Determination of six volatile fatty acids in human serum, urine and faeces by low temperature derivatisation combined with HPLC-MS/MS.

A stable isotope dilution-liquid chromatography tandem mass spectrometry method based on a low-temperature derivatization strategy with 3-nitrophenylhydrazine (3-NPH) was developed for the determination of six volatile fatty acids (VFAs) in serum, urine, and feces. Ice acetonitrile was used to precipitate proteins and extract the target analytes. The extract was derivatized with 3-NPH methanol solution at 4 °C. BEH C8 (1.7 µm, 2.1 × 100 mm) column was used for chromatographic separation, and acetonitrile-water (both containing 0.01 % formic acid) were used as the mobile phase with a gradient elution of 10 min. Electrospray ionization source (ESI) in negative ion multiple reaction monitoring (MRM) mode were used for analyte detection. The regression coefficients R2 of the calibration curves for the six VFAs were in the range of 0.9963-0.9994, and the LOQs were in the range of 0.02-0.5 µg mL-1, with the recoveries in the range of 85.3-104.3 %, and the intra- and inter-day precision in the range of 1.8-9.1 %. The method is simple, accurate and reliable, and has been applied in the sensitive determination of VFAs in complex biological samples.

Development and application of a sensitive liquid chromatography-tandem mass spectrometry method for the quantitative analysis of 11 free fatty acids in human serum using a derivatisation strategy.

A stable isotope dilution-liquid chromatography-tandem mass spectrometry method based on a derivatisation strategy involving an N,N'-carbonylimidazole solution (CDI) with 4-(dimethylamino)-benzenemethanamine was developed for the determination of 11 free fatty acids (FFAs) in human blood samples. Serum samples were subjected to liquid‒liquid extraction and centrifuged, and the supernatant was collected for a two-step derivatisation reaction with a CDI and 4-(dimethylamino)-aniline acetonitrile solution. The derivatised solution was separated on a ACQUITY UPLC HSS T3 column (2.1 × 50 mm, 1.8 µm) column with a mobile phase consisting of water-acetonitrile in gradient elution and then detected by tandem mass spectrometry using electrospray ionisation (ESI) and multiple reaction monitoring (MRM) in positive ion mode and quantified using the isotope internal standard method. The effects of the derivatisation reaction time, temperature and concentration of derivatisation reagents on the response values of the analytes were investigated. The optimal conditions were as follows: 1.0 mg mL-1 CDI acetonitrile solution at 25 °C for 25 min, followed by a reaction with a 1.0 mg mL-1 4-(dimethylamino)-benzenemethanamine acetonitrile solution at 70 °C for 30 min. Under the optimal conditions, the limits of detection (LODs) of the 11 FFAs were in the range of 3.0-14.0 ng mL-1; the limits of quantification (LOQs) were in the range of 8.0-45.0 ng mL-1; and the mean recoveries ranged from 83.4 to 112.8%, with intraday and interday precisions ranging from 0.7 to 9.1% and 3.7-9.5%, respectively. The experimental method is simple in terms of the pretreatment operation, accurate and reliable, and can be applied to the sensitive determination of FFAs in human blood samples.

Photoregulatory protein kinases fine-tune plant photomorphogenesis by directing a bifunctional phospho-code on HY5 in Arabidopsis.

Photomorphogenesis is a light-dependent plant growth and development program. As the core regulator of photomorphogenesis, ELONGATED HYPOCOTYL 5 (HY5) is affected by dynamic changes in its transcriptional activity and protein stability; however, little is known about the mediators of these processes. Here, we identified PHOTOREGULATORY PROTEIN KINASE 1 (PPK1), which interacts with and phosphorylates HY5 in Arabidopsis, as one such mediator. The phosphorylation of HY5 by PPK1 is essential to establish high-affinity binding with B-BOX PROTEIN 24 (BBX24) and CONSTITUTIVE PHOTOMORPHOGENIC 1 (COP1), which inhibit the transcriptional activity and promote the degradation of HY5, respectively. As such, PPKs regulate not only the binding of HY5 to its target genes under light conditions but also HY5 degradation when plants are transferred from light to dark. Our data identify a PPK-mediated phospho-code on HY5 that integrates the molecular mechanisms underlying the regulation of HY5 to precisely control plant photomorphogenesis.

The Receptor Kinases DRUS1 and DRUS2 Behave Distinctly in Osmotic Stress Tolerance by Modulating the Root System Architecture via Auxin Signaling.

Receptor kinases DRUS1 (Dwarf and Runtish Spikelet1) and DRUS2 are orthologues of the renowned Arabidopsis thaliana gene FERONIA, which play redundant roles in rice growth and development. Whether the two duplicated genes perform distinct functions in response to environmental stress is largely unknown. Here, we found that osmotic stress (OS) and ABA increased DRUS1 expression while decreasing DRUS2. When subjected to osmotic stress, the increased DRUS1 in drus2 mutants suppresses the OsIAA repressors, resulting in a robust root system with an increased number of adventitious and lateral roots as well as elongated primary, adventitious, and lateral roots, conferring OS tolerance. In contrast, the decreased DRUS2 in drus1-1 mutants are not sufficient to suppress OsIAA repressors, leading to a feeble root system with fewer adventitious and lateral roots and hindering seminal root growth, rendering OS intolerance. All these findings offer valuable insights into the biological significance of the duplication of two homologous genes in rice, wherein, if one is impaired, the other one is able to continue auxin-signaling-mediated root growth and development to favor resilience to environmental stress, such as water shortage.

Rapid authentication of characteristic milk powders by recombinase polymerase amplification assays.

The authentication of dairy species has great significance for food safety. This study focused on a more rapid method for identifying major dairy species, and specific recombinase polymerase amplification (RPA)-based assays for cattle, goat, sheep, camel and donkey were developed. Through the developed RPA-based assays, goats and sheep could be simultaneously identified and bovine families could be differentiated. The performances of the RPA assays were validated using 37 milk powder samples, of which 16.2% (6/37) were suspected of being adulterated and 24.3% (9/37) were potentially at risk of being wrongly identified as adulteration. The effectiveness of the developed assays for crude DNA detection was also validated by a rapid nucleic acid extraction kit, and results showed that the presence of large amounts of protein and fat did not affect the qualitative results. Therefore, these assays could combine with the rapid nucleic acids extraction methods for being used in field detection.

[Development of a multi-residue detection method for 27 typical pharmaceuticals and personal-care products in plants and analysis of their migration patterns in sprouts].

An analytical method based on ultra-performance liquid chromatography-tandem mass spectrometry was developed for the simultaneous determination of 27 pharmaceutical and personal-care product (PPCP) residues in plants. The enrichment and cleanup of PPCPs in plants were achieved using an HLB extraction column, and the separation was performed on a BEH C18 column (100 mm×2.1 mm, 1.7 µm) with 0.1% formic acid water-acetonitrile as the mobile phase via gradient elution. PPCPs were detected with electrospray ionization mass spectrometry in positive-ion multiple-reaction monitoring (MRM) mode. The limits of detection and quantification of the 27 PPCPs in plants were 0.01-0.30 µg/kg and 0.03-0.98 µg/kg, respectively. Good linearities were observed with coefficients of determination (r2) >0.99. The spiked recoveries were between 80.8% and 122.3% with relative standard deviations (RSDs) between 1.0% and 9.9%. The method was subsequently used to study sprouts grown in different concentrations of PPCPs. A total of 10 PPCPs were detected in sprouts grown in medium with a low concentration PPCPs, 13 PPCPs were detected in sprouts grown in medium with a moderate concentration of PPCPs, and 19 PPCPs were detected in sprouts grown in medium with a high concentration of PPCPs. These results showed that plants grown in water bodies contaminated with PPCPs or irrigated with water contaminated with PPCPs absorbed and accumulated these substances and that the amount and type of PPCPs absorbed by plants were closely related to the levels of PPCPs in the external environment. Analysis of the contents of PPCPs in different plant tissues revealed a general distribution of root>stem>leaf. Haemosibutramine showed a tissue distribution of leaf>stem>root, while glibenclamide showed a distribution of root>leaf>stem; these results revealed differences in the distribution of PPCPs in plants. Calculation of the transfer factor (TF) of the PPCPs in plants demonstrated significant differences in the transferability of different PPCPs, with TF=2.34 for haemosibutramine and TF=1.25 for chlorosibutramine. The results showed that among the drugs that migrated in plants, haemonosibutramine and chlorosibutramine had the strongest migration ability in sprouts, followed by nicardipine and chlorpheniramine maleate, and amantadine, N-monodesmethyl sibutramine, carbamazepine and flumequine had the weakest migration ability. Once absorbed, these compounds were transferred to the stems and/or leaves, where they accumulate and cause potential harm by contaminating other plant organs. Therefore, PPCPs such as homosibutramine and chlorosibutramine, which easily migrate in plants, should be given extra attention in future studies. The method is simple in pre-treatment, sensitive and accurate, and can be widely applied to the detection of PPCP residues in plant samples.

Quantification of orelabrutinib in human plasma and cerebrospinal fluid by liquid chromatography tandem mass spectrometry.

A sensitive and simple method was developed to determine orelabrutinib in human plasma and cerebrospinal fluid by liquid chromatography tandem mass spectrometry (LC-MS/MS). The samples were prepared by simple protein precipitation with by 0.1% formic acid acetonitrile solution and efficient separations were performed on the Thermo Hypersll GOLD C18 column (2.1 mm × 150 mm, 5 µm) under a gradient program in a total run time of 9 min. The orelabrutinib was detected by electrospray ionization in positive ion mode with selective reaction monitoring (SRM) and mass spectrometric conditions were optimized in order to increase selectivity and sensitivity. The developed method was validated in terms of its accuracy, precision, selectivity, linearity, recovery, matrix effect, stability, and limits of quantification (LOQ). The lower limit of quantification is 0.50 ng/mL, the intraday and interday precision RSD are both less than 15%, and the recovery rate is 85.7%-92.9%. Finally, the method was successfully applied for the quantitation of orelabrutinib in human plasma and cerebrospinal fluid of clinical patients treated with orelabrutinib.

Rapid detection of duck ingredient in adulterated foods by isothermal recombinase polymerase amplification assays.

Duck is often used in meat fraud as a substitute for more expensive meats. Rapid detection of duck ingredient in meat products is of great significance for combating meat fraud and safeguarding the interests of consumers. Therefore, we aim to develop duck-specific recombinase polymerase amplification (RPA)-based assays for the rapid detection of duck ingredient in animal-derived foods. Using Cytb gene as target, the real-time RPA and RPA combined with lateral flow strips (LFS RPA) were developed successfully for the rapid detection of ducks in 20 min at 39 °C and 40 °C, respectively. The assays did not show cross-reactions with 6 other livestock and poultry. The developed RPA assays could detect 10 pg duck genomic DNA per reaction and 0.1 % (w/w) duck ingredient in duck and mutton mixed powder within 30 min, including a rapid nucleic acid extraction. Furthermore, duck ingredient could be detected in 30 different actual foods including heat-processed meats and blood products. Therefore, duck-specific real-time RPA and LFS RPA assays were successfully developed with good specificity and sensitivity, which could enable rapid detection of duck ingredient in the field and provide technical support for combating the meat fraud.

Screening and quantification of 146 veterinary drug residues in beef and chicken using QuEChERS combined with high performance liquid chromatography-quadrupole orbitrap mass spectrometry.

This work aimed to develop an integrated high-throughput screening and quantification for multi-class veterinary drug residues by HPLC-Q-Orbitrap mass spectrometry. A qualitative screening mass database of 171 veterinary drugs was created using full scanning mode, which improved the screening accuracy and scope. Beef and chicken samples were chosen to validate the quantification method at three spiked concentration levels. The quantification method of 146 veterinary drug residues was developed. After enzymatic hydrolysis, beef and chicken samples were treated using optimized QuEChERS. The calibration curves showed good linearities with correlation coefficients of 0.9921-0.9994. The recovery rates were within 52.1-138.2 % with relative standard deviations 0.4-17.7 %. The limits of detection and limits of quantification were in the range of 0.15-3.03 µg/kg and 0.5-10 µg/kg, respectively. The proposed method was demonstrated to be reliable for the simultaneous analysis of multi-class veterinary drugs. It is of significance to expand the screening scope and quantitative analysis efficiency.

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).

Rapid determination of 103 common veterinary drug residues in milk and dairy products by ultra performance liquid chromatography tandem mass spectrometry.

A multi-residue method has been developed for the identification and quantification of 103 common veterinary drug residues in milk and dairy Products. This method was based on QuEChERS with dispersive solid-phase where C18 sorbent and anhydrous sodium sulfate were used to sample purification. After evaporation and reconstitution, the samples were analyzed by ultra-performance liquid chromatography-tandem mass spectrometry. The mean recovery results were all higher than 60% except ampicillin, pipemidic acid, enoxacin, and estriol, and the relative standard deviation was <20.0%. The limit of quantification ranged between 0.1 and 5 µg/kg for milk and between 0.5 and 25 µg/kg for milk powder. It was successfully used to detect residues of veterinary drug in real samples. This study proposes a simple and fast analytical method for monitoring multi-class veterinary drug residues to ensure food safety.

Determination of Vancomycin and Norvancomycin Residues in Milk by Automated Online Solid-Phase Extraction Combined With Liquid Chromatography-High Resolution Mass Spectrometry.

BACKGROUND: Vancomycin and norvancomycin, as potent antibacterial retention drugs, were used illegally on animals bred for food, which directly affected the quality and safety of animal-derived food, and even harmed human health. OBJECTIVE: A fast analysis method, which was adopted to detect residues of vancomycin and norvancomycin in milk, was implemented on a chromatographic system containing online solid-phase extraction (SPE) device that combined with high-resolution mass spectrometer (HRMS). METHOD: First, the analytes were added to the blank milk sample were extracted with water [containing 0.1% trifluoroacetic acid (TFA)]-acetonitrile (ACN) (8:2, v/v), and then were purified and enriched on a C18-XL column, whereafter eluted from the purification column onto the analytical column (Shiseido Capcell Pak ADME column) for chromatographic separation prior to hybrid quadrupole-Orbitrap (Q-Orbitrap) detection. RESULTS: The results showed that the limit of detection (LOD) for each analyte and the limit of quantitation (LOQ) were 0.15 and 0.5 µg/kg, respectively. The correlation coefficient(s) of vancomycin and norvancomycin ranged from 0 to 200 ng/mL were greater than 0.9983. CONCLUSIONS: These validations reflected that it was suitable for the established method to rapidly analyze vancomycin and norvancomycin residues in milk. HIGHLIGHTS: The method for detecting vancomycin and norvancomycin residues in milk by online SPE combined with LC-HRMS. Online SPE technology realized automation, and the application of HRMS greatly improved the reliability of qualitative and quantitative analyses. The developed method is fast, simple, and reliable; each methodological index can meet requirements of trace analyses of vancomycin and norvancomycin in milk.

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.

Discrimination of meat from fur-producing and food-providing animals using mass spectrometry-based proteomics.

Non-edible meat from fur-producing animals entering into meat consumption chain could pose a serious threat to public health. For the purpose of risk prevention and control of meat safety, in this study, marker peptides for discriminating non-edible meat of fur-producing animals (including fox, silver fox, blue fox, raccoon dog, ussuri raccoon dog, mink and American mink) from meat of food-providing animals (including pig, cattle, sheep and donkey) were explored by shot-gun proteomics and verified by target approach. Two mass spectrometry platforms combined with bioinformatic and chemometric tools were integratedly emloyed for method development. Meat samples were first subjected to in-solution protein digestion and the subsequently tryptic peptides were profiled and quantitated by ultra-high pressure liquid chromatography-quadrupole time-of-flight mass spectrometry (UHPLC-Q/TOF MS) with sequential windowed acquisition of all theoretical fragment ion mass spectra (SWATH-MS) mode. Candidate marker peptides screened by chemometric tools were further filtered for their biological specificity and detectability through bioinformatics analysis as well as multiple reaction monitoring (MRM) verification with UHPLC-triple quadrupole mass spectrometry (UHPLC-QQQ MS). As a result, 9 peptides, out of 104 candidates, were selected as markers for discriminating analysis, of which DQTLQEELAR was validated as primary indicator of non-edible meat from the concerned fur-producing animals. An MRM method based on the developed marker peptides for routine use was finally proposed for risk alarming of non-edible meat from fur-producing animals in food safety control.

Rapid and simultaneous determination of ten anti-tuberculosis drugs in human plasma by UPLC-MS/MS with applications in therapeutic drug monitoring.

Tuberculosis remains a global challenge, particularly with a growing number of resistant cases, which may become an obstacle to eliminating this disease. Standardized short-course therapy composed of first-line anti-tuberculosis drugs isoniazid (INH), rifampicin (RIF), ethambutol (EMB), and pyrazinamide (PZA) is playing vital roles for curbing the rapid spread of tuberculosis. However, some patients have poor responses to standardized short-course therapy. As the number of drug-resistant tuberculosis increase, some other anti-tuberculous drugs are needed to achieve better treatment outcomes. In this study, we established a UPLC-MS/MS method for simultaneous detection of ten anti-tuberculosis drugs in human plasma including INH, EMB, PZA, RIF, rifampin, rifapentine as well as four second-line antituberculosis drugs, i.e. ethionamide, protionamide, thiosemicarbazone and clofazimine. This study contains almost all the commonly used anti-tuberculosis drugs. The plasma samples were treated with acetonitrile to precipitate proteins, and doped with the isotope internal standard. A Shiseido CAPCELL RAK-ADME (2.1 mm × 50 mm, 3 µm) column was used for chromatographic separation, and acetonitrile-water (containing 0.1% formic acid) was the mobile phase. The separation used gradient elution with a flow rate of 0.4 mL/min. The column temperature was 40 °C, and the sample volume was 1 µL. The electrospray ionization source (ESI) and the positive ion multiple reaction monitoring (MRM) mode were used for the detection. The analysis time was as short as 7 min. The results show a good linear relationship under optimized conditions in the range of 5.00-7.50 × 103, 1.00-1.50 × 103, 5.00-5.00 × 104, 5.00-7.50 × 103, 1.00-3.00 × 103, 1.00 × 101-1.00 × 104, 1.00-3.00 × 103, 1.00-3.00 × 103, 2.00-4.00 × 103, and 1.00 × 10-1-2.00 × 102 ng/mL for INH, EMB PZA, RIF, rifabutin, rifapentine, ethionamide, protionamide, thiosemicarbazone, and clofazimine, respectively, with a linear correlation coefficient of R > 0.99. Finally, 34 patients with pulmonary TB were tested for therapeutic drug monitoring. The results showed that the presented method have significant advances in sensitivity, separation efficiency and simplicity.

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.

[Determination of 15 amide herbicides in rice using monolith column for on-line solid-phase extraction coupled with liquid chromatography-tandem mass spectrometry].

A method based on on-line solid-phase extraction (SPE) coupled with high performance liquid chromatography-tandem mass spectrometry was developed for the simultaneous determination of 15 amide herbicides in rice. A poly(butyl methacrylate-co-ethylene dimethacrylate) monolithic column was utilized as the solid-phase column. The sample was extracted with acetonitrile, cleaned up with the monolithic column in online mode. Subsequently, the analyte was eluted from the extraction column onto the analytical column (Hypersil GOLD column) by 0.5%(v/v) formic acid aqueous solution-acetonitrile in gradient elution mode. Electrospray ionization mass spectrometry was performed in the positive mode and multiple reaction monitoring (MRM) mode. Under the optimized conditions, good linearities were obtained with correlation coefficients of more than 0.998. The limits of detection (LODs) and limits of quantification (LOQs) were in the range 0.20-2.0 µg/kg and 0.50-5.0 µg/kg, respectively. The average recoveries were in the range 75.5% to 121.3% at spiked levels of 2.0, 5.0, 10.0, and 50.0 µg/kg for 14 amide herbicides and 5.0, 10.0, 50.0, and 100.0 µg/kg for propanil. The relative standard deviations ranged from 2.89% to 12.38%. The proposed method is simple, rapid, and highly sensitive, and it can be applied to the simultaneous identification and quantification of the 15 amide herbicides in rice.

Studies on the metabolism and degradation of vancomycin in simulated in vitro and aquatic environment by UHPLC-Triple-TOF-MS/MS.

Vancomycin is one of the most commonly used glycopeptide antiobiotics, and as such is an important emerging environmental contaminant. Pharmaceuticals and personal care products (PPCPs), such as antibiotics, are problematic since wastewater treatment processes are not completely effective at removing these chemical compounds. Since wastewater treatment processes are not completely effective, vancomycin occurs in surface water. Vancomycin and its metabolites in vivo and degradation products in aquatic environment may lead to undesirable ecological effects that threaten the environment or cause undesirable reactions that affect human health. We aimed to study vancomycin metabolism in vitro and its natural degradation in aquatic environment, as well as explore for related metabolites and degradation products. Accordingly, we established four systems, using a constant temperature oscillator at 37 °C for 10 days for vancomycin in activated rat liver microsomes (experimental system), inactivated rat liver microsomes (control system), phosphate buffer saline (PBS system) and pure water (pure water system), as well as an additional system of activated rat liver microsomes without vancomycin (blank system). The metabolism and degradation of vancomycin were studied using a high resolution and high sensitivity ultra-high performance liquid chromatography (UHPLC)-Triple-time of flight (TOF)-mass spectrometry (MS) method in positive ion mode. The compared result of activated rat liver microsomes system and inactivated rat liver microsomes system confirms that vancomycin is not metabolized in the liver. Vancomycin was degraded in the four non-blank incubation systems. The MetabolitePilot 2.0 software was used for screening the probable degradation products, as well as for establishing its associated degradation pathways. Eventually, four degradation products were identified and their chemical structures were deduced. The results of this study provide a foundation for evaluation of the effects of vancomycin and its degradation products on environmental safety and human health in the future.

Rapid monitoring of plant growth regulators in bean sprouts via automated on-line polymeric monolith solid-phase extraction coupled with liquid chromatography tandem mass spectrometry.

An automated on-line solid-phase extraction (SPE) following liquid chromatography tandem mass spectrometry was established for the fast determination of plant growth regulator residues in soybean sprout and mung bean sprout. The crude extracted specimens were directly purified on a poly (2-(dimethylamino) ethyl methacrylate-co-ethylene dimethacrylate) monolithic column which was well-defined as the on-line SPE adsorbent. Under the optimized conditions, the developed method gave the linear range of 0.3-50 ng/mL for gibberellin and 2,4-dichlorophenoxyacetic acid, 0.2-50 ng/mL for 4-chlorophenoxyacetic acid, and 0.5-50 ng/mL for 1-naphthaleneacetic acid (r ≥ 0.998). The detection limits (S/N = 3) ranged from 1.0 to 2.5 µg/kg and the recoveries for spiked soybean sprout samples were in the range of 75.0-93.3%. Besides, the total time for one analysis was 16 min. The reusability of the monolith was up to 600 extractions. The proposed process facilitated fully automated SPE and accurate determination in one step with rapidity, simplicity, and reliability. Graphical abstract ᅟ.