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Microplastics (MPs) in the air are one of the major concerns due to their possible health risks. In addition, airborne microplastics act as a carrier for several toxic air pollutants and cause carcinogenic, mutagenic and teratogenic effects. Nylon 66 is one of the most abundant MPs in the microenvironments. In this study, we report an optimized method for the quantification of nylon 66 MPs present in the fine particulate matter (PM2.5) using high-performance liquid chromatography coupled to tandem mass spectrometry (HPLC-MS/MS). The optimized method exhibited excellent linearity, recovery rates, intraday and interday precision and sensitivity. The optimized method was deployed to carry out a pilot study to measure the mass concentrations of nylon 66 microplastics present in the inhalable fraction of particulate matter collected in a shopping complex. The observed mass concentrations of nylon 66 MPs in this study are in the range from 0.30 ng m−3 to 4.37 ng m−3. This study demonstrates the presence of inhalable fraction of nylon 66 MPs in the indoor environment and their mass concentrations were determined using HPLC-MS/MS. [ABSTRACT FROM AUTHOR]

This study established a simple, rapid, and sensitive ultra-high-performance liquid chromatography-tandem mass spectrometry (UHPLC-MS/MS) method for the simultaneous quantification of contezolid and its major metabolite M2 in human plasma and cerebrospinal fluid (CSF). We used isotope-labeled internal standards (IS) along with protein precipitation to efficiently eliminate impurities. The ion transition was m/z 409.1 → 269.1 for contezolid, m/z 414.1 → 269.0 for contezolid-d5, m/z 445.1 → 385.1 for M2, and m/z 450.2 → 390.1 for M2-d5. The flow rate was 0.4 mL/min with a run time of 2.5 min. Validation results demonstrated that the calibration range was 10–5000 ng/mL for contezolid, and 5–2500 ng/mL for M2 in plasma and CSF. Both analytes exhibit excellent linear relationships (all R2 ≥ 0.99). Intra- and inter-batch accuracy and precision for all quality control (QC) levels were within ± 15%, including the lower limit of quantification (LLOQ). The recoveries of contezolid and M2 were 92.60–100.4% and 92.26–99.61% in plasma and 93.33–99.19% and 91.31–98.21% in CSF, respectively. The matrix effects for contezolid and M2 were 97.20–110.3% and 98.27–105.47% in plasma and 105.25–112.99% and 103.35–109.84% in CSF, respectively. The coefficients of variation (CV%) were ≤ 12.58%. Conteozolid and M2 remained stable in plasma and CSF. This study has established a simple and accurate method for determining contezolid and M2 in human plasma and CSF, making it a valuable tool for monitoring the efficacy of central nervous system (CNS) drugs. [ABSTRACT FROM AUTHOR]

Coumarin and furocoumarins characterization in cosmetics plays an important role in protecting consumer health. The analytical technique mostly employed for the analysis of these molecules is certainly liquid chromatography coupled to photodiode array or mass spectrometer detectors. The aim of this article was to investigate on the oxygen heterocyclic compounds content in fifty hydro alcoholic fragrances using a fast, sensitive and eco-friendly liquid chromatography coupled to a triple quadrupole mass spectrometer detector analytical method without any sample pre-treatment. To the best of the author’s knowledge, this is the first research article on the quantification of thirty-six oxygen heterocyclic compounds in hydro alcoholic fragrances in less than 4 min and with the use of water/ethanol as mobile phase. Thanks to the good performance of the analytical method used, this can be proposed among the routine methods for the quality control of cosmetics and finished products. [ABSTRACT FROM AUTHOR]

A method for determining human epidermal growth factor (hEGF) in cosmetics was developed using solid-phase extraction with high-performance liquid chromatography – tandem mass spectrometry. The sample was extracted and purified by a mixed anionic solid-phase extraction column (MAX), and the eluent was passed through a nylon filter membrane into a polypropylene vial. The matrix-matched external standard method was used to quantify the analyte in multi-reaction monitoring mode. The analyte had an excellent peak shape within 11 min with a linear range from 5 to 80 ng/mL and a linear correlation coefficient (r) of 0.9995. The limit of detection and limit of quantification were 0.75 and 2.5 μg/kg, respectively. The recovery of the target was from 81.5% to 88.8%, and the relative standard deviation was between 1.16% and 5.07%. The results met the International Organization for Standardization 12787 standard. The established method was successfully applied to 30 cosmetic samples. The proposed method is sensitive, accurate, reliable, and suitable for the quantitative confirmation of hEGF and monitoring its illegal addition to cosmetics. [ABSTRACT FROM AUTHOR]

A simple method for the determination of 19 types of phthalate acid ester plasticizers in raw textile solid waste has been developed by employing ultrasonic extraction coupled with gas chromatography – tandem mass spectrometry (GC-MS/MS). The evaluation of the plasticizers in several textile solid wastes showed that the levels were high, especially dimethylglycol phthalate. The extraction solvent, ultrasonic time, and ultrasonic temperature were optimized. Hexane was adopted as the extraction solvent, and ultrasonic extraction was performed at 20 °C for 30 min. A linear relationship from 0.02 to 1000 ng/mL was obtained with correlation coefficients(r) greater than 0.996. The limits of quantitation were from 0.08 to 30.70 µg/L based upon a signal-to-noise ratio (S/N) of 10. The recoveries were from 90.1% to 108.9% and the relative standard deviation between 0.78% and 9.43%. The method can be used for rapid screening and quantitative analysis of textile solid waste due to the simple, sensitive, and accurate assay. [ABSTRACT FROM AUTHOR]

Per- and polyfluoroalkyl substances (PFAS) analysis has become crucial due to their presence in the environment, their persistence and potential health risks. These compounds are commonly used in food contact materials (FCM) as a coating to provide water and grease-repellent properties. One of the pathways for PFAS to enter the human body is either through direct consumption of contaminated food or indirectly through migration from FCM into food. The purpose of this study was to investigate where the initial contamination of paper FCM occurs. We analysed paper material consisting of fresh fibre and secondary materials, intended to produce food packaging for the presence of PFAS. The samples were extracted and analysed for 23 different PFAS substances using the targeted approach with LC tandem mass spectrometry (LC-MS/MS). This analytical technique detects specific, easily ionisable PFAS with high sensitivity. However, one drawback of this approach is that it allows the identification of less than 1% of the PFAS known today. For this reason, we used combustion ion chromatography (CIC) to determine the content of extractable organic fluorine compounds (EOF) and compare it to the total fluorine content. The targeted analysis using LC-MS/MS measured an average sum concentration of PFAS of 0.17 ng g−1 sample. Our research shows that the primary PFAS contamination happens during the recycling process since all of the samples in which the targeted PFAS were measured belonged to the secondary material. The most frequently detected analytes were PFOA and PFOS, detected in 90% and 62% of the samples, respectively, followed by PFBS (in 29% of the samples). CIC showed that measured PFAS via LC-MS/MS amount to an average of 2.7 × 10−4% of total fluorine content, whereas the EOF was under the LOD in all of the measured samples. This result highlights the complexity of the accurate determination of PFAS compounds, displaying what kind of information the chosen methods provide. [ABSTRACT FROM AUTHOR]

A rapid and simple magnetic solid phase extraction-liquid chromatography-tandem mass spectrometry method is reported to determine vancomycin in human plasma. The Fe3O4@SiO2 nanocomposite was prepared using silica nanoparticles obtained from rice husk waste and its modification using ammonia solution to obtain a Fe3O4@SiO2-NH2 nanohybrid as a new sorbent. The structure and morphology of the sorbent were characterized by X-ray diffraction, field emission scanning electron microscopy, and Fourier transform infrared spectroscopy. The nanosorbent was successfully used in magnetic solid phase extraction without hazardous solvents in 9 min with analysis by high-performance liquid chromatography – tandem mass spectrometry. Under the optimized conditions, the method provided a linear range from 10 to 1000 ng mL−1. The intra-day (n = 3) and inter-day precision (n = 3 working days) were below 10% relative standard deviation. The developed procedure was employed for determining vancomycin in human plasma with recoveries from 84.0 to 109.5% for spiked samples. [ABSTRACT FROM AUTHOR]

Three chromatographic procedures were investigated regarding their potential for the quantification of aniline and 19 of its methylated and chlorinated derivatives in groundwater. These methods were based on liquid-liquid-extraction in combination with gas chromatography and single quadrupole mass spectrometry (GC/MS) according to German standard DIN 38407–16:1999 and its extension using tandem mass spectrometry (GC/MS-MS), both following liquid–liquid extraction, and as third alternative the direct injection of the water sample into a liquid chromatograph coupled to tandem mass spectrometry (LC/MS-MS). Results were compared using fortified water and real-world contaminated groundwater used in an interlaboratory comparison. It could be shown that GC/MS and GC/MS-MS yielded results deviating less than 10% from each other, while all three procedures displayed quantification results deviating less than 15% from the intercomparison reference values in case of each analyte in the concentration range between 1 and 45 µg L−1. Though GC/MS-MS displays a ten-fold higher sensitivity than single quadrupole GC/MS, the precision of both methods in the concentration range was similar. LC/MS-MS has the advantage of no further sample preparation due to direct injection and leads for methylanilines and meta-, para-substituted chloroanilines to results sufficiently equivalent to the standardised GC/MS method. However, LC/MS-MS is not suitable for ortho-chloroaniline derivatives due to significantly lower ion yields than meta- and para-substituted chloroanilines. [ABSTRACT FROM AUTHOR]

Orange oil is considered the largest produced essential oils worldwide due to its unique properties. Pesticide residues in orange oil are expected to be much higher than the original fruit due to orange peel's cold-pressing during orange oil production. These residuesmaycause various health problems if consumed. The purpose of our study was to optimize and compare four multi-residues extraction methods (dilution, QuEChERS, ethyl acetate, and mini-Luke) for analysis of 387 pesticides in orange oil using LC-MS/MS and GC-MS/MS. To our knowledge, this is the first report on the use of ethyl acetate and the mini-Luke method for the analysis of orange oil. The comparison was based on recoveries, matrix effect, and the amount of co-extract matrix. The optimum mean recoveries were obtained by the ethyl acetate method, which successfully analyzes 371 out of 387 pesticides with acceptable recovery (70–120%). It also showed a narrow recovery distribution in the range of 90–110% for 69% of all studied pesticides. Regarding the matrix effect, the QuEChERS method gave the highest number of pesticides with an in significant matrix effect (80–120%) for both LC and GC amenable pesticides. The least amount of co-extract matrix components according to GC-MS/MS scan and gravimetric analysis has been achieved by the QuEChERS method. In conclusion, the Ethyl acetate method gives acceptable recovery for a wide range of pesticides with a narrow recovery distribution and a moderate amount of co-extract matrix. While the QuEChERS method provides better selectivity and cleaner extract but with a narrow scope and less precision. [ABSTRACT FROM AUTHOR]

Illegal drugs are becoming a public health problem in African cities. In 2021, Bombé, a new drug of unknown composition, caused an outbreak of neuro-psychiatric symptoms in Kinshasa. Bombé was rumored to be based on ground catalytic exhausts stolen from cars. The chemical composition of six samples of Bombé obtained from different neighborhoods in Kinshasa was determined by triple quad liquid chromatography-mass spectrometry/mass spectrometry with confirmation by quadrupole time-of-flight mass spectrometry. Metals were determined by inductively coupled plasma-mass spectrometry, and polycyclic aromatic hydrocarbons were measured by gas chromatography-mass spectrometry. Analysis of the Bombé samples revealed that it contained heroin (2–12% of the total area under the curve of the samples) and opioid derivatives, plus paracetamol (33–72%), caffeine (17–26%), and also benzodiazepines (5/6 samples) and cyproheptadine (2/6 samples). The concentrations of neurotoxic metals were unremarkable. The median (range) concentrations of manganese and lead were 9.4 µg/g (range 3–334 μg/g) and 0.36 µg/g (range 0.1–3.12 μg/g), respectively. All polycyclic aromatic hydrocarbons were below the level of detection (<0.10 µg/g). Thanks to international collaboration, Bombé was documented to be a heroin-based drug and its alleged origin from catalytic exhausts was not substantiated. The local human expertise and technical capacity for undertaking toxicological analyses should be increased in Africa. [ABSTRACT FROM AUTHOR]

Food waste is a potential resource to prepare microbial fertilizer. However, functional microorganisms derived from the food waste compost (FWC) are relatively lacking. We have isolated, identified, characterized and optimized a high-yielding indole-3-acetic acid (IAA) strain from FWC and further evaluated its growth promoting effect on plants. A IAA high-yielding strain, Providencia sp.Y, with an initial IAA yield of 139.98 mg L−1, was obtained through high-throughput screening, and identified by 16S rRNA gene sequence. The novel strain Y may simultaneously involve the following three pathways from L-tryptophan to IAA, which were identified using liquid chromatography–tandem mass spectrometry: (1) L-tryptophan—indole-3-ethanol—indole-3-acetaldehyde—indole-3-acetic acid; (2) L-tryptophan—1-hydroxy-indole-3-ethanol—indole-3-acetic acid; (3) L-tryptophan—indole-3-acetamide—indole-3-acetic acid. The most suitable comprehensive conditions for IAA production, which were optimized by single factor experiment, were: culture time 12 h, inoculation amount 2% (v/v), NaCl concentration 4% (w/v), culture temperature 25℃, initial pH = 5, and L-tryptophan concentration 3.0 g L−1. The yield of IAA after optimization was increased by 590.48%, from 139.98 mg L−1 (before optimization) to 966.54 mg L−1. Diluted 200-fold microbial suspension could significantly improve the growth of pakchoi seedlings. The seedling plant height, root length, leaf width, leaf length, and fresh weight with microbial suspension increased by 17.39%, 107.35%, 77.98%, 37.75%, and 215.38%, respectively, compared with those without microbial suspension. The increase was greater than that of commercial bacterial agents. In conclusion, this isolated strain can be used as an economical microbial inoculant and provides a new germplasm resource for developing microbial fertilizers. [ABSTRACT FROM AUTHOR]

Background: Changes in cortisol binding globulin (CBG) impact the total serum cortisol concentration and affect the accurate assessment of adrenal function. Free biologically cortisol can be calculated using different equations or directly measured after complicated procedures. Methods: The free cortisol index (FCI) obtained using the Bonte formula as well as the free cortisol concentration calculated (Coolens equation) were first estimated for 45 healthy workers. The CBG level was determined by a competitive radioimmunoassay and the total cortisol concentration, was measured with an electrochemiluminescent assay. The correlations between FCI, the free cortisol concentrations calculated and the free cortisol levels measured with liquid chromatography-tandem mass spectrometry after equilibrium dialysis were studied for those 45 samples. Reference limits were established on 158 healthy hospital workers and patients with serum samples collected between 7:30 am and 10 am. Results: The FCI as well as the free cortisol concentrations calculated obtained for the 45 samples correlated significantly with the free cortisol levels measured. Although the cortisol and CBG levels were statistically higher in women using contraceptives compared with women not taking them as well as men, the calculated FCI and free cortisol concentrations did not differ between these groups. The medians (P2.5-P97.5) obtained for the 158 healthy workers were respectively 26.4% (12.3-51.6%) and 10.6 nmol/L (4.3-26.7 nmol/L). Conclusions: This study highlighted a significant correlation between the FCI, the free cortisol concentrations calculated and the free cortisol levels measured with LC-MS/MS, it has also allowed the establishment of reference intervals for calculated FCI and free cortisol. [ABSTRACT FROM AUTHOR]

Bamboo and wood are widely used as food contact materials (FCMs). Fungicides are often applied during the manufacture of these products to prevent mildew; thus, monitoring for fungicide residues is essential because of the possible risks to food safety. However, it is not clear whether residual fungicides in treated bamboo and wood products migrate into food to cause harm to humans, and there is an absence of procedures for these analyses. In this study, the simultaneous determination of fungicides was validated in bamboo and wood FCMs by high-performance liquid chromatography–triple quadrupole tandem mass spectrometry (HPLC–MS/MS). The analytes were extracted with methanol or 1:1 methanol/acetonitrile and purified using 25 mg primary secondary amine adsorbent with 2.5 mg graphitized carbon black or 25 mg PSA with 25 mg octadecylsilane (C18). The recoveries for wood and bamboo FCMs were from 60.0% to 100.7% and 70.0% to 97.5%, respectively. The intra-day precision of wood and bamboo FCMs were from 0.1% to 5.3% and 0.1 to 3.0%, and the inter-day precision from 0.3% to 8.5% and 1.2% to 7.8%, respectively. The limits of detection ranged from 0.11 to 15.38 for wood and 0.25–6.19 μg kg−1 for bamboo. This method provides a reference for the determination of fungicides in bamboo and wood FCMs. [ABSTRACT FROM AUTHOR]

Although restricting environmental quality values for organotin compounds (OTs) are set by Directive 2013/39/EU of the European Parliament, marine environment remains being affected due to maritime circulation at global scale. Fish and seafood accumulate OTs, making fish and seafood consumption the main source of OTs in humans. Because of the fish and seafood matrices complexity and the required low limits of detection, a robust and fast procedure for the quantification of OTs in fish and seafood, using ultrasound-assisted extraction and gas chromatography–tandem mass spectrometry, was validated and applied. Detection (2.7 µg Sn kg−1) and quantification (8.0 µg Sn kg−1) limits, repeatability and intermediate precision (<10%), accuracy by analysing ERM®-CE477 Mussel Tissue and analytical recoveries (65–122%) were assessed. Multivariate analysis shown that the matrix effect for some OTs displayed good negative correlation with the fat and protein content. Health risk assessment of OTs intake revealed no serious risk for human consumption. [ABSTRACT FROM AUTHOR]

A paper spray tandem mass spectrometric (PS-MS/MS) method without column separation was developed for the rapid screening of clonidine in dietary supplements. PS-MS/MS provided acceptable performance compared to high-performance liquid chromatography – tandem mass spectrometry (HPLC-MS/MS) in terms of limits of detection and quantification, accuracy, and precision. To overcome ionization suppression of complicated plant-based pharmaceutical products, nizatidine, tizanidine, and apraclonidine were investigated as internal standards. A more similar structured internal standard is most suitable for matrix effect compensation. The developed method has advantages of simplicity and speed for the screening of clonidine in dietary supplements. [ABSTRACT FROM AUTHOR]

In this study, 135 samples of cocoa beans collected in the Amazon and Atlantic Forest regions of Brazil were analysed to evaluate the possible co-occurrence of 34 mycotoxins. The results indicate that 42% of the cocoa samples exhibited quantifiable levels for 11 mycotoxins: aflatoxins (AFs) B1, B2 and G1; ochratoxin A; citrinin; cyclopiazonic acid; tenuazonic acid; paxilline; sterigmatocystin; zearalenone and fumonisin B2. Of the samples, 18% exhibited the co-occurrence of up to six mycotoxins. No toxins belonging to the groups of trichothecenes or ergot alkaloids were detected. Contingency analysis of the incidence of mycotoxins did not show significant differences between the two regions evaluated. Seven samples were contaminated with AFs, while only one contained ochratoxin A above 10 μg kg−1. The accuracy of the method was evaluated by proficiency testing for ochratoxin A, where satisfactory Z-scores were obtained. [ABSTRACT FROM AUTHOR]

A sensitive extraction and instrumental method was established to detect topramezone and its metabolite (M670H05) in maize and animal-origin foods. Two years of field experiments were carried out to study the dissipation dynamics of topramezone in maize straw, and their residue levels of actual samples collected from the supermarket were determined. They were extracted using liquid–liquid extraction (LLE), and ultra-high-performance liquid chromatography–tandem mass spectrometry was used for detection. The limit of quantification was 0.005 mg kg−1. Recoveries ranged between 73.8% and 109.9% at 3 spiking levels with intraday relative standard deviation (RSD) ≤17.7% and the inter-day ≤18.1%, which meets the requirements of SANTE/12682/2019. Dissipation dynamics experiment showed that, the deposition of topramezone in maize straw in Jilin were <0.005–0.62 mg kg−1with 28 days after application. And the residue level of market samples were all less than 0.005 mg kg−1, much lower than the MRLs (range from 0.01 to 0.8 mg kg−1) set by European Union, United States Food and Drug Administration, China, and Canada. This method was effective to analyse the residues of topramezone and M670H05. [ABSTRACT FROM AUTHOR]

Curry leaf is an evergreen herb with culinary, pharmaceutical, and nutraceutical applications. As pesticide residue in curry leaf has garnered significant regulatory attention in recent years, here we report a reliable method, which was validated for the determination of 265 and 225 pesticides using LC-MS/MS and GC-MS/MS, respectively. At first, the sample was comminuted after adding water (1:2). The sample preparation workflow included extraction of 10 g homogenized sample with 10 mL ethyl acetate (+1% acetic acid), cleanup by dispersive solid phase extraction (d-SPE, 50 mg PSA + 50 mg C18 + 10 mg GCB + 150 mg Na2SO4) and the final analysis by tandem mass spectrometry. The cleanup step adeptly removed co-extractives. The method effectively reduced matrix effects and offered an LOQ of 0.01 mg kg−1 for most compounds. The method's accuracy and precision results fulfilled the requirements of SANTE/11312/2021 guidelines at 0.01 mg kg−1 and higher levels of fortification. The accuracy and precision results were comparable for all pesticides. The successful screening of market samples indicates its high extraction efficiency and precision for incurred residue analysis. Due to its robustness and conformity with regulatory criteria, food testing laboratories worldwide can use the method to monitor pesticide levels in curry leaves. [ABSTRACT FROM AUTHOR]

Molnupiravir a novel oral broad-spectrum antiviral drug initially developed for the treatment of COVID-19, was quantified using UV spectrophotometric and high-performance liquid chromatographic methods. The linear regression analysis used to build the equations for the multivariate calibration method used the correlation between absorbance and concentration at a set of five different wavelengths. The suggested method can separate Molnupiravir and its breakdown products using a C18 column containing ethanol and phosphate buffer (42.5:57.5% v/v), a flow rate fixed at 0.9 mL/min, and detection done at 235 nm. The suggested techniques were examined and approved in accordance with ICH Q2 (R1) standards. For the UV and HPLC methods, the linearity ranges for molnupiravir were 4-9 and 10-150 g/ml, accuracy, repeatability, and selectivity, with R2 values were 0.9999 and 0.9999 with recoveries between 98 and 102% and 2% RSD. The unique strategy was additionally assessed utilising three ways, including additional assessment techniques, such as GAPI, AES, and AGREE, and it was discovered to be environmentally friendly. Based on our findings, developing new pharmaceutical drugs may benefit from using UV and HPLC procedures with Green Analytical Performances using the Quality by Design methodology to assess drug stability. [ABSTRACT FROM AUTHOR]

A method is reported for the simultaneous determination of ceftazidime and avibactam in human plasma and cerebrospinal fluid utilizing high-performance liquid chromatography – tandem mass spectrometry (HPLC-MS/MS). The validated method was used to monitor the drugs in the treatment of central nervous system infections. The analytes were extracted from plasma and cerebrospinal fluid by simple protein precipitation using acetonitrile. A reversed-phase HSS T3 column (5.0 μm, 4.6 × 100 mm, Waters) was employed for the separation with a total analysis time of 5 minutes. Ceftazidime and avibactam eluted in 2.15 min and 2.87 min, respectively. The acquisition was separated into two periods to allow analysis in different ionization modes. A multi-reaction monitoring analysis was performed with the transition m/z 547.2–468.1 for ceftazidime, and m/z 552.3–468.1 for ceftazidime-d5 (positive mode), m/z 263.9–96.1 for avibactam, and m/z 136.8–92.8 for salicylic acid (negative mode). The plasma calibration curves of the analytes displayed good linearity across the range from 1 to 100 μg/mL for ceftazidime and 0.1–20 μg/mL for avibactam. Calibration curves for cerebrospinal fluid assay were established from 0.4 to 16 μg/mL (ceftazidime) and 0.2–8 μg/mL (avibactam). The accuracy was between 89.5% and 108.5%. The within- and between-batch precisions with the relative standard deviation were lower than 15%. The developed method had no observed matrix effects. The analytes were stable during the analytical and sample processing. The developed and validated method was successfully applied in routine clinical practice and helps to assess the adequacy of therapy and ensure sufficient ceftazidime and avibactam levels in central nervous system infections. [ABSTRACT FROM AUTHOR]

Plastic recycling is necessary to reduce pollution. However, the impurities in recycled plastics restrict their applications. Potential contaminants in recycled plastics were investigated by untargeted and targeted liquid chromatography-mass spectrometry (LC-MS). More than 2000 features were screened by comparing the recycled plastics with food contact polyolefin materials. A total of 126 substances was identified using the mzCloud database. In order to assess the risk of recycled plastics, Cramer rules were applied to predict the safety levels of the identified compounds. 23 identified Cramer class III compounds were assigned, including plasticizers, antioxidants, and flame retardants. Six more commonly identified toxic compounds were further characterized by standards using tandem mass spectrometry. These results suggested that the identification of contaminants in recycled plastics by LC-MS and mzCloud match was reliable. Additionally, their concentrations were determined by LC-MS to estimate the potential risk of recycled plastics. The results show that the organic additives in recycled plastics and food contact polyolefins are significantly different. Recycled plastics may present a safety risk and should be assessed before use in some applications. [ABSTRACT FROM AUTHOR]

Liquid chromatography – tandem mass spectrometry (LC-MS/MS) is routinely applied for the determination of toxins associated with diarrhetic shellfish poisoning (DSP) as a part of the Japanese official method. For scallops, not only the edible part but also the midgut gland may be used for analysis. In this study, the matrix effects in the LC-MS/MS-based determination of okadaic acid (OA) and dinophysistoxin-1 (DTX1) in the scallop midgut gland were evaluated to assess the impact on the accuracy of the results. The analyzed sample in an interlaboratory comparison study was subjected to the Japanese official method. The solutions obtained with and without a cleanup process (combination of hexane washing and solid-phase extraction using a C18 cartridge) were diluted to varying ratios and used for evaluation. For all prepared solutions, the ionization of OA and DTX1 was enhanced compared to the samples in methanol; the cleanup process did not sufficiently reduce the matrix effects. Although the dilution of the sample solution reduced the matrix effect, the improvement was limited. Another pretreatment technique is necessary for the accurate determination of DSP-associated toxins in this matrix. [ABSTRACT FROM AUTHOR]

The paper reports a multiresidue method that was validated on 220 multi-class pesticides in three major Indian soils, namely, (i) new alluvial soil (NAS); (ii) red lateritic soil (RS) and (iii) black soil (BS) from three different regions. An ethyl acetate-based extraction method with a freezing-out cleanup step was employed for sample preparation, followed by gas chromatography-tandem mass spectrometric analysis. The method that was initially optimized on BS worked satisfactorily for the other two soil matrices. At the spiking level of 10 µg/kg (LOQ), the recoveries were satisfactory (within 70–120%) with precision-RSDs, ≤20% (n = 6) for 85, 88.6, and 89% of compounds in BS, RS, and NAS respectively. At 20 µg/kg, the method performance was satisfactory in each soil for all pesticides. When this validated method was applied to analyse 25 field samples, 6 pesticides were detected in them. In each case, precision (RSD) was <20%. The method sensitivity, accuracy and precision complied with the SANTE/2020/12830 guidelines. The method can be applied for environmental monitoring and risk assessment purposes, thus aiding in regulating pesticide usage in agricultural fields. The limitations and future scope of the study are also discussed. A multiresidue method is reported for simultaneous analysis of multi-class pesticides in diverse soils The method was validated on 220 pesticides in new alluvial, red lateritic and black soils Sample preparation involved extraction with ethyl acetate and cleanup by a freezing step The residues were estimated by gas chromatography tandem mass spectrometry (GC-MS/MS) The method accuracy and precision complied with the EU's SANTE guidelines [ABSTRACT FROM AUTHOR]

Alpha-methylthiofentanyl and thiofentanyl are psychoactive substances that have been abused in recent years, strongly threatening social and public security. Because they are rapidly metabolized in vivo, their determination presents a great challenge for forensic science. An automated method of online solid-phase extraction coupled with ultra-high performance liquid chromatography—tandem mass spectrometry was developed for the determination of alpha-methylthiofentanyl, thiofentanyl, and the metabolite norfentanyl in urine. The analytes were first enriched and purified by an Oasis HLB online SPE column and eluted on a Hypersil GOLD C18 analytical column. Chromatographic separation was achieved with mobile phase components of 2 mM ammonium formate and 0.1% formic acid in water and same composition in methanol in gradient elution mode. The limit of detection and lower limit of quantitation of the method for the three analytes were 0.2 and 2 pg/ml, respectively. Acceptable linearity was obtained from 2 to 800 pg/ml. The accuracy was in the range of 87.98–108.95%; and precision, calculated as the relative standard deviation, was less than 14.63%. The method recoveries were from 65.56 to 113.72%. This highly sensitive method was applied to study the detection window of the precursor compounds and metabolites in rat urine. Both alpha-methylthiofentanyl and thiofentanyl are metabolized to norfentanyl, which was first revealed in this study. With the aid of norfentanyl, the detection windows of alpha-methylthiofentanyl and thiofentanyl were extended to 18–26 days and 20–27 days, respectively. This study provides important auxiliary tools for the forensic identification of fentanyl analogs. [ABSTRACT FROM AUTHOR]

Immunohistochemistry showed that systemic amyloid deposits were positive for ApoAIV (Figure 1(c, f, i)) and negative for serum amyloid A, light chain, light chain, and transthyretin. Apolipoprotein A-IV (ApoAIV) amyloidosis is a rare type of systemic amyloidosis characterised by ApoAIV-derived amyloid deposits in the kidney and heart [[1]]. Except for ApoAIV, the immunoglobulin lambda light chain was detected as a protein having amyloidogenic properties but significantly and distinctly lower level than those of ApoAIV, which indicates that ApoAIV detected in this case, was not an amyloid signature protein but amyloid precursor protein. [Extracted from the article]

Background The Academy of Breastfeeding Medicine published a clinical protocol for Human Milk storage, recommending refrigeration at a temperature of 4 °C up to 4 d as the optimal conditions for the safety and bactericidal capacity of Human Milk. However, few studies were conducted to evaluate the change in milk composition during this type of refrigeration storage. Aim To elucidate some uncertainties regarding the Human Milk composition and prolonged cold storage, we have investigated the effects of storage at 4 °C up to 96 h on an important category of oxidative stress markers: the Isoprostanes (F2-isoprostanes, F4-neuroprostanes and F3-isoprostanes). Material and method The experiment was repeated 3 times to ensure reproducibility of the results. We enrolled 3 donating healthy mothers for each time (total: 9 mothers). Milk was collected with standard extraction methods. Immediately after collection, each Human Milk sample from each mother was pooled and then divided into 5 aliquots. One aliquot (0 h) was immediately frozen at −80 °C until the analysis. The other aliquots (24 h, 48 h, 72 h, 96 h) were stored in a refrigerator at 4 °C respectively for 24, 48, 72 and 96 h, then immediately frozen at −80 °C until the analysis. Milk samples were then used to determine concentration of Isoprostanes in Liquid Chromatography - Mass Spectrometry and Liquid Chromatography - Tandem Mass Spectrometry. Results Isoprostanes were detectable in all Human Milk samples. There was no significant trend of the concentration of the tested analytes over time. Discussion and conclusion This study provides evidence of the presence in human milk of all the tested isoprostanes: in particular, F2-isoprostanes, F4-neuroprostanes and F3-isoprostanes. Refrigeration and storage of fresh Human Milk in controlled conditions for 96 h did not significantly affect its bioactivity and nutritional quality related with these biomarkers. [ABSTRACT FROM AUTHOR]

The concern for human exposure to bisphenol A (BPA) has led to the introduction of other bisphenols to be used as substitutes in industrial processes. These compounds show activity similar to BPA as endocrine disruptors and could be already widespread both in the environment and in food. To monitor their possible occurrence in the food chain, an analytical method based on affinity chromatography clean-up and UHPLC coupled to tandem mass spectrometry detection was developed and in-house validated according to European law, for simultaneous determination of 17 bisphenols in milk and blood serum from bovine and buffalo, in drinking water and in feed. The analytical performance parameters of the method for these matrices were determined. The results showed satisfactory precision in terms of relative standard deviation (3.3%–21.4%), overall good trueness as mean percentage recoveries (77.0%–119.4%), with the only exception of bisphenol PH and bisphenol S in milk and BPA diglycidyl ether in serum. The high specificity and sensitivity of the method allowed us to determine the analytes at very low concentrations, that is, 0.01–1.0 ng/mL in water, 0.1–2.0 ng/mL in milk, 0.01–1.0 ng/g in blood serum and 1.0–10.0 ng/g in feed. [ABSTRACT FROM AUTHOR]

Tramadol-attributed toxicity may involve opioid-like, serotoninergic, and noradrenergic mechanisms. We investigated the mechanisms of toxicity in a massive tramadol ingestion case by examining serial clinical, imaging, electroencephalography, pharmacokinetics, and genotyping data. A 32-year-old female who presumably ingested 9000 mg sustained-release tramadol was found comatose without hypoglycemia, bradypnea, hypotension, marked hypoxemia or seizures. She developed eyelid myoclonus and non-reactive mydriasis. Electroencephalogram showed non-reactive encephalopathy. MRI showed extensive brain injury. Despite supportive care and ventricular derivation, brain death occurred on day 12. Plasma concentrations of tramadol and metabolites were measured using a liquid chromatography–tandem mass spectrometry assay. Genotyping for the presence of metabolizing cytochrome P450 (CYP) gene polymorphisms was performed. Plasma concentrations of tramadol and metabolites were extremely high (∼70-fold the therapeutic concentrations) and slowly decreased during the first ∼146 h post-admission, possibly due to prolonged gastrointestinal absorption. Elimination half-lives were 2–3-fold longer than usual values. The patient was an intermediate CYP2D6 metabolizer with decreased CYP3A4 and CYP2B6 activities. Clinical and electroencephalographic data did not support the hypotheses of opioid or serotoninergic toxicity nor prolonged/repeated seizures. Based on serial imaging showing progressive extension of ischemic edema in the context of prolonged high plasma concentrations, we hypothesized a cerebral vasospasm as mechanism of injury. Massive tramadol ingestion with prolonged high plasma concentrations can result in severe brain injury, possibly involving vasospasm. [ABSTRACT FROM AUTHOR]

Heterocyclic aromatic amines (HAAs) are carcinogenic and mutagenic compounds formed by the cooking of meat and combustion of biomass. There are relatively few data on HAAs in atmospheric particulate matter (PM). We developed an analytical method using high performance liquid chromatography – tandem mass spectrometry (tandem quadrupole, HPLC-MS/MS(QqQ)) to analyze PM samples for 12 HAAs. We applied this method to an urban air standard reference material and wildfire-impacted PM2.5 from the 2018 wildfire season in Northern California. The PM sample matrix adversely impacted the MS/MS response, with high levels of ion suppression for sample masses >4 mg and higher ion suppression in wildfire-impacted particulate matter compared with the standard reference material. Despite detection limits at the low ng level, no HAAs were detected in the standard reference material, but β-carboline norharman (0.34 ng/m3) was detected in one wildfire sample. [ABSTRACT FROM AUTHOR]

Per- and poly-fluoroalkyl substances (PFASs) are a class of synthetic organic chemicals that include thousands of compounds. Analytical methods for PFASs in vegetables are limited. In this study, a rapid and sensitive method using on-line solid phase extraction (SPE) coupled with ultra-high performance liquid chromatography-tandem mass spectrometry (UHPLC-MS/MS) was developed and validated for the simultaneous determination of 21 PFASs in vegetables. The extraction solvent volume and procedure were optimized to achieve good efficiencies (>93%) using the lowest quantity of solvent. The injection volume, elution condition of the online SPE system, and the mobile phases of the UHPLC-MS/MS system were also optimized to improve the sensitivity, peak symmetry, and resolution. The method detection limits of the 21 targeted PFAS were from 0.001 to 0.008 ng/g and the linearity was from 0.1 to 1000 pg/mL using an injection volume of 5 mL. The validation results indicate that this method is precise, accurate, and robust. Moreover, this method is high throughput (∼15 min per sample); thus, suitable for analyzing a large number of vegetable samples in a short time interval. In addition, the developed method was successfully applied to analyze vegetables. The results show that the total PFAS concentrations were the highest in lettuce, followed by potatoes and tomatoes, and the lowest in broccoli. Different profiles of PFASs were observed among the vegetable species. [ABSTRACT FROM AUTHOR]

Food additives are used in numerous food products and are characterised by various physicochemical properties. In European member states, their use in food is regulated by the European Union. This work aimed to develop an accurate and high-throughput analytical method enabling the simultaneous determination of additives from different functional classes to facilitate controls and generate occurrence data for exposure assessments. The QuEChERS principle was applied due to its ease of implementation and flexibility to adjust to various food matrices. However, very polar substances could not be extracted with sufficient recoveries. Consequently, an alternative basic methanol sample-preparation methodology was developed. After sample preparation, the obtained extracts were analysed using ultra-high-performance liquid chromatography coupled to tandem mass spectrometry (UHPLC-MS/MS). Overall, the developed methodology allowed the quantification of 27 additives from the functional classes of colours, sweeteners, preservatives, and antioxidants in various foods (e.g. beverages, dairies, processed meals). The methods were also validated in terms of selectivity, linearity, matrix effect, limit of quantification, accuracy, repeatability, and intra-laboratory reproducibility. Finally, the methods were successfully applied to eighty-four actual samples. All additives were found below authorised levels. However, irregularities were spotted in labelling. [ABSTRACT FROM AUTHOR]

The bio-analytical method was developed and validated for simultaneous detection and quantification of paclitaxel (PAC) and erlotinib (ERL) in plasma samples. The sample preparation process was accomplished by liquid-liquid extraction technique. The dried and reconstituted samples were subjected to chromatography on Discovery -C18 (50 × 4.6 × 5µm) column and a mobile phase, composed of a mixture of 0.1% formic acid in water: acetonitrile (70:30, v/v), in isocratic mode at a flow rate of 0.6 mL/min. Liquid chromatography coupled to tandem mass spectrometry detection in positive ion mode was selected to provide optimal selectivity and sensitivity. The mass transitions of erlotinib, erlotinib13C6, Paclitaxel and docetaxel were m/z 394.5→278.4, m/z 400.4→284.5, m/z 876.6→308.4 and m/z 830.0→304.0 respectively. The linearity in the calibration curves was obtained in the concentration range of 3.6 − 1006.7 ng/ml (r ≥ 0.99) for erlotinib and 5.3 − 1500.0 ng/mL for paclitaxel with an LLOQ (lower limit of quantification) of 3.6 and 5.3 ng/ml respectively. The run time was achieved in 2.5 min only, for all the analytes. [ABSTRACT FROM AUTHOR]

The indiscriminate use of organophosphorus pesticides poses a great threat to human health because of harmful substance bioaccumulation. We developed a rapid and reliable method for the simultaneous determination of chlorpyrifos, isocarbophos, methamidophos, omethoate, and triazophos in procine hair. The targets were separated by a C18 column (2.1 × 100 mm, 1.8 µm) and analyzed by electrospray ionization using the positive mode of a triple quadrupole mass spectrometer. The analytes had linear relationships from 1.0 to 100 µg/kg. The correlation coefficients were all greater than 0.998. The limits of detection ranged from 0.4 to 0.9 µg/kg, and the limits of quantification from 1.2 to 2.0 µg/kg. The recoveries were from 76.1% to 106.2%. The intra-assay and inter-assay precision rates were from 1.6% to 4.4% and 2.3% to 6.9%, respectively. The intra-day and inter-day accuracy ranged from 2.5% to 9.3% and 3.2% to 8.9%, respectively. This method was a valid tool to monitor organophosphorus pesticides in breeding and livestock products. [ABSTRACT FROM AUTHOR]

The aim of this study was to determine the presence of zoocide (insecticide and miticide) residues in hops collected in three hop-growing regions located in the Czech Republic, and to assess their zoocide profiles and residue levels in terms of variability in temperature and precipitation across the 2018–2020 seasons. Furthermore, the weather factors that influenced the occurrence of hop pests are described and discussed. During our 3-year survey, a total of 120 samples of whole-cone hops samples harvested in three hop-growing regions were analysed for the presence of 29 insecticides and miticides using the modified QuEChERS extraction method, followed by liquid chromatography-tandem mass spectrometry and gas chromatography-tandem mass spectrometry. A majority, 119 of 120 samples, contained a residue of at least one of the active substances surveyed in this study, and 34 analysed samples contained multiple residues with three to four zoocides presented. Concerning the most frequently detected zoocide residues, spirotetramat and/or its metabolites were found in 94.2% of the samples at levels ranging from 0.02 to 1.08 mg/kg. Of the other zoocides surveyed, residues of fenpyroximate, hexythiazox, bifenazate and lambda-cyhalothrin were routinely found in hop cone samples. Obtained data were then used for evaluating seasonal and geographical variations in the profile of zoocide residues among the hop-growing regions in the years 2018–2020, and the compliance with legal regulations concerning the use of zoocides on hops was ascertained. The results showed that (1) the profile and levels of zoocide residues found in the samples reflected seasonal prevalence of pest infestation on hop plants; (2) the strategy to control pests (especially aphids) used in most of hop yards was consistent across the seasons; and (3) a concentration of spirotetramat residues less than 1 mg/kg was typical for hops grown in the Czech Republic. [ABSTRACT FROM AUTHOR]

Garcinia cambogia extract (GCE) is a popular botanical supplement used in weight loss products. Hydroxycitric acid (HCA) is the principal component in GCE. Due to lack of adequate toxicity data to assess the safe use of GCE, the National Toxicology Program is testing GCE in Hsd:Sprague Dawley SD rats following perinatal exposure and in adult B6C3F1/N mice. We report a validated method utilizing sample clean up with ultrafiltration followed by liquid chromatography—tandem mass spectrometry (LC-MS/MS) analysis to quantify HCA in rat plasma across the concentration range from 20 to 800 ng/mL. The method was linear (r2 ≥ 0.99) with limits of quantitation (LOQ) and detection (LOD) equal to 20.0 and 3.9 ng/mL plasma, respectively. The accuracy (determined as the relative error, RE) and precision (determined as the relative standard deviation, RSD) using quality control standards analyzed over multiple days were ≤ ± 7.5% and ≤9.5%, respectively. The method was applied to quantify HCA in study matrices (relative error ≤ ± 23.0%; relative standard deviation ≤ 6.0) except gestational day (GD)18 fetus. The method was partially validated in GD18 fetal homogenate across the concentration range from 60 to 3000 ng/g (r2 ≥ 0.99, relative error ≤ ± 11.9%, and relative standard deviation ≤ 5.5%; LOQ 60.0 ng/g; LOD 7.77 ng/g). Standards as high as 20,000 ng/mL (plasma) and 502,000 ng/g (fetus) were successfully quantified after dilution into the validated range (relative error ≤ ± 2.6%; relative standard deviation ≤ 5.2%). These results demonstrate that the method is suitable to quantify HCA in rodent matrices and may be adapted to other biological matrices. [ABSTRACT FROM AUTHOR]

A fast, straightforward, efficient, and high throughput reverse-phase high-performance liquid chromatography and electrospray ionization mass spectrometry method has been developed to analyze tea extracts containing polyphenols. The polyphenols detected in green tea (GT), black tea (BT), and paradise tropical tea (PTT) were separated in 18 min at wavelengths 254 nm, 260 nm, and 280 nm with a gradient elution on the RP-HPLC system. Our approach detected, identified, and quantified three catechins in the tea extracts analyzed, and the response at 280 nm wavelength was the best. The ESI-MS data confirmed the fragmentation patterns of the catechins detected in the tea extract. The validation data showed that the limit of detection (LOD) and limit of quantitation (LOQ) of catechins ranged from 5.26 ± 0.02 to 36.44 ± 0.02 ppb, and 17.52 ± 0.03 to 121.45 ± 0.16 ppb, respectively, for six catechins studied. The standard addition calibration approach used to quantify the catechin content in the tea extract simultaneously showed that PTT has a higher catechin content than GT and BT. The content of polyphenols in GT, BT, and PTT are summarized. This approach holds great promise for quality control studies to quantify polyphenols in nutritional products. [ABSTRACT FROM AUTHOR]

Osteoporosis is a worldwide disease that seriously affects the quality of life and survival rate of the elderly. The detection of bone biomarkers will provide on bone mineral density, contributing to the accurate diagnosis of osteoporosis and better health care for prevention. This study aimed to investigate the efficacy of oxidative stress markers—8-oxo-7,8-dihydroguanine (8-oxoGsn) and 8-oxo-7,8-dihydro-2′-deoxyguanosine (8-oxodGsn) in the assessment of osteoporosis. We conducted a cross-sectional study among menopausal women with a mean (standard deviation) age of 62.967 (7.798) years old (n = 151). Participants were recruited for the bone mineral density (BMD) assessment, blood and urinary samples. Urinary 8-oxo-7,8-dihydro-2′-deoxyguanosine and 8-oxo-7,8-dihydro-guanine concentrations were measured by ultra-performance liquid chromatography and tandem mass spectrometry (UPLC-MS/MS). The urinary 8-oxoGsn/Cre value differed significantly between normal and osteoporotic participants (p < 0.001), while the 8-oxodGsn/Cre value did not (p = 0.720). Even after adjusting for the age and body mass index, the BMD was still associated with urinary 8-oxoGsn/Cre value. ROC analysis showed that 8-oxoGsn has a strong diagnostic value for osteoporosis (AUC = 0.744). The results show for the first time that 8-oxoGsn may be a biomarker for the future diagnosis of osteoporosis in women. [ABSTRACT FROM AUTHOR]

Natural-derived steroids and their analogues are present in various plants and insects. To minimize the chance of missing a positive doping test and avoiding potentially serious health problems, adequate screening methods are necessary for the detection of a wide range of natural-derived steroids and their analogues in dietary supplements. In this study, an accurate and simple liquid-chromatography-tandem mass spectrometry (LC-MS/MS) method was developed and validated to determine and quantify the natural-derived steroids and their analogues according to the International Conference on Harmonization of technical Requirements for Registration of Pharmaceuticals for Human Use guidelines. The validation results indicating excellent extraction efficiency and low matrix effects show that the LC-MS/MS method is reliable for the detection of natural-derived steroids and their analogues. In addition, we established the ion fragmentation of turkesterone and ion fragmentation of four natural-derived steroids and their analogues. The validated method was applied to 60 dietary supplements purchased online and in person from international vendors in 2020. Ecdysterone and 5α-hydroxylaxogenin were detected respectively in 3 and 14 of 60 dietary supplements. Especially, a high amount of 5α-hydroxylaxogenin, an FDA-unapproved ingredient, was detected in two of dietary supplements (44.4 and 32.3 mg/g). This component should be controlled since it may cause unexpected side effects if administered excessively. Thus, this method will be helpful for the continuous control and supervision of unlicensed dietary supplements containing natural-derived steroids and their analogues. [ABSTRACT FROM AUTHOR]

The goal of the current work was to study the phytochemical content of Onosma inexspectata Teppner and O. armenum DC. The antioxidant properties using six assays and the enzyme inhibitory capacities against α-amylase, α-glucosidase, tyrosinase, and the anti-cholinesterase were also evaluated. The levels of phenolic compounds were approximately 22 and 28 mg gallic acid equivalent/g for O. inexspectata and O. armenum, respectively. Twenty-seven compounds were identified and quantified using liquid chromatography–electrospray ionization tandem mass spectrometry. Chlorogenic acid, apigenin 7-glucoside, and luteolin 7-glucoside were the major compounds in O. inexspectata. Onosma armenum contained an attractive level of hesperidin. The antioxidant assays showed significant differences between the two species, except for the phosphomolybdenum assay. The results of the inhibitory enzyme assays revealed no significant differences between the extracts, except for α-glucosidase inhibition. The present study may underline the possibility to use O. inexspectata and O. armenum as promising sources of phytochemicals that may serve against many body disorders. [ABSTRACT FROM AUTHOR]

In this study, we developed and validated a liquid chromatography triple quadrupole tandem mass spectrometry (LC-MS/MS) method used to simultaneously determine levels of four fluoroquinolones (ofloxacin, norfloxacin, lomefloxacin, and pefloxacin) and two antipsychotics (diazepam and methaqualone) in fish and shrimp. The samples were extracted with a mixture of anhydrous sodium sulfate and acetonitrile, and purified by C18 cartridge solid-phase extraction with an optimized eluent. The MS2 method was applied to recognize the molecular structure of these compounds according to a main fragmentation scheme. The key ions of identification and quantification were deduced from chemical structures. Multiple reaction monitoring was used to quantitatively analyse the compounds of interest. Satisfactory linearities were obtained (R2 ≥0.99) with the limits of quantitation (LOQs) ranging between 0.03 and 1.96 μg kg−1. The recoveries were 74–122%, with a relative standard deviation (RSD) below 4.9% for these compounds at the spiking level of three, five, and ten times the LODs, respectively. The LC-MS/MS method allows precise and sensitive determination of residues of six important banned veterinary drugs in fish and shrimp tissue. This methodological approach solved the problem imposed by the need for two or more analysis methods to analyse the compounds of interest described in this study. [ABSTRACT FROM AUTHOR]

Strawberries are widely cultivated and highly consumed globally, but pests and diseases can severely affect yields. Phenamacril and difenoconazole are high-efficacy pesticides and the mixture of these two pesticides offers a satisfactory option for disease control. In this study, an optimised QuEChERS method combined with dispersive solid-phase extraction purification before injection for simultaneously determining the residues of phenamacril–difenoconazole mixture on strawberries was developed and validated using ultra-performance liquid chromatography-tandem mass spectrometry (UPLC–MS/MS). Average recoveries of phenamacril and difenoconazole in the strawberry matrices ranged from 100% to 104% and 99% to 104%, with relative standard deviations of 2.6%–5.3% and 2.2%–5.5%, respectively. The degradation half-lives of phenamacril and difenoconazole were 3.5–6.6 days and 2.2–3.4 days on strawberries, respectively. Final residues of phenamacril and difenoconazole on strawberries at eight different cultivation regions were 0.033–0.66 mg kg−1 and <0.02–0.089 mg kg−1 after spraying at the maximum dosage recommended by the company of 300 mg a.i. kg−1 twice, respectively. Overall, this study is the first report of phenamacril and difenoconazole residue analysis in strawberries. Therefore, it could provide the reference data for safe management and proper use of phenamacril and difenoconazole in China. [ABSTRACT FROM AUTHOR]

A rapid and sensitive method was developed determine free fatty acids in cyanobacteria extracellular medium without derivatization by stir bar sorptive extraction (SBSE) coupled to ultra-high-performance liquid chromatography – tandem mass spectrometry (UHPLC-MS/MS). The stir bars (20 mm in length and 1 mm in film thickness) coated with polydimethylsiloxane was used to directly extract 11 free fatty acids (C14-C24) in cyanobacteria extracellular media. The performance was optimized, including the column, temperature, extraction time, organic modifier, and desorption solvent. Limits of detection and quantification, precision, and linear dynamic ranges for the free fatty acids were evaluated. The method was applied to determine free fatty acids in cyanobacteria extracellular media at the exponential and plateau phases. Eicosanoic acid (C20:0), linoleic acid (C18:2), oleic acid (C18:1), stearic acid (C18:0), palmitic acid (C16:0) and myristic acid (C14:0) were quantified in the samples. [ABSTRACT FROM AUTHOR]

A disposable pipette tip extraction (DPX) method followed by liquid chromatography coupled to tandem mass spectrometry (LC-MS/MS) was developed and validated to determine eleven herbicides employed in sugarcane crops. After improving conditions, the DPX method consists of conditioning a C18 tip with 0.3 mL of methanol, followed by the same volume of water and 0.15 mL of the sample. After completing the sorption interaction, the sample was dispensed, and elution was made with 0.15 mL of methanol before collecting the extract for injection. The total extraction time was 4 min, and recoveries ranged from 59.1 to 76.5%. DPX method was compared to cartridge solid-phase extraction, which presented recoveries between 30.4 and 108.6%. SPE consumed four times more solvent, total extraction time is five times longer than DPX, and cartridges are more expensive than the DPX tips. DPX performance was also evaluated by gas chromatography coupled with tandem mass spectrometry (GC-MS/MS). The recoveries were similar to LC-MS/MS. Furthermore, the DPX-C18-LC-MS/MS method was applied to analyze sugarcane-derived juice samples. Results indicate that the method can determine the herbicides in actual samples and other sugarcane matrices. [ABSTRACT FROM AUTHOR]

Poultry feathers are nowadays partially re-introduced into the animal food chain and the environment. They are valorised by their transformation into feather meal in order to be used as fertilisers in agriculture but also in animal feed (in particular, pet food and fish feed). However, unlike food producing animals for humans, feathers from poultry animals are not subject to a ban or regulatory limits on the presence of antibiotic residue after veterinary treatment. Feathers could therefore be a potential reservoir of antibiotic residues, unintentionally exposing the environment and animals through food, which might contribute to the emergence of antibiotic resistance. To this end, a multi-class liquid chromatographic method coupled with tandem mass spectrometry (LC-MS/MS) was developed for the detection and determination of residues of 30 antibiotics from eight groups of antibacterial (quinolones, lincosamides, macrolides, penicillins, phenicols, tetracyclines, sulphonamides and diaminopyrimidines) in feathers. The extraction of the analytes from the feathers was carried out by the salting out technique. The separation of the analytes employed a Kinetex C18 column. Quantification was made using internal standards. All analytes have been validated according to the performance criteria of Decision 2002/657/EC. Trueness of the method ranged from to 93% to 111% for all analytes and intermediate precision were to 1.2–18.8%. The limits of quantification (LOQ) were from 13 to 150 µg kg−1 depending on the analytes. The method is suitable for the monitoring and quantification of antibiotic residues in feathers over the range 13–600 µg kg−1 depending on the compound. [ABSTRACT FROM AUTHOR]

A sensitive, rapid and reproducible liquid chromatography-positive electrospray ionization- tandem mass spectrometry (LC-MS/MS) method was developed for the simultaneous quantification of Clomipramine and its active metabolite N-desmethyl Clomipramine in human plasma using Clomipramine-d3 and N-desmethyl Clomipramine d3 as an internal standard (IS). The analytes were extracted with solid phase extraction using cation exchange cartridges and analyzed on a BDS Hypersil C18 (100 mm × 4.6 mm, 5 μm) column. The mobile phase was composed of methanol: acetonitrile: 10 mM ammonium acetate (35:35:30 v/v/v). Clomipramine, N-desmethyl Clomipramine, Clomipramine d3 and N-desmethyl Clomipramine d3 detected in the multi-reaction monitoring (MRM) mode using LC-MS/MS (API 5500) productions of transitions as Q1→Q3 m/z 315.2→86.2, m/z 301.1→72.1, m/z 318.1→89.3 and m/z 304.2→75.2 respectively. The matrix effect, recovery, sensitivity, linearity, accuracy and precision were all evaluated over the concentration range of 0.500-200.000 ng/mL for both Clomipramine and N-desmethyl Clomipramine. In summary, the method was developed and validated successfully for intended to be use for the analysis of plasma samples of Bioavailability and Bioequivalence study of Clomipramine Tablets. [ABSTRACT FROM AUTHOR]

Parabens are widely used as antimicrobial preservatives in cosmetic products and pharmaceuticals. Therefore, their presence in the environment is considered to be serious and their determination is important. This paper reports the development and validation of a new method based on solid-phase microextraction (SPME) and high-performance liquid chromatography – tandem mass spectrometry (HPLC-MS/MS) for the simultaneous determination of five parabens (methylparaben (MP), ethylparaben (EP), propylparaben (PP), butylparaben (BP) and benzylparaben (BzP)) in surface water. The polymer sorbent was obtained by the electropolymerization of 3,4-ethylenedioxythiophene on a stainless steel spring support. The parameters affecting the extraction efficiency of parabens were optimized. Under optimal conditions, the extraction recoveries ranged from 88 to 98% except for BzP (70%). Good linear responses were obtained with correlation coefficients (r2) exceeding 0.999. The detection limits were from 0.004 to 0.28 µg L−1. The method was successfully applied for the determination of parabens in lake water. [ABSTRACT FROM AUTHOR]

Methods useful for the extraction of alkylphenols from soil samples were assessed. A comparison is made of the four extraction techniques that are most commonly used to extract phenolic compounds from soil, such as bisphenol A, bisphenol F and alkylphenols (4-t-OP, iso-NP, 4-OP and 4-n-NP). Soxhlet extraction, ultrasonic-assisted extraction (USE), accelerated solvent extraction (ASE) and the so-called Quick, Easy, Cheap, Effective, Rugged and Safe extraction (QuEChERS) were included. Modifications of the QuEChERS technique such as original, citrate and acetate were investigated. The effects of basic purification sorbents used for QuEChERS extracts such as a primary and secondary amine (PSA), C18 endcapped sorbents and graphitised carbon black (GCB) were tested. A derivatisation step prior to the final analyses by liquid chromatography coupled to a triple quadrupole analyser operating in tandem mass spectrometry (LC–MS/MS) was performed by using dansyl chloride (DNSC). The best extraction of the monitored compounds from spiked soil was obtained using QuEChERS extraction. Recoveries of phenolic compounds using the QuEChERS technique were in the range from 67% to 114%. The lowest extraction recoveries (16–73%) were obtained using ultrasonic extraction. The QuEChERS method was successfully applied for the analysis of alkylphenols in soil samples. Instrumental limits of quantification and limits of detection ranged from 0.08 to 0.83 pg per injection and 0.02 to 0.25 pg per injection, respectively. [ABSTRACT FROM AUTHOR]

Urea is authorised in the European Union (EU) as feed additive for ruminants. Because of its high molecular nitrogen content, it is a substance for potential protein adulteration in non-ruminant feed. The EU defines a spectro-colorimetric method as an official control method for the determination of urea in feed, whereas the Association of Official Analytical Chemists (AOAC) in the United States recommends an enzymatic method. Discrepancies between results obtained by these different approaches have been reported, especially at low concentrations. Therefore, we developed and validated two methods for urea determination in compound feed, including pet food, and yeast (Saccharomyces cerevisiae) over a wide concentration range using high-performance liquid chromatography coupled with tandem mass spectrometry (LC-MS/MS) and fluorescence detection (HPLC-FLD) and compared performance with a commercial enzyme kit. Limit of detection (LOD) and limit of quantification (LOQ) were found to be 3 and 8 mg kg−1 for LC-MS/MS and 2 and 7 mg kg−1 for HPLC-FLD, respectively. For both methods, the variation coefficients ranged between 1.4% and 7.2% in ruminant feed used as reference material as well as spiked samples of complete feed for chicken, pet food for dogs and cats, as well as yeast. Recovery rates for spiked samples ranged from 86% to 105%. For real samples of complete feed for poultry, wet and dry pet food for cats and dogs and yeast amounts of urea between < LOD and 200 mg kg−1 relative to a feedingstuff with a moisture content of 12% were found. In comparison with the enzyme kit, the newly developed methods proved to be less time-consuming in sample preparation and more stable regarding matrix effects. [ABSTRACT FROM AUTHOR]

In addition to currently used methods of gas chromatography with flame ionization detector or mass spectroscopy detection (GC–FID and GC–MS) for the analysis of seized heroin, a novel rapid high-performance liquid chromatography with tandem mass spectrometry (HPLC–MS/MS) method for detection and quantification of the main alkaloids was developed. This method for detection and quantification of heroin, papaverine, noscapine, and acetyl thebaol was validated and applied to analysis of seized heroin street samples. The method is rapid (6 min) and implies a low solvent consumption (0.75 mL min−1), suitable as an alternative method for GC–MS for heroin samples stored at elevated temperatures. The method was successfully tested on seized heroin samples. [ABSTRACT FROM AUTHOR]