting from mono- and diacylglycerides as well as polyglycerol polyricinoleates.

A simple, sensitive and accurate liquid chromatography tandem mass spectrometric method has been developed and validated for determination of Tofacitinib in human plasma. The method was developed on Agilent Zorbax SB-C8 150×4.6 mm, 5 µm column using 10mM ammonium formate: acetonitrile (40:60 v/v) mobile phase for Chromatographic separation of Tofacitinib. The Tofacitinib and Tofacitinib- C3 were monitored by electrospray ionization in positive ion multiple reactions monitoring mode to detect the Tofacitinib at mass/charge 313.200/149.200 and Tofacitinib-13C3 (Internal Standard) at 316.500/149.200. Liquid-liquid extraction was employed in the extraction of analytes from human plasma. Both drug and internal standards were stable in plasma samples. The proposed method was validated as per international council of harmonization guidelines over a linear concentration range of 0.2ng/mL to 100.0ng/mL with a correlation coefficient (r) of ≥ 0.9983. Bioavailability and Bioequivalence studies of tofacitinib in biological samples can be achieved by analyzing them using the validated developed method. This study plays a key role in determining routine therapeutic drug monitoring of tofacitinib drug.

Poly(dimethylsiloxane)-based thin-film sorbent sheets (SPMESH) have previously been used for parallel headspace (HS) extraction prior to direct analysis in real-time mass spectrometry (DART-MS) for rapid quantitation of odorants in complex matrices. However, HS-SPMESH extraction is poorly suited for less volatile odorants, e.g., volatile phenols. This report describes modifications to the previous SPMESH extraction device, which make it amenable to parallel extraction of low-volatility analytes from multiwell plates under direct immersion (DI) conditions. Optimization and validation of the DI-SPMESH-DART-MS approach were performed on four volatile phenols (4-ethylphenol, 4-ethylguaiacol, 4-methylguaiacol, and guaiacol) of relevance to the quality of grape juices. Negative-ion mode DART-MS spectra showed a series of oxygenated adducts [M + nO - H]- for all analytes, but isobaric interferences could be limited for three of the four analytes by selecting an appropriate MS/MS transition. Signal suppression from nonvolatiles (sugars, acids) could be overcome by a rinse step. DI-SPMESH-DART-MS analysis of 24 samples could be performed in ∼45 min (30 min extraction, 16 min DART analysis) with 0.5-3 μg/L detection limits in aqueous and model juice solutions. In real grape juices (n = 5 cultivars), good accuracy (72-137%) could be achieved for two of the four volatile phenols initially investigated, 4-ethylphenol and 4-ethylguaiacol. However, poor accuracy was observed for guaiacol in some cultivars, and 4-methylguaiacol could not be quantitated due to interferences with other volatile phenols. Despite these limitations, DI-SPMESH-DART-MS/MS may be useful for prescreening a large number of samples prior to more selective conventional analyses.

Capillary electrophoresis coupled online with mass detection is a modern tool for analyzing wide ranges of compounds in complex samples, including urine. Capillary electrophoresis with mass spectrometry allows the separation and identification of various analytes spanning from small ions to high molecular weight protein complexes. Similarly to the much more common liquid chromatography-mass spectrometry techniques, the capillary electrophoresis separation reduces the complexity of the mixture of analytes entering the mass spectrometer resulting in reduced ion suppression and a more straightforward interpretation of the mass spectrometry data. This review summarizes capillary electrophoresis with mass spectrometry studies published between the years 2017 and 2021, aiming at the determination of various compounds excreted in urine. The properties of the urine, including its diagnostical and analytical features and chemical composition, are also discussed including general protocols for the urine sample preparation. The mechanism of the electrophoretic separation and the instrumentation for capillary electrophoresis with mass spectrometry coupling is also included. This review shows the potential of the capillary electrophoresis with mass spectrometry technique for the analyses of different kinds of analytes in a complex biological matrix. The discussed applications are divided into two main groups (capillary electrophoresis with mass spectrometry for the determination of drugs and drugs of abuse in urine and capillary electrophoresis with mass spectrometry for the studies of urinary metabolome).

This study aimed to validate a modified QuEChERS method followed by ultra-high performance liquid chromatography–tandem mass spectrometry to determine 79 new psychoactive substances (NPS) and other drugs in blood and urine. Prescription drugs (n = 23), synthetic cathinones (n = 13), phenethylamines (n = 11); synthetic cannabinoids (n = 8), amphetamines (n = 7) and other psychoactive substances (n = 17) were included in the method. 500 µL of biological fluid was extracted with 2 mL of water/ACN (1:1), 500 mg of anhydrous MgSO4/NaOAc (4:1) added, followed by a supernatant cleanup with 25 mg of primary secondary amine and 75 mg of anhydrous MgSO4. Quantification was done using matrix-matched calibration curves and deuterated internal standards. The method was satisfactorily validated for blood and urine at limit of quantifications ranging from 0.4 to 16 ng/mL, and applied to the analysis of 54 blood (38 postmortem and 16 antemortem) and 16 antemortem urine samples from 68 forensic cases. All urine samples and 59.3% of the blood samples were positive for at least one analyte. Twenty-two analytes were detected in at least one biological sample, including the synthetic cathinones ethylone (222 ng/mL, antemortem blood), eutylone (246 and 446 ng/mL, urine), and N-ethylpentylone (597 and 7.3 ng/mL, postmortem and antemortem blood, respectively). The validated method was shown to be suitable for the analysis of blood and urine forensic samples and an important tool to collect information on emerging drug threats and understanding the impact of NPS and other drugs in poisoning cases.

Phenol is used as a preservative in a number of biological products. Methods that are used for quantitative determination of phenol differ a lot. Current requirements for accredited laboratories include continuous internal quality control. Reference standards with a certified content of the analyte are an effective metrological tool for ensuring such control. The aim of the study was to develop and certify reference standards for phenolic content in biological products, based on comparison of results obtained by GLC, HPLC, spectrophotometric, and colorimetric methods. Materials and methods: diluent for allergens by (candidate reference standard), 2.5 and 5 mg/mL phenol solutions, and 2.5 mg/mL 2-phenoxyethanol solution were used in the study. The experiments were performed using spectrophotometric, colorimetric, HPLC, and GLC procedures. The statistical analysis of results included calculation of the arithmetic mean, standard deviation, coefficient of variation, and analysis of variance with Student’s t-test and Fisher’s F-test. Results: the results of phenolic content determination by the spectrophotometric, colorimetric, and HPLC methods were statistically comparable. The F value obtained for equal sample sizes (n = 40) was F = 0.9343, given the critical value Fcrit = 3.96. A reference standard certified by one of these methods can be used to control the consistency of phenol determination by a relevant method. The results of phenolic content determination by the GLC method showed statistically significantly differences: F = 17.47, given Fcrit = 3.96, which demonstrated the need for certification of another reference standard. Conclusions: two reference standards were certified in the study: reference standard 42-28-449 with the certified phenolic content of 2.56‒3.32 mg/mL, to be used with the spectrophotometric, colorimetric, and HPLC methods; and reference standard 42-28-451 with the certified phenolic content of 2.92‒3.28 mg/mL, to be used with the GLC method.

Polyoxyethylene glycerol ricinoleate (PGR) serves as a solubilizer/emulsifier that is commonly used in pharmaceutical formulations despite being associated with severe anaphylactoid hypersensitivity reactions. Cremophor EL® (CrEL) is the most representative PGR produced from reacting ethylene oxide with castor oil. To help clarify the cause of side effects and potentially improve the safety of PGR-based drug delivery vehicle, we have developed separate but related analytical methods for the quantitation of CrEL and its main metabolites, glycerol ethoxylate (GE) and ricinoleic acid (RA). Since CrEL and GE are highly disperse mixtures of polymers that are not amenable to analysis by conventional liquid chromatography-tandem mass spectrometry (LC-MS/MS), we used liquid chromatography-triple-quadrupole-time-of-flight mass spectrometry (LC-Q-TOF MS) combined with product ion data acquisition by MSALL and sequential window acquisition of all theoretical fragments mass spectrometry (SWATH MS), respectively to perform the analysis. In contrast, RA is a single molecular entity that could be readily analyzed using conventional LC-HR MS/MS. Selection of specific fragment ions for CrEL, GE, RA and their internal standards enabled a precise quantitation of such a complex analytes system in rat plasma after a single and simple sample preparation method. Assay validation indicated linearity for CrEL, GE and RA over the concentration ranges 0.2~20.0 μg/mL, 0.1~10.0 μg/mL and 0.1~20.0 μg/mL, respectively with satisfactory results for other validation parameters. A subsequent pharmacokinetic study involving single intravenous 200 mg/kg injections of CrEL to rats showed the methods enable comprehensive and high throughput quantitation of CrEL and its metabolites in a biological matrix. Our combination of assays provides effective application in investigating the cause of the hypersensitivity reaction of PGR and potentially to improve its safety for using as a vehicle in drug formulations.