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BACKGROUND: Glyoxal has been implicated as a significant contributor to the formation of secondary organic aerosols, which play a key role in our ability to estimate the impact of aerosols on climate. Elevated concentrations of glyoxal over remote ocean waters suggests that there is an additional source, distinct from urban and forest environments, which has yet to be identified. Herein, we demonstrate that the ocean can serve as an appreciable source of glyoxal in the atmosphere due to microbiological activity. METHODS AND RESULTS: Based on mass spectrometric analyses of nascent sea spray aerosols and the sea surface microlayer (SSML) of naturally occurring algal blooms, we provide evidence that during the algae death phase phospholipids become enriched in the SSML and undergo autoxidation thereby generating glyoxal as a degradation product. CONCLUSIONS: We propose that the death phase of an algal bloom could serve as an important and currently missing source of glyoxal in the atmosphere.

In order to understand the status of aflatoxin contamination in dried chilli products in Gansu Province and the risk of dietary exposure, a total of 106 samples of dried chilli products from farmers' markets and supermarkets in 14 prefecture-cities of Gansu Province were collected and analysed by isotope dilution liquid chromatography-tandem mass spectrometry. The results showed that the detection rate of aflatoxin in dried chilli products in Gansu Province was 30.2%, and the average level was 1.57 μg/kg. The detection rates of dried chillies, paprika, and chilli powders were 16.7%, 43.6%, and 46.2%, respectively. The detection rates of aflatoxin in dried chilli products from shops and farmers' markets were 22.5% and 40.0%, respectively. The dietary exposure of AFB1 was 0.0001 μg/kg bw/day, and the MOE calculated from its average concentration was 305. [ABSTRACT FROM AUTHOR]

Bioactive compounds in functional foods, medicinal plants and others are considered attractive value-added molecules based on their wide range of bioactivity. It is clear that an important role is occupied by polyphenol, phenolic compounds and others. Urine is an effective biofluid to evaluate and monitor alterations in homeostasis and other processes related to metabolism. The current review provides a detailed description of the formation of urine in human body, various aspects relevant to sampling and analysis of urinary metabolites before presenting recent developments leveraging on metabolite profiling of urine. For the profiling of small molecules in urine, advancement of liquid chromatography mass tandem spectrometry (LC/MS/MS), establishment of standardized chemical fragmentation libraries, computational resources, data-analysis approaches with pattern recognition tools have made it an attractive option. The profiling of urinary metabolites gives an overview of the biomarkers associated with the diet and evaluates its biological effects. Metabolic pathways such as glycolysis, tricarboxylic acid cycle, amino acid metabolism, energy metabolism, purine metabolism and others can be evaluated. Finally, a combination of metabolite profiling with chemical standardization and bioassay in functional food and medicinal plants will likely lead to the identification of new biomarkers and novel biochemical insights. [ABSTRACT FROM AUTHOR]

Despite the great relevance of the neurosteroid allopregnanolone and related isomers to various health conditions, quantification typically involves immunoassay, which suffers from serious issues with cross-reactivity of closely related molecules. This article describes the development and partial validation of a liquid chromatography coupled with tandem mass spectrometry assay for the simultaneous quantification of allopregnanolone, pregnanolone, isopregnanolone, epi-allopregnanolone, and testosterone in the human serum of healthy males and females aged 5–85 years. 1-amino-4-methylpiperazine (AMP) was used as a derivatisation reagent to enhance the ionisation signal. Linearity was calculated at 0.99 with a lower limit of quantification of 10.08 pg/mL for allopregnanolone, along with a linearity of 0.98 and a lower limit of quantification of 42.32 pg/mL for testosterone. Application of the method showed sex and age effects across the lifespan for both allopregnanolone and testosterone, whereas a comparative immunoassay for allopregnanolone was not able to detect differences in the same samples. Our partial validation of this method should provide a new tool for researchers to discover the role of allopregnanolone and its isomers in human health, and how it compares to testosterone and sex hormones. [ABSTRACT FROM AUTHOR]

Abstract Despite the great relevance of the neurosteroid allopregnanolone and related isomers to various health conditions, quantification typically involves immunoassay, which suffers from serious issues with cross-reactivity of closely related molecules. This article describes the development and partial validation of a liquid chromatography coupled with tandem mass spectrometry assay for the simultaneous quantification of allopregnanolone, pregnanolone, isopregnanolone, epi-allopregnanolone, and testosterone in the human serum of healthy males and females aged 5–85 years. 1-amino-4-methylpiperazine (AMP) was used as a derivatisation reagent to enhance the ionisation signal. Linearity was calculated at 0.99 with a lower limit of quantification of 10.08 pg/mL for allopregnanolone, along with a linearity of 0.98 and a lower limit of quantification of 42.32 pg/mL for testosterone. Application of the method showed sex and age effects across the lifespan for both allopregnanolone and testosterone, whereas a comparative immunoassay for allopregnanolone was not able to detect differences in the same samples. Our partial validation of this method should provide a new tool for researchers to discover the role of allopregnanolone and its isomers in human health, and how it compares to testosterone and sex hormones.

Abstract Background There are few reports of kidney disease caused by cryofibrinogen (CF). There are still many unknowns regarding its diagnosis, treatment, and prognosis. Case presentation A woman in her 70s experienced gross hematuria without any triggers; no urinary abnormalities had been previously detected. At the same time, the urine protein level was 5 g; therefore, a renal biopsy was performed. Light microscopy revealed a membranoproliferative glomerulonephritis-like pattern. And the electron microscopic findings were extremely characteristic and specific. Development of ischemic lesions was observed in the lower legs. A skin biopsy performed at the sites of toe necrosis showed fibrinoid necrotizing vasculitis and thrombi in the blood vessels. Eventually, the patient was diagnosed with cryofibrinogenemia (CF-emia) by mass spectrometry. The effect of steroids was limited. Subsequently, the patient’s renal function rapidly deteriorated, and toe necrosis progressed. The patient died after initiation of hemodialysis. Conclusion Although CF-emia is an unknown disease and has been infrequently reported, no reported cases exhibited rapid worsening of toe necrosis and renal function during the same period. Therefore, this case can be said to be the first case of fulminant cryofibrinogenemia. Due to the development of nephropathy, which is likely to be a factor for poor prognosis, establishment of therapeutic strategies is urgently required.

Coconut meat and coconut water have garnered significant attention for their richness in healthful flavonoids. However, the dynamics of flavonoid metabolites in coconut water during different developmental stages remain poorly understood. This study employed the metabolomics approach using liquid chromatography-tandem mass spectrometry (LC-MS/MS) to investigate the changes in flavonoid metabolite profiles in coconut water from two varieties, 'Wenye No.5'(W5) and Hainan local coconut (CK), across six developmental stages. The results showed that a total of 123 flavonoid metabolites including chalcones, dihydroflavonoids, dihydroflavonols, flavonoids, flavonols, flavonoid carboglycosides, and flavanols were identified in the coconut water as compared to the control. The total flavonoid content in both types of coconut water exhibited a decreasing trend with developmental progression, but the total flavonoid content in CK was significantly higher than that in W5. The number of flavonoid metabolites that differed significantly between the W5 and CK groups at different developmental stages were 74, 74, 60, 92, 40 and 54, respectively. KEGG pathway analysis revealed 38 differential metabolites involved in key pathways for flavonoid biosynthesis and secondary metabolite biosynthesis. This study provides new insights into the dynamics of flavonoid metabolites in coconut water and highlights the potential for selecting and breeding high-quality coconuts with enhanced flavonoid content. The findings have implications for the development of coconut-based products with improved nutritional and functional properties. [ABSTRACT FROM AUTHOR]

Copyright of Journal of Food Safety & Quality is the property of Journal of Food Safety & Quality Editorial Department and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Objective Methods Results Conclusion To develop a model based on maternal serum liquid chromatography tandem mass spectrometry (LC–MS/MS) proteins to predict spontaneous preterm birth (sPTB).This nested case–control study used the data from a cohort of 2053 women in China from July 1, 2018, to January 31, 2019. In total, 110 singleton pregnancies at 11–13+6 weeks of pregnancy were used for model development and internal validation. A total of 72 pregnancies at 20–32 weeks from an additional cohort of 2167 women were used to evaluate the scalability of the model. Maternal serum samples were analyzed by LC–MS/MS, and a predictive model was developed using machine learning algorithms.A novel predictive panel with four proteins, including soluble fms‐like tyrosine kinase‐1, matrix metalloproteinase 8, ceruloplasmin, and sex‐hormone‐binding globulin, was developed. The optimal model of logistic regression had an AUC of 0.934, with additional prediction of sPTB in second and third trimester (AUC = 0.868).First‐trimester modeling based on maternal serum LC–MS/MS identifies pregnant women at risk of sPTB, which may provide utility in identifying women at risk at an early stage of pregnancy before clinical presentation to allow for earlier intervention. [ABSTRACT FROM AUTHOR]

Mass spectrometry (MS) is a widely used analytical technique including medical diagnostics, forensic toxicology, food and water analysis. The gold standard for quantifying compounds involves using stable isotope-labeled internal standards (SIL-IS). However, when these standards are not commercially available, are prohibitively expensive, or are extremely difficult to synthesize, alternative external quantification techniques are employed. We hereby present a novel, convenient and cheap quantification approach—quantification via post column infusion (PCI). As a proof of concept, we demonstrated PCI quantification for the immunosuppressant tacrolimus in whole blood using liquid chromatography–tandem mass spectrometry (LC-MS/MS). The validation results met the criteria according to the guideline on bioanalytical method validation of the European Medicine Agency (EMA), achieving imprecisions and inaccuracies with coefficient of variation and relative bias below 15%. Anonymized and leftover whole blood samples from immunosuppressed patients receiving tacrolimus were used for method comparison (PCI quantification vs. conventional internal standard (IS) quantification). Both methods showed strong agreement with a Pearson correlation coefficient of r = 0.9532. This novel PCI quantification technique (using the target analyte itself) expands the quantification options available in MS, providing reliable results, particularly when internal standards are unavailable or unaffordable. With the current paper, we aim to demonstrate that our innovative PCI technique has great potential to overcome practical issues in quantification and to provide guidance on how to incorporate PCI in existing or new LC-MS methods. Moreover, this study demonstrated a more convenient method for correcting matrix effects in comparison to alternative PCI techniques. [ABSTRACT FROM AUTHOR]

17α-Hydroxyprogesterone (17α-OHP) quantification in dried blood spots (DBS) is essential for newborn screening for congenital adrenal hyperplasia (CAH), which is challenging due to its low physiological concentration. The high false-positive rates of immunoassays necessitate the development of more accurate methods. Liquid chromatography tandem mass spectrometry (LC-MS/MS) offers increased specificity and sensitivity, yet standardized procedures for 17α-OHP measurement are required for clinical application. A candidate reference measurement procedure (cRMP) using isotope dilution LC-MS/MS was developed for 17α-OHP quantification in DBS. By utilizing stable isotope-labeled D8-17α-OHP as an internal standard, the cRMP was optimized, covering sample preparation, calibration, and LC-MS/MS analysis. The method performance was validated across several parameters, including precision, accuracy, specificity, detection limits, and matrix effects. Clinical applicability was further assessed through the establishment of reference intervals for healthy newborns. The developed cRMP exhibited a linear range of 1.00 to 80.00 ng/mL for 17α-OHP, with detection and quantification limits of 0.14 ng/mL and 0.52 ng/mL, respectively. Inter- and intraday precision demonstrated coefficients of variation within 1.27 to 5.69%. The recovery rates and matrix effects were well within acceptable limits, ensuring method reliability. Clinical application showed distinct reference intervals for healthy newborns that were unaffected by sex but influenced by weight and gestational age. This method significantly enhances CAH diagnostic accuracy in newborns, providing a valuable tool for clinical laboratories and improving newborn screening program standardization and traceability. [ABSTRACT FROM AUTHOR]

Targeted mass spectrometry (MS) holds promise for precise protein and protein‐representative peptide identification and quantification, enhancing disease diagnosis. However, its clinical application is hindered by complex data analysis and expert review requirements. It is hypothesized that machine learning (ML) models can automate data analysis to accelerate the clinical application of MS. The approach involves an ML‐driven pipeline that extracts statistical and morphological features from an MS target region and feeds these features into ML algorithms to generate and assess predictive models. The findings demonstrate ML prediction models exhibit superior performance when trained on extracted features versus raw spectra intensity data and that random forest models exhibit robust classification performance in both internal and external validation datasets. These models remain effective across varying training dataset sizes and positive sample rates and are enhanced by a nested active learning approach. This approach can thus revolutionize clinical MS applications. [ABSTRACT FROM AUTHOR]

Background: Ketamine is an NMDAR antagonist with aggregating use across many areas of medicine. P450 enzymes heavily metabolise ketamine, where norketamine is a first pass formed metabolite following initial N-demethylation. Serum ketamine monitoring is becoming increasingly important, requiring a sensitive method with a robust lower limit of quantitation. Methods: Samples were prepared using protein precipitation or solid phase extraction. Ion suppression was investigated to optimise sample preparation technique, followed by reverse-phase chromatography coupled with tandem mass spectrometry to analyse extractions using a Waters Xevo TQ-S Micro and associated Acquity chromatography systems. Performance characteristics were analysed to validate the assay. Results: Ketamine and norketamine retention times were 1.28 and 1.23 min, respectively. Ketamine and norketamine precursor ions fragmented into 2 distinguishable product ions (238.14 > 207.18/125.06 and 224.1 > 178.96/124.86). Performance characteristics include an assay recovery of 103.7% (ketamine) and 96.3% (norketamine), lower limit of quantitation 36.2 µg/L (ketamine) and 38.9 µg/L (norketamine), and intra-assay imprecision ≤ 7.04% on average. Conclusions: A robust and reproducible assay with limited sample preparation has been designed and validated. The linearity of the assay covers all ranges of interest reported in the literature. Ion suppression was clearly reduced via use of solid phase extraction. The method will form the basis of ketamine monitoring and providing valuable patient information on tolerance and metabolism. [ABSTRACT FROM AUTHOR]

Copyright of Journal of Food Safety & Quality is the property of Journal of Food Safety & Quality Editorial Department and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Journal of Food Safety & Quality is the property of Journal of Food Safety & Quality Editorial Department and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The use of plant protection products (PPPs) has become fundamental to guarantee excellent field productivity. Nevertheless, their usage presents critical issues, such as the quantity of substances used, the relative toxicity, and the contamination of nearby fields caused by atmospheric drift. This study focuses on the characterization of aerosol droplets of PPPs produced by spraying a chemical marker, fluorescein, with an orchard airblast sprayer equipped with conventional hollow cone (HC) and anti-drift air inclusion (AI) nozzles, using a wind tunnel as a controlled environment. A particle/droplet image analysis was employed to study the droplet production of the nozzles, while a liquid chromatography tandem mass spectrometry (HPLC-MS/MS) analysis allowed us to evaluate samples collected using a cascade impactor located at 5 m, 10 m, and 20 m from the emission point. Overall, HC nozzles are very accurate at producing specific drop size distributions (DSDs), while AI nozzles produce a much wider DSD, concentrating the largest part of the distributed volume into droplets of a larger size. The marker concentration was much lower for the AI nozzles compared to the HC nozzles; moreover, the two nozzles show a similar trend in the coarse droplet range, while significantly differing in the fine droplet spectrum. [ABSTRACT FROM AUTHOR]

Targeted mass spectrometry (MS) holds promise for precise protein and protein‐representative peptide identification and quantification, enhancing disease diagnosis. However, its clinical application is hindered by complex data analysis and expert review requirements. It is hypothesized that machine learning (ML) models can automate data analysis to accelerate the clinical application of MS. The approach involves an ML‐driven pipeline that extracts statistical and morphological features from an MS target region and feeds these features into ML algorithms to generate and assess predictive models. The findings demonstrate ML prediction models exhibit superior performance when trained on extracted features versus raw spectra intensity data and that random forest models exhibit robust classification performance in both internal and external validation datasets. These models remain effective across varying training dataset sizes and positive sample rates and are enhanced by a nested active learning approach. This approach can thus revolutionize clinical MS applications.

Background: Glyoxal has been implicated as a significant contributor to the formation of secondary organic aerosols, which play a key role in our ability to estimate the impact of aerosols on climate. Elevated concentrations of glyoxal over remote ocean waters suggests that there is an additional source, distinct from urban and forest environments, which has yet to be identified. Herein, we demonstrate that the ocean can serve as an appreciable source of glyoxal in the atmosphere due to microbiological activity. Methods and Results: Based on mass spectrometric analyses of nascent sea spray aerosols and the sea surface microlayer (SSML) of naturally occurring algal blooms, we provide evidence that during the algae death phase phospholipids become enriched in the SSML and undergo autoxidation thereby generating glyoxal as a degradation product. Conclusions: We propose that the death phase of an algal bloom could serve as an important and currently missing source of glyoxal in the atmosphere.

In this paper, a natural deep eutectic solvent (NADES)-based liquid phase microextraction (LPME) of 20 pharmaceuticals from urine, employing liquid chromatography tandem mass spectrometry (LC-MS/MS) for precise quantification, has been developed. The chromatographic gradient was accurately evaluated to ensure the effective separation of tramadol, an opioid receptor agonist, and o-desmethylvenlafaxine, one active metabolite of the antidepressant venlafaxine, both compounds sharing identical molecular mass for the precursor ion (Q1: 264.2 m/z) and fragmentation patterns (Quantifier ion: 58.2 m/z; qualifier ion: 246.0 m/z). NADES consisted of menthol-octanoic acid in a molar ratio of 1:2. Using the appropriate extraction conditions, the developed methodology provided appropriate LOQ values, ranging from 15 to 208 ng L–1, with reasonable RSD values (below 11 %), recoveries ranging from 64 to 120 % and preconcentration factors up to 66.6 folds. Application of the developed method to the analysis of urine samples served to highlight its usefulness. An AGREEprep score of 0.64 was obtained despite the demand for substantial sample volumes and the use of LC-MS/MS for analyte determination.

Despite being a minimally invasive sample source, dried blood spots (DBS) generally pose the challenge of efficient sample extraction for broad metabolomics applications. This is particularly true for the quantification of steroids using non-derivatized liquid chromatography tandem mass spectrometry assays. To address these limitations, we have demonstrated the use of electric field as a driver for sample preparation from DBS samples to simultaneously quantify testosterone (T), 17α-hydroxyprogesterone (17-OHP), progesterone (P), and cortisol (C), using both standard electroporation cuvettes, as well as a novel custom vertical electric field setup. Our findings, backed by computational modeling, show that a 10V DC application for 180 s can draw out twice the amount of the aforementioned steroids from both Whatman-903 and DMPK-C sample collection cards using our novel device when compared to standard solvent-based collection methods. This study not only introduces the use of electric field for sample preparation for metabolomics, but additionally introduces a novel device that eliminates the electric double layer effect in the process.

Mass spectrometry (MS) is a widely used analytical technique including medical diagnostics, forensic toxicology, food and water analysis. The gold standard for quantifying compounds involves using stable isotope-labeled internal standards (SIL-IS). However, when these standards are not commercially available, are prohibitively expensive, or are extremely difficult to synthesize, alternative external quantification techniques are employed. We hereby present a novel, convenient and cheap quantification approach—quantification via post column infusion (PCI). As a proof of concept, we demonstrated PCI quantification for the immunosuppressant tacrolimus in whole blood using liquid chromatography–tandem mass spectrometry (LC-MS/MS). The validation results met the criteria according to the guideline on bioanalytical method validation of the European Medicine Agency (EMA), achieving imprecisions and inaccuracies with coefficient of variation and relative bias below 15%. Anonymized and leftover whole blood samples from immunosuppressed patients receiving tacrolimus were used for method comparison (PCI quantification vs. conventional internal standard (IS) quantification). Both methods showed strong agreement with a Pearson correlation coefficient of r = 0.9532. This novel PCI quantification technique (using the target analyte itself) expands the quantification options available in MS, providing reliable results, particularly when internal standards are unavailable or unaffordable. With the current paper, we aim to demonstrate that our innovative PCI technique has great potential to overcome practical issues in quantification and to provide guidance on how to incorporate PCI in existing or new LC-MS methods. Moreover, this study demonstrated a more convenient method for correcting matrix effects in comparison to alternative PCI techniques.

Ixazomib citrate (IC) is the first oral selective proteosome inhibitor for treating multiple myeloma. IC is prone to degradation due to its oxidative deboronation and the amide bond, affecting patient health, drug quality, and efficacy. The stability of IC is crucial during drug development as it guides the inherent stability of the molecule, its degradation pathways, packing materials, and formulation development. Following the International Conference on Harmonization (ICH) Q1A (R2) and Q1B, a stability study were performed for both solution and solid-state stress studies. Under oxidative and alkaline conditions, 3 degradation products (DPs) were identified, separated, and method-validated according to ICH Q2 (R1) guidelines. From the Design Expert statistical tool, the Central Composite Design was used to optimize the final analytical method conditions, where the p-values for the model are < 0.05%. Green analytical chemistry has significantly reduced the use of hazardous organic solvents without losing chromatographic performance. The green separation and quantification of DPs and IC on Ultra Performance Liquid Chromatography (UPLC) using an Inert-Sustain C8 (50×3.0) mm 2.0 µm column with gradient elution using 10 mM ammonium acetate buffer (pH 5.0) and ethanol at a flow rate of 0.5 mL/min and detection at 230 nm. The results of green assessment tools like GAPI, AGREE, and Analytical eco-scale found that the method is excellent for the greenness of utilizing ethanol as a solvent, shorter runtime, and lesser waste. The method was validated as per ICH Q2 guidelines, and the results found it is sensitive, precise, accurate, robust, and linear for its intended use. The method is suitable for quantifying IC and its DPs from 2.0 to 150 µg/mL with R2 values of 0.9996 with a detection limit of 1.0 µg/mL. The plausible degradation structures and pathways of DPs were outlined using tandem mass spectra employed on LC-QTOF-MS/MS in both ESI positive and negative modes. The mechanistic explanation for establishing DPs was explained in detail. The ADMET Predictor™ software predicted the physicochemical and ADMET properties. The toxicity profile reveals that DP2 and DP3 are teratogenic, while D1 and D3 show phospholipidosis.

The presence of coccidiostats in meat products represents an important topic because of the animal administration of these substances, authorized as feed additives for targeted species, in order to prevent and inhibit coccidiosis. Coccidiostats include both ionophores and synthetic molecules characterized by different chemical–physical properties such as polarity. Meat is a matrix characterized by many interfering compound groups, such as proteins, phospholipids, and fats. High‐performance liquid chromatography (HPLC) coupled to mass spectrometry (MS) analysis allows the required selectivity and sensitivity for discriminating analytes and matrix interferences. For these reasons, an LC–MS/MS method for the analysis of coccidiostats in meat products was developed without SPE purification steps. The correct analyte quantification is allowed by matrix‐matched calibration. The method validation was performed by the replicated analysis of spiked meat samples at two different concentration levels (limit of quantification—LOQ—and a 10 times LOQ) in order to evaluate method recovery and repeatability, plus spiked samples at higher concentrations up to 10,000 μg/kg. Moreover, the metrological approach was used for the calculation of method uncertainty. The application of the developed method to real samples evidenced the presence of some non‐ionophores coccidiostats in the meat and liver of chicken and rabbit species. Although, the determined concentration was below the established MRLs, the monitoring of coccidiostats in the meat supply chain is confirmed as a good strategy in order to safeguard consumer health. [ABSTRACT FROM AUTHOR]

Copyright of Journal of Modern Laboratory Medicine is the property of Journal of Modern Laboratory Medicine Editorial Department and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

BackgroundThe retinol isotope dilution (RID) method has been used to evaluate vitamin A (VA) status in healthy adults and children in low- and middle-income countries (LMIC) and to assess the efficacy of various VA interventions.ObjectiveThe study was designed to examine whether dried serum spots (DSS) can be applied to RID when conducting VA total body store (TBS) assessments in community settings.MethodsFour days after an oral dose of 0.4 mg [13C10]retinyl acetate was administered to Filipino children (12-18 mo), a single blood draw was divided to isolate both serum and plasma. Serum (40 μL) was spotted and dried on Whatman 903 cards and shipped at ambient temperature whereas liquid plasma (LP) was frozen at -80°C and shipped on dry ice. The VA tracer to tracee ratio from DSS and LP was quantified by LC-MS/MS. Comparisons between DSS and LP paired samples (n = 72) were made for [13C10]retinol specific activity (SAp) by Pearson's correlation and for VA TBS by Bland-Altman analysis.ResultsThe sum of 3 coextracted DSS were required to consistently detect [13C10]retinol above the LC-MS/MS limit of quantitation (LOQ). [13C10]retinol SAp from DSS was highly correlated with SAp from LP (r = 0.945; P

Background: Recent studies from targeted and untargeted metabolomics have consistently revealed that diet-related metabolites, including carnitine (C0), several species of acylcarnitines (AcyCNs), amino acids, ceramides, and lysophosphatidylcholines (LPCs) may serve as potential multiple myeloma (MM) biomarkers. However, most of these approaches had some intrinsic limitations, namely low reproducibility and compromising the accuracy of the results. Objective: This study developed and validated a precise, efficient, and reliable liquid chromatography tandem mass spectrometric (LC-MS/MS) method for measuring these 28 metabolic risk factors in human serum. Design: This method employed isopropanol to extract the metabolites from serum, gradient elution on a hydrophilic interaction liquid chromatographic column (HILIC) for chromatographic separation, and multiple reaction monitor (MRM) mode with positive electrospray ionization (ESI) for mass spectrometric detection. Results: The correlation coefficients of linear response for this method were more than 0.9984. Analytical recoveries ranged from 91.3 to 106.3%, averaging 99.5%. The intra-run and total coefficients of variation were 1.1–5.9% and 2.0–9.6%, respectively. We have simultaneously determined the serological levels of C0, several subclasses of AcyCNs, amino acids, ceramides, and LPCs within 15 min for the first time. Conclusion: The established LC-MS/MS method was accurate, sensitive, efficient, and could be valuable in providing insights into the association between diet patterns and MM disease and added value in further clinical research.

This study establishes an analytical method for simultaneous determination of 19 Succinate dehydrogenase inhibitor fungicides pesticide residues in Green coffee by QuEChERS-Liquid chromatography tandem mass spectrometry. The Green coffee powder samples were extracted with acetonitrile by Homogenizer, the supernatant were purified by Magnesium sulfate anhydrous、PSA and C18, liquid chromatograhy - tandem mass spectrometry were used for analyzing 19 Succinate dehydrogenase inhibitor fungicides pesticide residues at positive ion mode. The results showed that the calibration curves of 19 targets showed good linearity with correlation coefficients of above 0.995 0 in the range of 1~100 ng/mL, the recoveries of 19 pesticides were 79.6%~109.4% and the relative standard deviations(RSD, n=6) were in the range of 1.4%~9.7% at spiked levels of 0.01、0.05 and 0.1 mg/kg. Limit of quantitation (LOQ) of all the tested pesticides were 0.51~4.60 μg/kg. This method has good linear relations, excellent stable and sensitive, accuracy and precision meet the requirement of quantitative analysis, it is suitable for quantitative analysis of 19 Succinate dehydrogenase inhibitor fungicides pesticide residues in Green coffee.

The use of plant protection products (PPPs) has become fundamental to guarantee excellent field productivity. Nevertheless, their usage presents critical issues, such as the quantity of substances used, the relative toxicity, and the contamination of nearby fields caused by atmospheric drift. This study focuses on the characterization of aerosol droplets of PPPs produced by spraying a chemical marker, fluorescein, with an orchard airblast sprayer equipped with conventional hollow cone (HC) and anti-drift air inclusion (AI) nozzles, using a wind tunnel as a controlled environment. A particle/droplet image analysis was employed to study the droplet production of the nozzles, while a liquid chromatography tandem mass spectrometry (HPLC-MS/MS) analysis allowed us to evaluate samples collected using a cascade impactor located at 5 m, 10 m, and 20 m from the emission point. Overall, HC nozzles are very accurate at producing specific drop size distributions (DSDs), while AI nozzles produce a much wider DSD, concentrating the largest part of the distributed volume into droplets of a larger size. The marker concentration was much lower for the AI nozzles compared to the HC nozzles; moreover, the two nozzles show a similar trend in the coarse droplet range, while significantly differing in the fine droplet spectrum.

Purpose: To analyze serum estradiol (E2) and estrone (E1) during letrozole treatment and their association to Quality of Life (QoL) and side-effects. Methods: Postmenopausal breast cancer patients starting adjuvant letrozole were eligible. Serum samples were taken at baseline, three, and 12 months. E2 and FSH were measured with routine chemiluminescent immunoassays. E2 and E1 were analyzed after trial completion with a highly sensitive liquid chromatography-tandem mass spectrometry method (LC–MS/MS) with lower limits of quantification (LLOQ) of 5 pmol/L. QoL was measured at baseline and at 12 months with the EORTC QLQ-C30 and QLQ-BR23 and the Women's Health questionnaires, and menopause-related symptoms with the modified Kupperman Index. Results: Of 100 screened patients 90 completed the trial. Baseline mean LC–MS/MS E2 and E1 were 12 pmol/L (range < 5–57) and 66 pmol/L (< 5–226), respectively. E2 levels measured by immunoassay and LC–MS/MS showed no correlation. E2 and E1 were completely suppressed by letrozole except for one occasion (E1 11 pmol/L at 3 months). Pain, side effects of systemic therapy, vasomotor symptoms, joint and muscle aches, and vaginal dryness increased during letrozole treatment. A high baseline E2 was significantly associated with increased aching joints and muscles, but not with the other side effects. Conclusions: Letrozole supresses E2 and E1 completely below the LLOQ of the LC–MS/MS in postmenopausal women. High pre-treatment E2 levels were associated with more joint and muscle pain during letrozole. Automated immunoassays are unsuitable for E2 monitoring during letrozole therapy due to poor sensitivity. [ABSTRACT FROM AUTHOR]

ObjectiveA simple and rapid method for the simultaneous determination of 7 kinds of fishery anesthetics and 2 kinds of sedatives in freshwater fish was developed using liquid chromatography tandem mass spectrometry （LC-MS/MS）.MethodsThe fish sample was adsorbed with C18 and PSA after extracted with acetonitrile， then centrifuged and diluted with water， detected in the positive / negative ion mode. Quantitative analysis was carried out by isotope internal standard method with matrix calibration curve.ResultsUnder the optimized conditions， good linearities for 7 kinds of fishery anesthetics and 2 kinds of sedatives were obtained in the range of 0.5-50 μg/L （MS-222 was 0.05-5.0 μg/L） with the correlation coefficients（r） higher than 0.999. The limits of detection were 0.02-0.4 μg/kg （S/N=3）. Recoveries at three spiked levels ranged from 87.0% to 117.3%. And the relative standard deviations was 2.5%-8.2%.ConclusionThis method was simple， sensitive and selective， which could be applied to the rapid qualitative and quantitative analysis of the 7 kinds of fishery anesthetics and 2 kinds of sedatives in freshwater fish.

Background: Eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) have been suggested to play roles in various diseases, yet there is little data on their changes in patients with non-small-cell lung cancer (NSCLC). A simple LC-MS/MS method for EPA and DHA determination is critical to exploring EPA and DHA level changes in NSCLC patients. Methods: 25 µL of serum was mixed with 25 µL of internal standard working solution, and then 450 µL of acetonitrile for protein precipitation. After vortex and centrifugation, the supernatant was directly used for LC-MS/MS analysis. The method was well validated with linearity, precision, recovery, and matrix effect. The concentrations of EPA and DHA in serum samples from 211 NSCLC patients and 227 healthy controls were determined by this LC-MS/MS method. Results: Good separation and reliable quantification of EPA and DHA in serum samples were achieved by our method. Compared with healthy controls, serum EPA and DHA were significantly reduced in both adenocarcinoma and squamous cell carcinoma patients. The concentrations of EPA and DHA showed a progressive decrease in healthy controls, early- and advanced-stage NSCLC patients. Conclusions: This study identified significant reductions in serum EPA and DHA in NSCLC patients through the development of an LC-MS/MS method.

Background: Steroids play a key role in numerous physiological processes. Steroid determination is a useful tool to explore various endocrine diseases. Because of its specificity, mass spectrometry is considered to be a reference method for the determination of steroids in serum compared to radioimmunoassay. This technology could progress towards more automation for the optimal organization of clinical laboratories and ultimately for the benefit of patients. Methods: A fully automated ultra-high-performance liquid chromatography-tandem mass spectrometry method was developed and fully validated to determine five steroids in serum. Sample preparation was based on protein precipitation with filtration followed by online solid phase extraction. Chromatographic separation was performed using a biphenyl stationary phase. Results: The method was successfully validated according to European Medicine Agency guidelines. Coefficients of variation did not exceed, respectively, 8.4% and 8.1% for intra- and inter-assay precision. Method comparison with radioimmunoassay showed a proportional bias for all compounds, except for testosterone in men. Comparison with another LC-MS/MS method demonstrated acceptable concordance for all steroids, although a small bias was observed for androstenedione. Conclusion: The novelty of this method is that it has been fully automated. Automation provides benefits in traceability and allows significant savings in cost and time.

Therapeutic drug monitoring (TDM) is a specialized area of laboratory medicine which involves the measurement of drug concentrations in biological fluids with the aim of optimizing efficacy and reducing side effects, possibly modifying the drug dose to keep the plasma concentration within the therapeutic range. Plasma and/or whole blood, usually obtained by venipuncture, are the "gold standard" matrices for TDM. Microsampling, commonly used for newborn screening, could also be a convenient alternative to traditional sampling techniques for pharmacokinetics (PK) studies and TDM, helping to overcome practical problems and offering less invasive options to patients. Although technical limitations have hampered the use of microsampling in these fields, innovative techniques such as 3-D dried blood spheroids, volumetric absorptive microsampling (VAMS), dried plasma spots (DPS), and various microfluidic devices (MDS) can now offer reliable alternatives to traditional samples. The application of microsampling in routine clinical pharmacology is also hampered by the need for instrumentation capable of quantifying analytes in small volumes with sufficient sensitivity. The combination of microsampling with high-sensitivity analytical techniques, such as liquid chromatography coupled with tandem mass spectrometry (LC-MS/MS), is particularly effective in ensuring high accuracy and sensitivity from very small sample volumes. This manuscript provides a critical review of the currently available microsampling devices for both whole blood and other biological fluids, such as plasma, urine, breast milk, and saliva. The purpose is to provide useful information in the scientific community to laboratory personnel, clinicians, and researchers interested in implementing the use of microsampling in their routine clinical practice. [ABSTRACT FROM AUTHOR]

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Copyright of Modern Food Science & Technology is the property of Editorial Office of Modern Food Science & Technology and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Per- and polyfluoroalkyl substances (PFAS) are widespread and highly persistent organic chemicals with adverse health effects. The US Environmental Protection Agency has issued health advisory limits of 70 ng/L for aqueous concentrations of PFOA + PFOS. In the Colorado Springs, Colorado (USA), metro area, the Widefield Aquifer (groundwater) and Fountain Creek Watershed (surface water) have been contaminated by PFAS from aqueous film-forming foams. Here we present the concentrations of selected linear and branched isomers of legacy PFAS found in surface water (n = 95), soil (n = 83), and sediment (n = 34) samples collected from several creeks of the Fountain Creek Watershed. Collected samples were prepared for high-performance liquid chromatography tandem mass spectrometry (LC/MS/MS) analysis via liquid/liquid extraction and/or solid phase extraction (SPE). This dataset includes the geographic locations of sampled creeks, LC/MS/MS instrumental conditions, method verification data including percent recovery to assess method accuracy and background contamination of PFAS in laboratory reagents and supplies, and determined concentrations of PFAS in water, soil, and sediment samples. These locations were surveyed monthly for a full year and provide a rich dataset to assess influence of sampling location, temporal variability in concentration, and overall contaminant persistence.

In females, a hallmark of puberty is the luteinizing hormone (LH) surge that triggers ovulation. Puberty initiates estrogen positive feedback onto hypothalamic circuits, which underlie the stimulation of gonadotropin releasing hormone (GnRH) neurons. In reproductively mature female rodents, both estradiol (E2) and progesterone (P4) signaling are necessary to stimulate the surge release of GnRH and LH. Estradiol membrane-initiated signaling facilitates progesterone (neuroP) synthesis in hypothalamic astrocytes, which act on E2-induced progesterone receptors (PGR) to stimulate kisspeptin release, thereby activating GnRH release. How the brain changes during puberty to allow estrogen positive feedback remains unknown. In the current study, we hypothesized that a critical step in estrogen positive feedback was the ability for estradiol-induced neuroP synthesis. To test this idea, hypothalamic neuroP levels were measured in groups of prepubertal, pubertal and young adult female Long Evans rats. Steroids were measured with liquid chromatography tandem mass spectrometry (LC-MS/MS). Hypothalamic neuroP increases from pre-puberty to young adulthood in both gonad-intact females and ovariectomized rats treated with E2. The pubertal development of hypothalamic E2-facilitated progesterone synthesis appears to be one of the neural switches facilitating reproductive maturation.

Objective: This study aimed to investigate the residues and risk assessment of pesticides in peach gum. Methods: The quantitative analysis of 44 pesticide residues in peach gum was established based on liquid chromatography tandem-mass spectrometry （LC-MS/MS）, and the pesticide residues in 173 peach gum samples were detected as well as the risk assessment of pesticide residues. Results: The limits of detection （LOD） and the limits of quantification （LOQ） of 44 kinds of pesticides in this quantitative method were between 0.05~1.80 μg/kg and 0.20~2.42 μg/kg, respectively. Recoveries of these pesticides ranged from 61.77%~119.48%. In 173 peach gum samples, 22 out of 44 pesticides were detected and the total detection rate of pesticides in peach gum was 98.8%. The detection rate of difenoconazole was the highest （95%）, followed by chlorpyrifos （54%）, carbendazim （34%）, furamethoxam （32%） and pyraclostrobin （19%）. The average residue of difenoconazole in different peach gum samples was the highest （0.332 mg/kg）, followed by furamethoxam （0.093 mg/kg）, carbendazim （0.061 mg/kg） and chlorpyrifos （0.033 mg/kg）. Conclusion: Pesticide residues in peach gum were related to the usage of pesticides in peach production and were at a low risk level. It is recommended to pick peach gum from August to October.

Despite its critical role in neurodevelopment and brain function, vitamin D (vit-D) homeostasis, metabolism, and kinetics within the central nervous system remain largely undetermined. Thus, it is of critical importance to establish an accurate, highly sensitive, and reproducible method to quantitate vit-D in brain tissue. Here, we present a novel liquid chromatography tandem mass spectrometry (LC-MS/MS) method and for the first time, demonstrate detection of seven major vit-D metabolites in brain tissues of C57BL/6J wild-type mice, namely 1,25(OH)2D3, 3-epi-1,25(OH)2D3, 1,25(OH)2D2, 25(OH)D3, 25(OH)D2, 24,25(OH)2D3, and 24,25(OH)2D2. Chromatographic separation was achieved on a pentaflurophenyl column with 3 mM ammonium formate water/methanol [A] and 3 mM ammonium formate methanol/isopropanol [B] mobile phase components. Detection was by positive ion electrospray tandem mass spectrometry with the EVOQ elite triple quadrupole mass spectrometer with an Advance ultra-high-performance liquid chromatograph and online extraction system. Calibration standards of each metabolite prepared in brain matrices were used to validate the detection range, precision, accuracy, and recovery. Isotopically labelled analogues, 1,25(OH)2D3-d3, 25(OH)D3-c5, and 24,25(OH)2D3-d6, served as the internal standards for the closest molecular-related metabolite in all measurements. Standards between 1 fg/mL and 10 ng/mL were injected with a resulting linear range between 0.001 and 1 ng, with an LLOD and LLOQ of 1 pg/mL and 12.5 pg/mL, respectively. The intra-/inter-day precision and accuracy for measuring brain vit-D metabolites ranged between 0.12–11.53% and 0.28–9.11%, respectively. Recovery in acetonitrile ranged between 99.09 and 106.92% for all metabolites. Collectively, the sensitivity and efficiency of our method supersedes previously reported protocols used to measure vit-D and to our knowledge, the first protocol to reveal the abundance of 25(OH)D2, 1,25(OH)D2, and 24,25(OH)2D2, in brain tissue of any species. This technique may be important in supporting the future advancement of pre-clinical research into the function of vit-D in neurophysiological and neuropsychiatric disorders, and neurodegeneration. [ABSTRACT FROM AUTHOR]

Oxylipins derived from the cyclooxygenase (COX) and lipoxygenase (LOX) pathways of the arachidonic acid (ARA) cascade are essential for the regulation of the inflammatory response and many other physiological functions. Comprehensive analytical methods comprised of oxylipin and protein abundance analysis are required to fully understand mechanisms leading to changes within these pathways. Here, we describe the development of a quantitative multi-omics approach combining liquid chromatography tandem mass spectrometry–based targeted oxylipin metabolomics and proteomics. As the first targeted proteomics method to cover these pathways, it enables the quantitative analysis of all human COX (COX-1 and COX-2) and relevant LOX pathway enzymes (5-LOX, 12-LOX, 15-LOX, 15-LOX-2, and FLAP) in parallel to the analysis of 239 oxylipins with our targeted oxylipin metabolomics method from a single sample. The detailed comparison between MRM3 and classical MRM-based detection in proteomics showed increased selectivity for MRM3, while MRM performed better in terms of sensitivity (LLOQ, 16–122 pM vs. 75–840 pM for the same peptides), linear range (up to 1.5–7.4 μM vs. 4–368 nM), and multiplexing capacities. Thus, the MRM mode was more favorable for this pathway analysis. With this sensitive multi-omics approach, we comprehensively characterized oxylipin and protein patterns in the human monocytic cell line THP-1 and differently polarized primary macrophages. Finally, the quantification of changes in protein and oxylipin levels induced by lipopolysaccharide stimulation and pharmaceutical treatment demonstrates its usefulness to study molecular modes of action involved in the modulation of the ARA cascade. [ABSTRACT FROM AUTHOR]

Following the bovine spongiform encephalopathy (BSE) in 2001, processed animal proteins (PAPs) reintroduction is envisaged in non-ruminant feed thanks to their high protein content, easy availability and cost-effective characteristics. PAPs must be submitted to rendering practices, providing sterilization of products, under standardized conditions of temperature and pressure, according to Regulation (EC) No 142/2011. However, the chemical risk associated to these raw materials has been never evaluated. The aim of this study was to develop and validate a reliable liquid chromatography tandem mass spectrometry (LC–MS/MS) method for the determination and quantification of tetracycline residues in PAPs at µg kg−1 level. The LC–MS/MS method performances were evaluated in terms of specificity, linearity (25–500 µg kg−1), limit of quantitation (LOQ) (25 µg kg−1), accuracy and precision (CV% < 25%), uncertainty, recovery (80–120%) and ruggedness. All the evaluated parameters fulfilled the analytical performance criteria, and the validated LC–MS/MS method fits for purpose as confirmatory method on the occurrence of residues (µg kg−1) of tetracyclines in PAPs. PAPs are a powerful product which could be used both as raw materials in feed and in organic fertilizer production in a circular economy context. Therefore, the lack of regulation and control over antibiotic occurrence should be implemented to avoid a misuse and an increment of antibiotic resistance pressure over the environment and to ensure safety of the feed and food chain. [ABSTRACT FROM AUTHOR]

ObjectiveA high-throughput method for simultaneous determination of 67 herbicide residues in oilseeds and oils by liquid chromatography-tandem mass spectrometry combined with dispersive solid phase extraction was established.MethodsPeanut， soybean， rapeseed and their oil were extracted with 1% formic acid-acetonitrile， and then purified by ethylenediamine-N-propyl and anhydrous MgSO4 dispersed solid phase extraction. Methanol and 5 mmol/L ammonium acetate （containing 0.1% formic acid） were used as mobile phases for gradient elution. C18 column was used for separation， positive and negative ion mode of ESI ion source was used for simultaneous multi-reaction monitoring （MRM）. And matrix standard curve external standard method was used for quantification.ResultsUnder different substrates， the linear range of 67 herbicides was from 0.000 5 to 0.08 mg/L， the correlation coefficients （R2） were all above 0.992， and the limits of detection （LODs） were 0.005~0.02 mg/kg. The recoveries of three spiked levels （LOD， 2LOD and 10LOD） were between 62.3% and 118.1% with RSD （n=6） less than 15%.ConclusionThis method is stable， specific， sensitive and accurate， and can be used for qualitative and quantitative detection of herbicides in oilseeds and oils.