Determination of 24 sulfonamide antibiotics in instant pastries by modified QuEChERS coupled with ultra performance liquid chromatography-tandem mass spectrometry.

There were few reports about antibiotic residues in egg-containing products. In the study, an effective method for the simultaneous determination of 24 sulfonamide antibiotics in two instant pastries based on a modified QuEChERS sample preparation technique coupled with ultra performance liquid chromatography-tandem mass spectrometry was developed. The results show that the average recoveries of the SAs at 5, 10, and 50 µg kg-1 levels were 67.6%-103.8%, with relative standard deviations (RSD) of 0.80-9.23%. The limit of detections (LODs) and limit of quantitations (LOQs) were 0.01-0.14 µg kg-1 and 0.02-0.45 µg kg-1, respectively. This method was suitable for analysis of 24 SAs in instant pastries.

Developing a hydroxyl-functionalized magnetic porous organic polymer combined with HPLC-MS/MS for determining 31 amide herbicides in fruit wine.

More and more attention has been paid to undesirable chemical contaminants from food raw materials and ingredients. The study aimed to fabricate novel hydroxyl-functionalized magnetic porous organic polymer Fe3O4@SiO2-NH2@Ph-POP and explore its use as magnetic adsorbents for magnetic solid-phase extraction (MSPE) for extracting 31 amide herbicides from fruit wine samples prior to high-performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS). Several operational parameters were optimized and the as-prepared magnetic polymer displayed favorable extraction efficiency. The method also showed low limits of detection (0.015-1.412 µg·L-1) and limits of quantitation (0.049-4.707 µg·L-1). Recoveries for all of the herbicides in four different spiked level samples were between 65.06 % and 101.95 % with intra-day and inter-day relative standard deviations less than 9.89 % and 10.54 %, respectively. The proposed MSPE-HPLC-MS/MS method was successfully applied to simultaneously determine 31 amide herbicides in fruit wine.

Uptake and Transport of Different Concentrations of PPCPs by Vegetables.

In many parts of the world, water resources are scarce or even extremely scarce, and the reuse of water resources has become mainstream in today's world. Many regions use treated wastewater for agricultural irrigation, aquaculture, and other activities. However, in recent years, wastewater has been found to contain large amounts of pharmaceuticals and personal care products (PPCPs). Therefore, there is a potential risk of PPCPs being transported in the environment and affecting human health. In this study, we compared the uptake, transport, and accumulation of 27 PPCPs in three types of sprouts (radish, buckwheat, and okra).The bioaccumulation of amantadine, diphenhydramine, chlorpheniramine maleate, sibutramine, hemosibutramine, chlorosibutramine, N-monomethyl sibutramine, N, N-desmethyl sibutramine, and carbamazepine was found to be significantly higher in plants grown for 12 days in media containing 0.5, 5.0, and 50.0 ng/mL PPCPs. With increasing concentration of PPCPs in the culture solution, the amount of PPCPs absorbed by plants and the degree of accumulation also showed an increasing trend. At the same time, it was demonstrated that there was an obvious uptake transfer phenomenon of PPCPs by plants, and the trend of uptake transfer became more and more obvious as the concentration of external environmental pollutants increased. In addition, amantadine, chlorpheniramine maleate, carbamazepine, N, N-desmethyl sibutramine, hemosibutramine, and chlorosibutramine showed more active translocation in some plants (TF > 1.0).

Determination of 12 anti-obesity drugs in human plasma by a 96-well protein precipitation plate using HPLC-MS.

An analytical method was developed and validated for the simultaneous determination of 12 anti-obesity drugs (methylephedrine (MER), amphetamine (AMP), fenfluramine (FEN), bupropion (BUP), fluoxetine (FLU), sibutramine (SIBU), bisacodyl (BISA), bumetanide (BUM), lovastatin (LOVA), simvastatin (SIM), rimonabant (RIMO), and fenofibrate (FENO)) in human plasma by a 96-well protein precipitation plate combined with high-performance liquid chromatography-mass spectrometry (HPLC-MS/MS). The 96-well protein precipitation plate was chosen for simultaneous pretreatment of large sample volumes, making the whole process more efficient and faster. Drugs were separated on an Agilent Poroshell 120 EC-C18 column, and detected by MS/MS under multiple reaction monitoring (MRM) mode. The developed method was validated in terms of linearity, matrix effect, accuracy and precision. A good linearity was obtained in the range of 0.1-20.0 ng mL-1 for fenfluramine, bupropion, fluoxetine, sibutramine, bisacodyl, and rimonabant; and 0.5-20.0 ng mL-1 for methylephedrine, amphetamine, bumetanide, lovastatin, simvastatin, and fenofibrate with a correlation coefficient above 0.995. The method was fully validated with an acceptable accuracy of 75.63-108.21%, matrix effect of 80.41-117.71% except for fenofibrate (76.07% at low concentration levels), and precision of 0.32-13.12%. Owing to the advantages of simple operation, high accuracy and sensitivity, this method is suitable for the rapid and simultaneous detection of 12 anti-obesity drugs in human plasma, providing support for clinically monitoring the development of adverse reactions and guiding the rational and appropriate use of weight-loss drugs for obese people.

Simultaneous Determination of Six Immunosuppressants in Human Whole Blood by HPLC-MS/MS Using a Modified QuEChERS Method.

A high-performance liquid chromatography-tandem mass spectrometry method was established for the simultaneous determination of mycophenolic acid, mycophenolate mofetil, tacrolimus, rapamycin, everolimus and pimecrolimus in human whole blood by optimizing the QuEChERS (Quick, Easy, Cheap, Effective, Rugged, and Safe) preparation method. Whole blood was extracted into ethyl acetate, salted out with anhydrous magnesium sulfate, and purified with ethylenediamine-N-propyl silane adsorbent. The supernatant was evaporated under nitrogen until dry and finally reconstituted in methanol. Chromatographic separation was performed on an Agilent Poroshell 120 EC-C18 column in methanol (mobile phase A)-water (optimized for 0.1% acetic acid and 10 mM ammonium acetate, mobile phase B) at a 0.3 mL·min−1 flow rate. Electrospray ionization and positive ion multiple reaction monitoring were used for detection. The time for of analysis was 13 min. The calibration curves range of tacrolimus, rapamycin, everolimus and pimecrolimus were in the range of 1−100 ng·mL−1, mycophenolate mofetil in the range of 0.1−10 ng·mL−1 and mycophenolic acid at 10−1000 ng·mL−1. All correlation coefficients were >0.993. The coefficients of variation (CV, %) for inter-day and intra-day precision were less than 10%, while the spiked recoveries were in the range of 92.1% to 116%. Our method was rapid, sensitive, specific, and reproducible for the simultaneous determination of six immunosuppressants in human whole blood. Importantly, our approach can be used to monitor drug concentrations in the blood to facilitate disease treatment.

Maternal exposure to triclosan during lactation alters social behaviors and the hippocampal ultrastructure in adult mouse offspring.

We recently reported that exposure to triclosan (TCS), a broad-spectrum antibacterial agent, affects social behaviors in adult mice, however, the long-lasting effects of TCS exposure during early life on social behaviors are still elusive. The present study aimed to investigate the long-lasting impacts of adding TCS to the maternal drinking water during lactation on the social behaviors of adult mouse offspring and to explore the potential mechanism underlying these effects. The behavioral results showed that TCS exposure decreased body weight, increased depression-like behavior and decreased social dominance in both male and female offspring, as well as increased anxiety-like behavior and bedding preference in female offspring. In addition, enzyme-linked immunosorbent assay (ELISA) indicated that TCS exposure increased peripheral proinflammatory cytokine levels, altered serum oxytocin (OT) levels, and downregulated the expression of postsynaptic density protein 95 (PSD-95) in the hippocampus. Morphological analysis by transmission electron microscopy (TEM) demonstrated that exposure to TCS induced morphological changes to synapses and neurons in the hippocampus of offspring. These findings suggested that TCS exposure during lactation contributed to abnormal social behaviors accompanied by increased peripheral inflammation and altered hippocampal neuroplasticity, which provides a deeper understanding of the effects of TCS exposure during early life on brain function and behavioral phenotypes.

Polystyrene nanofibers as an effective sorbent for the adsorption of clonazepam: kinetic and thermodynamic studies.

Polystyrene (PS) electrospun nanofibers were prepared via electrospinning for the adsorption of clonazepam from aqueous solution. The adsorption conditions such as adsorption time, solution pH and the amount of adsorbent were optimized. The adsorption kinetics and thermodynamic properties of clonazepam on PS nanofibers were studied under optimized conditions. The pseudo-second-order kinetic model can fit well the adsorption process of clonazepam on polystyrene nanofibers, indicating that the diffusion process in the fiber is the rate-limiting step of the adsorption process. The adsorption equilibrium data are in accordance with the Freundlich isotherm model, and the maximum adsorption capacity is 3.2 mg g-1. Thermodynamic studies revealed that the adsorption process is endothermic and spontaneous in nature. It was suggested that PS electrospun nanofibers have good potential for the separation and purification of clonazepam from a water-soluble matrix as a novel effective adsorbent material.

Glutamine as a Potential Noninvasive Biomarker for Human Embryo Selection.

To determine whether glutamine consumption is associated with embryo quality and aneuploidy, a retrospective study was conducted in an in vitro fertilization center. Spent embryo culture media from patients undergoing assisted reproduction treatment and preimplantation genetic testing (PGT) were obtained on day 3 of in vitro culture. Embryo quality was assessed for cell number and fragmentation rate. PGT for aneuploidy was performed using whole genome amplification and DNA sequencing. Glutamine levels in spent embryo culture media were analyzed by gas chromatography-mass spectrometry. The results demonstrated that glutamine was a primary contributor to the classification of the good-quality and poor-quality embryos based on the orthogonal partial least-squares discriminant analysis model. Glutamine consumption in the poor-quality embryos was significantly higher than that in the good-quality embryos (P < 0.05). A significant increase in glutamine consumption was observed from aneuploid embryos compared with that from euploid embryos (P < 0.01). The Pearson correlation coefficients between embryo quality and glutamine consumption, and between aneuploidy and glutamine consumption, were 0.430 and 0.757, respectively. The area under the ROC curve was 0.938 (95% CI: 0.902-0.975) for identifying aneuploidy. Animal experiments demonstrate that increased glutamine consumption may be a compensatory mechanism to mitigate oxidative stress. Our data suggest that glutamine consumption is associated with embryo quality and aneuploidy. Glutamine may serve as a molecular indicator for embryo assessment and aneuploidy testing.

Effects of chronic triclosan exposure on social behaviors in adult mice.

Triclosan (TCS), a newly identified environmental endocrine disruptor (EED) in household products, has been reported to have toxic effects on animals and humans. The effects of TCS exposure on individual social behaviors and the potential underlying mechanisms are still unknown. This study investigated the behavioral effects of 42-day exposure to TCS (0, 50, 100 mg/kg) in drinking water using the open field test (OFT), social dominance test (SDT), social interaction test (SIT), and novel object recognition task (NOR). Using 16S rRNA sequencing analysis and transmission electron microscopy (TEM), we observed the effects of TCS exposure on the gut microbiota and ultrastructure of hippocampal neurons and synapses. Behavioral results showed that chronic TCS exposure reduced the social dominance of male and female mice. TCS exposure also reduced social interaction in male mice and impaired memory formation in female mice. Analysis of the gut microbiota showed that TCS exposure increased the relative abundance of the Proteobacteria and Actinobacteria phyla in female mice. Ultrastructural analysis revealed that TCS exposure induced ultrastructural damage to hippocampal neurons and synapses. These findings suggest that TCS exposure may affect social behaviors, which may be caused by altered gut microbiota and impaired plasticity of hippocampal neurons and synapses.

An HPLC-MS/MS Method Using a Multitoxin Clean up Column for Analysis of Seven Mycotoxins in Aquafeeds.

BACKGROUND: In Guangdong Province of China, the climate is very wet, so there are many different fungi living in aquatic feeds, which produce mycotoxins. These compounds contaminate agricultural products worldwide and present a great threat to human health. It is necessary to determine their contamination level in aquatic feeds. OBJECTIVE: A high performance liquid chromatography (HPLC) tandem mass spectrometry (MS/MS) method was developed for the quantitative analysis of aflatoxin B1, aflatoxin M1, T-2 toxin, HT-2 toxin, deoxynivalenol, ochratoxin, and zearalenone in fish and shrimp feed. METHODS: Samples were extracted with acetonitrile-water (3+1, v/v), and degreased with acetonitrile-saturated hexane. The extract was cleaned up with a multitoxin column. The target compounds were separated on a C18 chromatographic column and analyzed simultaneously by electrospray ionization mass spectrometry in both positive and negative ion mode. Detected compounds were quantified using the matrix-matched external standard method. RESULTS: Under the optimized conditions, good linearities for the analytes in the corresponding concentration range were obtained, with correlation coefficients (r2) higher than 0.9948. LODs ranged from 1.83 to 12.63 µg/kg, and LOQs ranged from 5.49 to 37.89 µg/kg. Average recoveries for the target mycotoxins at three spiked levels ranged from 80.5 to 116.5% with RSD ranging from 2.4 to 10.4%. Twenty-three real aquafeed samples were determined by this method, and seven kinds of toxins were detected. CONCLUSION: The results show that the developed method can be successfully applied for the simultaneous determination of mycotoxins in aquatic feeds. HIGHLIGHTS: Multitoxin purification columns proved to be a powerful technique for determining seven mycotoxins simultaneously. This method ensured simple sample pretreatment and less operation time. The established method was successfully applied to the analysis of seven mycotoxins species in aquatic feeds.

Effects of low-concentration glyphosate and aminomethyl phosphonic acid on zebrafish embryo development.

Glyphosate (GLY) is the most widely used broad-spectrum, non-selective herbicide in the world, whose main degradation product is aminomethyl phosphonic acid (AMPA). Because of long-term and large-scale use, residual GLY and AMPA in the environment pose great environmental and human health threats. The purpose of this study is to evaluate the effects and mechanism of residual low-concentrations of GLY and AMPA in the environment on the development of zebrafish embryos. Zebrafish embryos were exposed to 0, 1, 10, 100, and 700 ng·mL-1 GLY and AMPA for 72 h (from 2 to 74 h post-fertilization). With increasing exposure dose, heart rates of both embryos and larvae showed a rising trend and obvious arrhythmia appeared. Defects in cardiac development and function of zebrafish juveniles may be related to altered transcription levels of cardiac development genes (TBX5, NKX2.5, BMP4) and apoptosis genes (Bcl-2, Bax). In addition, pericardial edema and bone deformation of zebrafish embryos may be caused by inhibition of Na+/K+-ATPase and Ca2+-ATPase after exposure to GLY and AMPA. The present results demonstrated that at typical environmental residual concentrations of GLY and AMPA had similar developmental toxicity in zebrafish embryos.

Metabolomic mechanisms of short chain chlorinated paraffins toxicity in rats.

Short chain chlorinated paraffins (SCCPs) have received increased interest worldwide since they were added to the list of controlled POPs in Annex A of the Stockholm Convention in 2017. Although many toxicological studies have already shown that SCCPs are hepatotoxic, nephrotoxic, and thyrotoxic to rodents, there have been few studies to date that have characterized changes in the metabolic pathways targeted by SCCPs. In this study, a UPLC-Q-TOF-MS based plasma metabolomics approach was used to investigate the toxicity of SCCPs in rats. Liver and kidney injury occurred rapidly after high-dose SCCP exposure, and the most relevant pathways affected were energy metabolism, amino acid metabolism, glycerophospholipid metabolism, nucleotide metabolism, and vitamin B metabolism. Exposure to SCCPs inhibited the tricarboxylic acid cycle and accelerated degradation. Fluctuating levels of phospholipids and nucleotides may have contributed to the neurotoxicity of SCCPs. In addition, the down regulation of folic acid induced by SCCPs may have led to malformations during the early development of laboratory animals. These results suggested that high exposure levels of SCCPs may have serious health risks and more research is needed to assess the health status of relevant occupational groups.

Determination of gamithromycin residues in eggs, milk and edible tissue of food-producing animals by solid phase extraction combined with ultrahigh-performance liquid chromatography-tandem mass spectrometry.

A high throughput method was developed and validated for the quantitation of gamithromycin residues in eggs, milk and animal tissues (leg muscle, kidney, liver and fat) of different species and genera. This was undertaken using ultrahigh-performance liquid chromatography-tandem mass spectrometry (UHPLC-MS/MS). The samples were extracted with acetonitrile and purified using an Oasis MCX solid phase extraction cartridge. Subsequently, a C18 column was used for chromatographic separation using acetonitrile and 0.1% formic acid as the mobile phase. LC-MS/MS in positive ESI and multiple reaction monitoring mode with gamithromycin-D4 as the internal standard was used for detection and quantification of gamithromycin. The method was successfully calibrated in the range of 1.0-200 µg/kg. The limit of detection (LOD) and limit of quantification (LOQ) for gamithromycin was 0.30-0.40 µg/kg and 0.80 - 1.0 µg/kg, respectively. The average recoveries of the analyte fortified at three levels ranged from 84.2% to 115.9%, with a relative standard deviation <10%. The proposed method has been successfully used to monitor real samples, and shown to be sensitive, rapid, and convenient. Hence, this method could be used for regulatory purposes to screen for the presence of gamithromycin residues in eggs, milk and target tissues.

Determination of 12 insect growth regulator residues in foods of different matrixes by modified QuEChERS and UPLC-MS/MS.

An analytical method was developed and validated for the simultaneous determination of 12 insect growth regulators (IGRs) (buprofezin, cyantraniliprole, flubendiamide, flonicamid, tolfenpyrad, chlorantraniliprole, RH-5849, methoxyfenozide, chromafenozide, tebufenozide, pyriproxyfen and fenoxycarb) in foods collected from different matrixes by modified QuEChERS and ultraperformance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS). The samples were ultrasonically extracted with acetonitrile containing 0.5% formic acid, and different QuEChERS purification conditions were optimized for different matrixes (vegetable oil, fruit and tea). 12 IGRs were separated on a Plus C18 column, and detected by MS/MS under multiple reaction monitoring (MRM) mode. The developed method was validated in terms of linearity, matrix effect, accuracy and precision. Acceptable recoveries of IGRs in three different substrates (vegetable oil, tea and fruit) at three spiked levels were in the range of 65.47-95.17%, 80.55-110.15%, and 62.02-96.50%, respectively, with RSDs less than 11.58%. The method showed a good linearity (R 2 ≥ 0.9994) for all analytes in the range of 0.2-200 µg L-1. The LODs (S/N = 3) and LOQs (S/N = 10) of the method were 0.04-0.40 µg kg-1, and 0.13-1.24 µg kg-1, respectively. Owing to the advantages of simple operation, high accuracy and sensitivity, this method is suitable for the rapid and simultaneous detection of 12 IGRs in vegetable oil, tea and fruit.

Long-lasting effects of postweaning sodium butyrate exposure on social behaviors in adult mice.

BACKGROUND: The function of gut microbiota as its role in normal physiology and involvement in brain function has gained a great deal of attention. The potential long-lasting effects of postweaning sodium butyrate (SB) exposure on social behaviors are still unknown; however it acts as one of the metabolites of gut microbiota. METHODS: Male mice (24-day old) were exposed to SB through drinking water for 21 continuous days. A series of behavioral tests, mainly including bedding preference test (BP), sexual preference test (SP), social interaction test (SI), tube dominance test (SDT), forced swimming test (FST), open field test (OFT), novel object recognition task (NOR) were conducted at different time after 21-d SB exposure. Serum Trimethylamine oxide (TMAO) levels were investigated to gain insight into a potential mechanism. RESULTS: Behavioral results indicated that postweaning SB exposure significantly decreased the social dominance status of low-ranked mice and decreased the sexual preference without affecting social interaction. SB exposure also exerted transient anxiolytic-like effects, while having induced a long-lasting depression-like effect without effects on memory formation. Postweaning SB exposure increased serum TMAO levels in mice, especially in lower-ranked mice, but decreased in higher-ranked mice. LIMITATIONS: Lack of understanding of the underlying mechanism. CONCLUSIONS: These findings provide direct evidence, for the first time, that postweaning SB exposure produces long-term effects on social behaviors in adult mice, mainly referring to sexual orientation, social dominance, and depression-like behaviors, which may be related to the serum TMAO levels, highlighting the long-lasting potential effects of gut-brain interaction on social behaviors.

Simultaneous determination of 11 antiseptic ingredients in surface water based on polypyrrole decorated magnetic nanoparticles.

With the emergence and spread of coronavirus COVID-19, the use of personal cleansing, medical and household disinfectant products have increased significantly. In this work, a new magnetic solid-phase extraction (MSPE) method for the determination of 11 antiseptic ingredients in surface water by high performance liquid chromatography-mass spectrometry (HPLC-MS/MS) for 6 months based on Fe3O4@PPy magnetic nanoparticles (MNPs) was established. The MSPE method possessed the advantages of simple processing, little time consumption and less organic solvent consumption, and the MNPs could be reused several times. The analytical parameters influencing the extraction efficiency, such as sample pH, amount of MNPs and extraction time, were optimized in detail. It was indicated that the method had satisfactory linearities in the range of 0.50 to 1000.0 µg L-1 with the correlation coefficients (r) higher than 0.9996. Additionally, satisfactory spiked recoveries were achieved in the range of 80.21-107.33% with relative standard deviations (RSDs) from 1.98% to 8.05%. The limits of detection (LODs) and limits of quantitation (LOQs) were in the range of 0.20 to 2.0 µg L-1 and 0.50 to 5.0 µg L-1. Therefore, the developed MSPE-HPLC-MS/MS method has high selectivity and stability, and satisfactory quantitative capability for the antiseptic ingredients in surface water. Furthermore, this method can provide relevant technical support for the development of surface water standards.

An untargeted and pseudotargeted metabolomic combination approach to identify differential markers to distinguish live from dead pork meat by liquid chromatography-mass spectrometry.

An untargeted and pseudotargeted metabolomic combination approach was developed to identify reliable and stable differential markers which can distinguish between pork meat from live pigs conventionally butchered and pork meat from dead pigs butchered immediately after death from diseases or other abnormalities. In this study, 24 differential metabolites of interest were screened by the UHPLC-Triple-TOF-MS-based untargeted metabolomic method, and 14 differential markers were detected by the UHPLC-QTRAP-MS-based pseudotargeted metabolomic method after performing statistical analysis to remove false-positive differential metabolites. Among the possible differential markers identified using the Metlin database and references were carnosine, l-carnitine, l-histidine, N-acetylhistidine, acetylcholine, l-acetylcarnitine and two phosphatidylcholines. The results of the principal component analysis (PCA) and the hierarchical clustering analysis (HCA) indicate that 14 differential markers could be potentially used to distinguish live and dead pork meat. This reliable and stable approach not only could detect the unknown differential markers, but also accurately quantify them.

Simultaneous Determination of Five Hormones in Milk by Automated Online Solid-Phase Extraction Coupled to High-Performance Liquid Chromatography.

BACKGROUND: Many hormones show the effects of protein assimilation and growth promotion, and they are frequently used as veterinary drugs in livestock, which has harmful effects on human health. It is necessary to determine their contamination level in animal-derived food, especially in milk. OBJECTIVE: In this study, a detailed procedure is described for an automated online solid-phase extraction (SPE)-HPLC method capable of detecting five hormones (i.e., estriol, prednisone acetate, hydrocortisone, diethylstilbestrol, and estrone) in cow milk. METHODS: The corresponding milk samples were precipitated by addition of acetonitrile and then purified as well as enriched by a polar-enhanced polymer (PEP) online SPE column. The supernatants were directly injected into the online SPE-HPLC system using methanol-water as the mobile phase mixture. RESULTS: The linearity range of the method was 0.1-25 µg/mL for prednisone acetate, hydrocortisone, and diethylstilbestrol, 0.2-25 µg/mL for estriol, and 0.5-25 µg/mL for estrone, with correlation coefficients (r) ranging from 0.9994 to 0.9996. The recovery rates determined at three concentration levels for the five compounds were in the range of 70.82-112.90%. LODs of estriol, prednisone acetate, hydrocortisone, diethylstilbestrol, and estrone were 0.023, 0.005, 0.006, 0.004, and 0.054 µg/mL, respectively. CONCLUSIONS: This automated online SPE-HPLC method was both effective and reliable in the simultaneous measurement of five hormones, and the method was successfully applied to the detection of five hormone species in milk. HIGHLIGHTS: An automated online SPE-HPLC method has been developed for the analysis of five hormones in cow milk. Online SPE proved to be a powerful technique for determining five hormones simultaneously. This method ensured simple sample pretreatment and less operation time. The established method was successfully applied to the analysis of five hormone species in milk.

Determination of higenamine in multi-matrix by gas chromatography-mass spectrometry combined with derivatization technology.

Higenamine (HG), a cardioactive component of some foods and medicines, has been listed in the doping category by the International Olympic Committee, which may lead to misuse by athletes. We report the development of a gas chromatography-mass spectrometry (GC-MS) method for determination of HG in various matrix samples (biological samples, different forms of Chinese patent medicine, Chinese herbal medicine) based on acylation derivatization of HG by heptafluorobutyric anhydride. Under optimal conditions, the linearity of HG in the range of 5-200 ng mL-1 was acceptable (R2 > 0.999), and the limit of detection (LOD) and limit of quantitation (LOQ) for HG was 1.52 ng mL-1 and 5 ng mL-1, respectively. Low, medium, and high concentrations (25, 100 and 160 ng mL-1) of HG were added to plasma, urine, oral liquid, capsule, watered bolus, honeyed bolus and Chinese herbal medicine samples, with recovery ranging from 82.70 to 109.80%, intra-day and inter-day precisions were both less than 3.39%. The results indicated that the method had sufficient sensitivity for analysis of biological samples, and Chinese patent and herbal medicine.

Analysis of four antidepressants in plasma and urine by gas chromatography-mass spectrometry combined with sensitive and selective derivatization.

A sensitive and selective method was developed for simultaneous determination of four antidepressants (ATDs) in plasma and urine samples by gas chromatography- mass spectrometry (GC-MS) based on an N-nitrosation reaction. In this study, fluoxetine (Flu), nortriptyline (Nor), maprotiline (Map), and paroxetine (Paro) were first derivatized with sodium nitrite to appropriate N-nitrosamines under acidic condition, then the derivatives were easier to detect by GC-MS. The derivatization conditions including the amount of hydrochloric acid, the amount of sodium nitrite, reaction temperature, reaction time and the extraction reagents were optimized. Under the optimal conditions, the limit of detections (LODs) and limit of quantitations (LOQs) were in the range of 0.04-1.38 µg L-1 and 0.14-4.62 µg L-1, respectively. Low, medium, and high concentrations of antidepressants were added in plasma and urine samples, spiked recovery ranged from 85.88%-110.34% for plasma and 80.64%-113.07% for urine, respectively. The derivatization reaction was very quickly, only 5 min was needed for the reaction process, in addition, the proposed method exhibited superior sensitivity and selectivity, it showed sufficient advantages for determination of Flu, Nor, Map, and Paro in plasma and urine of patients.