RESUMO
An integrated method combining solid-phase extraction (SPE) with ultra-performance liquid tandem mass spectrometry (UPLC-MS/MS) has been established for quantifying bacitracin (BTC), bacitracin zinc (BZ), and bacitracin methylene disalicylate (BMD) in animal feed. A pretreatment procedure that can effectively, quickly, and simultaneously extract and purify BTC, BZ, or BMD in feed was developed for the first time through the optimization of extraction and SPE conditions. After extraction with acetonitrile + methanol + 15 % ammonia solution (1:1:1, v:v:v) and dilution with EDTA solution (1.5 mmol/L, pH 7.0), a SPE procedure was carried out with C18 cartridge. Following LC-MS/MS analysis utilized a Waters Peptide BEH C18 column with a gradient elution of 0.1 % formic acid in water/acetonitrile with. This method demonstrated a strong linear correlation (R2 > 0.9980) across a 0.01-1.0 mg/L concentration span, based on a matrix-matched standard curve. Satisfactory recoveries of BTC (bacitracin A, B1, B2, and B3), BZ, and BMD in different feeds were obtained from 80.7 % to 108.4 %, with relative standard deviations below 15.7 %. Low limits of quantification ranging within 7.2-20 µg/kg were achieved for bacitracin A, B1, B2, and B3. This method provided an effective and reliable detection method to prevent the addition of BTC and different BTC formulations in feeds.
Assuntos
Ração Animal , Bacitracina , Limite de Detecção , Espectrometria de Massas em Tandem , Bacitracina/análise , Espectrometria de Massas em Tandem/métodos , Ração Animal/análise , Cromatografia Líquida de Alta Pressão/métodos , Modelos Lineares , Reprodutibilidade dos Testes , Extração em Fase Sólida/métodos , Salicilatos/análise , Animais , Resíduos de Drogas/análiseRESUMO
A sensitive and robust multiclass analytical method was established to simultaneously determine 55 antibiotics in aquatic products through liquid chromatography-tandem mass spectrometry. A simple one-step purification process was successfully developed, which combined post-acidic acetonitrile extraction directly by an enhanced matrix removal cartridge. This approach eliminated the need for solvent transition. The established method for 55 antibiotics achieved an excellent linear relationship with R2 values ≥ 0.9921 in the range of 0.05-200 µg/L. The quantitation limits ranged within 0.04-5.0 µg/kg. Satisfactory recoveries (76.2%-99.7 %) were achieved with the relative standard deviations below 13.9 %. Furthermore, the antibiotic residues in aquatic products were analyzed, and the health and antibiotic resistance risk assessments were conducted. Although the health risks of target antibiotics were acceptable, a resistance risk was observed. Therefore, monitoring antibiotic residue levels in aquatic products requires considerable attention and further research to ensure the quality of marine products and consumer safety.
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Antibacterianos , Espectrometria de Massas em Tandem , Espectrometria de Massas em Tandem/métodos , Antibacterianos/análise , Cromatografia Líquida de Alta Pressão/métodos , Medição de Risco , Poluentes Químicos da Água/análise , Poluentes Químicos da Água/isolamento & purificação , Animais , PeixesRESUMO
Triclabendazole (TCB) is widely used for prevention and treatment of parasitic infections in animals. Improper use can result in drug residues in animal tissues and cause health problems to humans through consumption. A simple and reliable analytical method for the determination of TCB and its metabolites in bovine and goat muscle using liquid chromatography-tandem mass spectrometry (LC-MS/MS) was developed and validated. Analytes were extracted using acetonitrile and purified using enhanced matrix removal cartridge. Chromatographic separation was carried out on a BEH Shield RP18 column. The analytes were detected in positive-mode electrospray ionization mass spectrometry using multiple reaction monitoring. Average recoveries of 96.1%-105.6% with coefficients of variation of 1.9%-8.4% were obtained at fortification levels of 0.5, 2.5, 25, and 50 µg/kg for TCB and 5.0, 25, 250, and 500 µg/kg for its metabolites (triclabendazole sulfoxide, triclabendazole sulfone, and keto-TCB). A good linear regression was obtained with the mixed standard solutions in the range of 0.05-20 µg/L for TCB and 0.5-200 µg/L for its metabolites. The limit of quantification and limit of detection ranged from 0.05 to 0.75 µg/kg and from 0.1 to 1.5 µg/kg, respectively. Moreover, this method was successfully applied to 33 real samples.
Assuntos
Cabras , Espectrometria de Massas em Tandem , Humanos , Animais , Bovinos , Triclabendazol/análise , Cromatografia Líquida/métodos , Espectrometria de Massas em Tandem/métodos , Músculos , Cromatografia Líquida de Alta Pressão/métodosRESUMO
This paper addresses the problem of decentralized safety control (DSC) of constrained interconnected nonlinear safety-critical systems under reinforcement learning strategies, where asymmetric input constraints and security constraints are considered. To begin with, improved performance functions associated with the actuator estimates for each auxiliary subsystem are constructed. Then, the decentralized control problem with security constraints and asymmetric input constraints is transformed into an equivalent decentralized control problem with asymmetric input constraints using the barrier function. This approach ensures that safety-critical systems operate and learn optimal DSC policies within their safe global domains. Then, the optimal control strategy is shown to ensure that the entire system is uniformly ultimately bounded (UUB). In addition, all signals in the closed-loop auxiliary subsystem, based on Lyapunov theory, are uniformly ultimately bounded, and the effectiveness of the designed method is verified by practical simulation.
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Raspberry is used as a medicine food homology species and its polysaccharides are worthy being investigated and developed. In the present study, a novel polysaccharide of unripe raspberry fruits (pRCP) was extracted and characterized. The results show that pRCP was an acidic heteropolysaccharide and its Mw value was 74.86 kDa with a high homogeneity. The main chain of pRCP consisted of â 3,6)-ß-Galp(1 â and â 5)-α-Araf(1â, and its side chain was composed of α-Araf(1 â linked to the C3 position of â 3,6)-ß-Galp(1 â. In addition, pRCP supplementation increased the gut microbial diversity and reduced harmful bacteria including Erysipelatoclostridium and Negativibacillus in high-fat diet (HFD)-fed mice. Treatment with pRCP also alleviated HFD-induced colonic inflammation and oxidative stress in mice. These beneficial effects can be transferred to recipient mice by faecal microbiota transplantation from pRCP-treated mice. Therefore, our study suggests that pRCP could be used as a potential prebiotics to improve intestinal health by modulating the gut microbiota.
Assuntos
Rubus , Camundongos , Animais , Rubus/química , Frutas/química , Polissacarídeos/química , Estresse Oxidativo , Inflamação/tratamento farmacológico , Dieta Hiperlipídica/efeitos adversos , Camundongos Endogâmicos C57BLRESUMO
The effect of nano-TiO2 particle size on the properties of starch-based wood adhesives was studied in this work. Our findings indicate that a smaller size of nano-TiO2 particles corresponds with a larger specific surface area and more hydroxyl sites on the particle surface that interact with latex molecules, forming a more compact network structure. Therefore, the bonding performance and water resistance of the adhesive were enhanced. In addition, rheology results showed that the adhesive behaves as a pseudoplastic fluid. Small-angle X-ray scattering and energy dispersive spectroscopy confirmed the good compatibility and dispersion of nano-TiO2 in the adhesive films. Diffusing wave spectroscopy and scanning electron microscopy showed that smaller TiO2 particles were more favorable for the formation of smoother and denser films. These results are of great significance for improving the structure and properties of starch-based wood adhesives and preparing high-performance environmentally friendly biobased adhesives.
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Adesivos , Amido , Amido/química , Adesivos/química , Madeira/química , Tamanho da PartículaRESUMO
Over the past few decades of rapid development, China has always attached great importance to the redevelopment of rural areas. Since the 19th National Congress of the Communist Party of China, the rural revitalization strategy proposed at the meeting has always received extensive attention. In 2019, the Chinese central government released a document on its rural revitalization strategy. In the document, Guizhou Province was listed as a key area to receive focus on pursuing rural revitalization. Meanwhile, the Guizhou government also formulated The Implementation Opinions on the People's Government of Guizhou Province's Rural Revitalization Strategy. The aim of this paper is to try to establish a model according to the rural revitalization strategy proposed by the Guizhou government and extracts the main influencing factors from its analysis. Through the analysis of the data collected during the process of the rural revitalization, the paper undertakes a deep analysis of the evaluation and studies an optimized approach to the revitalization to provide a referenced review for other villages.
Assuntos
População Rural , China , HumanosRESUMO
A rapid, simple, highly efficiency analytical method for detecting kitasamycin A1, A4, A5, and A13 in different feedstuffs was successfully developed by combining enhanced matrix removal (EMR) lipid cartridge and ultra-high performance liquid chromatography tandem mass spectrometry (UHPLC-MS/MS). After extraction with acetonitrile, the sample supernatants were directly passed through the EMR lipid cartridge. Then, the cartridge was rinsed and eluted with acetonitrile and methanol, respectively, followed by UHPLC-MS/MS analysis with positive mode using multiple reaction monitoring. Optimized pretreatment procedure without solvent conversion, multiple nitrogen drying steps and activated cartridge before loading, and no significant interference were found during the analysis of different types of animal feedstuffs. Excellent sensitivity (Limit of quantification, LOQ) of kitasamycin A1, A4, A5, and A13 was 1.1-2.0 µg/kg. Satisfactory recoveries of kitasamycin A1, A4, A5, and A13 in different feedstuffs were from 74.0% to 98.8%, with the relative standard deviations (RSDs) below 10.4%, and good linear correlation coefficient (r)>0.9990 in the matrix matched standard curve range of 0.02-50.0 µg/L. Results demonstrated that the developed method exhibited excellent linearity, accuracy, precision, sensitivity, and the feasibility of using this method in kitasamycin determination of animal feedstuffs. The method was evaluated using the greenness analysis method through Eco-Scale assessment tool.
Assuntos
Kitasamicina , Espectrometria de Massas em Tandem , Acetonitrilas , Animais , Cromatografia Líquida de Alta Pressão/métodos , Lipídeos , Extração em Fase Sólida , Espectrometria de Massas em Tandem/métodosRESUMO
The initiation and development of storage roots (SRs) are intricately regulated by a transcriptional regulatory network. One key challenge is to accurately pinpoint the tipping point during the transition from pre-swelling to SRs and to identify the core regulators governing such a critical transition. To solve this problem, we performed a dynamic network biomarker (DNB) analysis of transcriptomic dynamics during root development in Ipomoea batatas (sweet potato). First, our analysis identified stage-specific expression patterns for a significant proportion (>9%) of the sweet potato genes and unraveled the chronology of events that happen at the early and later stages of root development. Then, the results showed that different root developmental stages can be depicted by co-expressed modules of sweet potato genes. Moreover, we identified the key components and transcriptional regulatory network that determine root development. Furthermore, through DNB analysis an early stage, with a root diameter of 3.5 mm, was identified as the critical period of SR swelling initiation, which is consistent with morphological and metabolic changes. In particular, we identified a NAM/ATAF/CUC (NAC) domain transcription factor, IbNAC083, as a core regulator of this initiation in the DNB-associated network. Further analyses and experiments showed that IbNAC083, along with its associated differentially expressed genes, induced dysfunction of metabolism processes, including the biosynthesis of lignin, flavonol and starch, thus leading to the transition to swelling roots.
Assuntos
Ipomoea batatas/genética , Proteínas de Plantas/genética , Tubérculos/crescimento & desenvolvimento , Tubérculos/genética , Regulação da Expressão Gênica de Plantas , Redes Reguladoras de Genes , Marcadores Genéticos , Ipomoea batatas/crescimento & desenvolvimento , Lignina/metabolismo , Fenótipo , Raízes de Plantas/genética , Raízes de Plantas/crescimento & desenvolvimento , Plantas Geneticamente Modificadas , Regiões Promotoras Genéticas , Amido/metabolismo , Açúcares/metabolismoRESUMO
The residual behaviors and dietary risk probability of 12 pesticides in Dendrobium officinale Kimura et Migo cultivated at two representative locations under green house conditions were investigated using liquid chromatography-tandem mass spectrometry. Field trials showed that the half-lives of 12 pesticides ranged from 0.9 to 14.4 days in fresh D. officinale stems. Based on maximum residue levels (MRLs), the ultimate residues of imidacloprid, dimethomorph, metalaxyl, tebuconazole, and cyazofamid at a pre-harvest interval (PHI) of 28 days were within acceptable limits. For abamectin, indoxacarb, and difenoconazole, 35-day PHIs were needed. The PHIs of trifloxystrobin and fluopyram were 42 days, the time required for their residues to be reduced to an MRL of 4 mg/kg. The chronic and acute risk quotients of target pesticides at PHIs of 28-42 days were below 5.929% and 0.532%, respectively, showing that the evaluated D. officinale exhibited an acceptably low dietary risk to the general population.
Assuntos
Dendrobium , Resíduos de Praguicidas , Praguicidas , Cromatografia Líquida , Humanos , Resíduos de Praguicidas/análise , Medição de RiscoRESUMO
Storage roots of sweet potato are important sink organs for photoassimilates and energy, and carbohydrate metabolism in storage roots affects yield and starch production. Our previous study showed that sweet potato H+-pyrophosphatase (IbVP1) plays a vital role in mitigating iron deficiency and positively controls fibrous root growth. However, its roles in regulating starch production in storage roots have not been investigated. In this study, we found that IbVP1 overexpression in sweet potato improved the photosynthesis ability of and sucrose content in source leaves and increased both the starch content in and total yield of sink tissues. Using 13C-labeled sucrose feeding, we determined that IbVP1 overexpression promotes phloem loading and sucrose long-distance transport and enhances Pi-use efficiency. In sweet potato plants overexpressing IbVP1, the expression levels of starch biosynthesis pathway genes, especially AGPase and GBSSI, were upregulated, leading to changes in the structure, composition, and physicochemical properties of stored starch. Our study shows that the IbVP1 gene plays an important role in regulating starch metabolism in sweet potato. Application of the VP1 gene in genetic engineering of sweet potato cultivars may allow the improvement of starch production and yield under stress or nutrient-limited conditions.
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CRISPR/Cas9-mediated genome editing is a powerful technology that has been used for the genetic modification of a number of crop species. In order to evaluate the efficacy of CRISPR/Cas9 technology in the root crop, sweet potato (Ipomoea batatas), two starch biosynthetic pathway genes, IbGBSSI (encoding granule-bound starch synthase I), and IbSBEII (encoding starch branching enzyme II), were targeted in the starch-type cultivar Xushu22 and carotenoid-rich cultivar Taizhong6. I. batatas was transformed using a binary vector, in which the Cas9 gene is driven by the Arabidopsis AtUBQ promoter and the guide RNA is controlled by the Arabidopsis AtU6 promoter. A total of 72 Xushu22 and 35 Taizhong6 transgenic lines were generated and analyzed for mutations. The mutation efficiency was 62-92% with multi-allelic mutations in both cultivars. Most of the mutations were nucleotide substitutions that lead to amino acid changes and, less frequently, stop codons. In addition, short nucleotide insertions or deletions were also found in both IbGBSSI and IbSBEII. Furthermore, a 2658 bp deletion was found in one IbSBEII transgenic line. The total starch contents were not significantly changed in IbGBSSI- and IbSBEII-knockout transgenic lines compared to the wild-type control. However, in the allopolyploid sweet potato, the IbGBSSI-knockout reduced, while the IbSBEII-knockout increased, the amylose percentage. Our results demonstrate that CRISPR/Cas9 technology is an effective tool for the improvement of starch qualities in sweet potato and breeding of polyploid root crops.
Assuntos
Sistemas CRISPR-Cas , Genes de Plantas , Ipomoea batatas , Mutagênese , Plantas Geneticamente Modificadas , Amido , Arabidopsis/genética , Ipomoea batatas/genética , Ipomoea batatas/metabolismo , Plantas Geneticamente Modificadas/genética , Plantas Geneticamente Modificadas/metabolismo , Regiões Promotoras Genéticas , Amido/biossíntese , Amido/genéticaRESUMO
An improved quick, easy, cheap, effective, rugged, and safe (QuEChERS) method combined with ultrapressure liquid chromatography tandem mass spectrometric method (UPLC-MS/MS) was developed to simultaneously determine 25 pesticides in Zizania latifolia. The samples were extracted with methanol(MeOH) and 0.1% formic acid (80:20, v/v) and cleaned with C18 absorbent and primary-secondary amine (PSA). LC separation was performed on a BEH C18 UPLC column under the condition of gradient elution with the mobile phase consisted of 0.5% formic acid (10 mM ammonium acetate)/MeOH. External standard calibration method with matrix-matched was used for quantification, and good linearity was obtained over a concentration range of 0.5-100 µg/l, with correlation coefficients greater than 0.9901. The limit of detection (LOD) and the limit of quantitation (LOQ) of the 25 pesticides were in the range of 0.2-1.0 µg/kg and 0.5-3.3 µg/kg, respectively. The recoveries ranged from 72% to 118%, and the relative standard deviations (RSDs) were less than 20%. Thus, the proposed method is suitable for the simultaneous determination of 25 pesticides in Z. latifolia.
Assuntos
Cromatografia Líquida/métodos , Oryza/química , Praguicidas/análise , Extração em Fase Sólida/métodos , Espectrometria de Massas em Tandem/métodos , Limite de DetecçãoRESUMO
An ultra-performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS) method for the simultaneous quantitative determination of ten cephalosporins in bee products, including honey, royal jelly, and lyophilized royal jelly powder, has been established. The samples were extracted with an acetonitrile-water (80:20, v/v) solution. After purification by solid phase extraction using an Oasis PRIME HLB cartridge, the extract was blown to dryness under a stream of nitrogen gas and then re-dissolved in 1 mL 0.1% (v/v) formic acid solution and methanol (95:5, v/v). The samples were separated on an Acquity UPLC BEH C18 column, using a mixture of 0.1% (v/v) formic acid solution and methanol as the mobile phase under gradient elution. The analysis was carried out using a positive electrospray ion source in the multiple reaction monitoring mode. The matrix-matched external standard method was applied to quantitative analysis. Good linear relationships were obtained for the ten cephalosporins in certain concentration ranges, and the correlation coefficients were more than 0.999. The limits of detection and limits of quantification for the ten cephalosporins were in the ranges 0.15-1.5 µg/kg and 0.5-5 µg/kg, respectively. The recoveries for the analytes in the bee products were in the range of 75.0%to 89.8%, with relative standard deviations of 1.4% to 4.6%. This method is characterized by a short analysis time and is suitable for the determination of cephalosporins in different bee products by virtue of its simplicity and reliability.
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Glycosylation contributes to the diversity and stability of anthocyanins in plants. The process is catalysed by various glucosyltransferases using different anthocyanidin aglycones and glycosyl donors. In this study, we found that an anthocyanidin 3-O-glucoside-2â³-O-glucosyltransferase (3GGT) from purple sweet potato (Ipomoea batatas) catalyses the conversion of anthocyanidin 3-O-glucoside into anthocyanidin 3-O-sophoroside, which is functionally different from the 3GGT ortholog of Arabidopsis. Phylogenetic analysis indicated regioselectivity of 3GGT using uridine-5'-diphosphate (UDP)-xylose or UDP-glucose as the glycosyl is divergent between Convolvulaceae and Arabidopsis. Homology-based protein modeling and site-directed mutagenesis of Ib3GGT and At3GGT suggested that the Thr-138 of Ib3GGT is a key amino acid residue for UDP-glucose recognition and that it plays a major role in sugar-donor selectivity. Wild-type and ugt79b1 mutants (defective in UDP carbohydrate-dependent glycosyltransferases, UGTs) of Arabidopsis plants overexpressing Ib3GGT produced the new component cyanidin 3-O-sophoroside. Moreover, Ib3GGT expression was associated with anthocyanin accumulation in different tissues during I. batatas plant development and was regulated by the transcription factor IbMYB1. Localization assays for Ib3GGT showed that glycosyl extension occurs in the cytosol and not in the endoplasmic reticulum. This study therefore reveals the function of Ib3GGT in glycosyl extension of anthocyanins and demonstrates that Thr-138 is the key amino acid residue for UDP-glucose recognition.
Assuntos
Antocianinas/metabolismo , Glucose/metabolismo , Glicosiltransferases/genética , Ipomoea batatas/genética , Proteínas de Plantas/genética , Sequência de Aminoácidos , Arabidopsis/genética , Arabidopsis/metabolismo , Catálise , Glicosiltransferases/química , Glicosiltransferases/metabolismo , Ipomoea batatas/metabolismo , Filogenia , Proteínas de Plantas/química , Proteínas de Plantas/metabolismo , Plantas Geneticamente Modificadas/genética , Plantas Geneticamente Modificadas/metabolismo , Alinhamento de SequênciaRESUMO
AIM: Immune-related lncRNA may influence osteoarthritis (OA) susceptibility. We conducted this study to assess whether the genetic variants in several immune-related lncRNA influence OA susceptibility. METHODS: The current research genotyped four SNPs in 306 OA patients and 316 healthy controls, including PRNCR1 rs7463708, PRNCR1 rs1456315, PRNCR1 rs16901946 and KIF13B1 rs643472, to investigate their associations with OA susceptibility. RESULTS: We identified that PRNCR1 rs1456315 was associated with OA susceptibility in Chinese Han population (recessive model: odds ratio = 2.24; 95% CI: 1.05-4.81; additive model: odds ratio = 1.36; 95% CI: 1.03-1.80). CONCLUSION: Individuals with PRNCR1 rs1456315 mutant G allele were more likely to suffer from OA in Chinese Han population.
Assuntos
Cinesinas/genética , Osteoartrite/genética , RNA Longo não Codificante/genética , Alelos , Povo Asiático/genética , Estudos de Casos e Controles , China , Etnicidade/genética , Frequência do Gene/genética , Estudos de Associação Genética/métodos , Predisposição Genética para Doença/genética , Variação Genética , Genótipo , Humanos , Cinesinas/fisiologia , Osteoartrite do Joelho/genética , Polimorfismo de Nucleotídeo Único/genética , RNA Longo não Codificante/fisiologia , Fatores de RiscoRESUMO
Iron (Fe) deficiency is one of the most common micronutrient deficiencies limiting crop production globally, especially in arid regions because of decreased availability of iron in alkaline soils. Sweet potato [Ipomoea batatas (L.) Lam.] grows well in arid regions and is tolerant to Fe deficiency. Here, we report that the transcription of type I H+ -pyrophosphatase (H+ -PPase) gene IbVP1 in sweet potato plants was strongly induced by Fe deficiency and auxin in hydroponics, improving Fe acquisition via increased rhizosphere acidification and auxin regulation. When overexpressed, transgenic plants show higher pyrophosphate hydrolysis and plasma membrane H+ -ATPase activity compared with the wild type, leading to increased rhizosphere acidification. The IbVP1-overexpressing plants showed better growth, including enlarged root systems, under Fe-sufficient or Fe-deficient conditions. Increased ferric precipitation and ferric chelate reductase activity in the roots of transgenic lines indicate improved iron uptake, which is also confirmed by increased Fe content and up-regulation of Fe uptake genes, e.g. FRO2, IRT1 and FIT. Carbohydrate metabolism is significantly affected in the transgenic lines, showing increased sugar and starch content associated with the increased expression of AGPase and SUT1 genes and the decrease in ß-amylase gene expression. Improved antioxidant capacities were also detected in the transgenic plants, which showed reduced H2 O2 accumulation associated with up-regulated ROS-scavenging activity. Therefore, H+ -PPase plays a key role in the response to Fe deficiency by sweet potato and effectively improves the Fe acquisition by overexpressing IbVP1 in crops cultivated in micronutrient-deficient soils.
Assuntos
Pirofosfatase Inorgânica/metabolismo , Ipomoea batatas/enzimologia , Ipomoea batatas/metabolismo , Ferro/metabolismo , Proteínas de Plantas/metabolismo , Regulação da Expressão Gênica de Plantas/genética , Regulação da Expressão Gênica de Plantas/fisiologia , Ácidos Indolacéticos/metabolismo , Pirofosfatase Inorgânica/genética , Ipomoea batatas/genética , Proteínas de Plantas/genética , Raízes de Plantas/enzimologia , Raízes de Plantas/genética , Raízes de Plantas/metabolismo , Plantas Geneticamente Modificadas/enzimologia , Plantas Geneticamente Modificadas/genética , Plantas Geneticamente Modificadas/metabolismoRESUMO
A LC-MS/MS method for determination of eight pesticides (triadimefon, sulfoxaflor, flusilazole, tebuconazole, difenoconazole, amitraz, azoxystrobin, and thiophanate-methyl) in Lycium barbarum was established. The samples were extracted with acetonitrile, and then cleaned up by primary secondary amine. The extracts were diluted with 0.1% formic acid in water. The results showed that at the fortified levels of 0.01-10mg/kg, the average recoveries of these pesticides ranged from 82.1% to 96.2% with the relative standard deviations lower than 7%. The half-lives of eight pesticides were 1.3-5.0days in Lycium barbarum fruits. The pre-harvest interval of all pesticides mentioned above were investigated. Tebuconazole (14days), sulfoxaflor (14days) and flusilazole (28days) have longer pre-harvest interval than the others which have 7days. The dietary risks, assessed as hazard quotients, were far below 100%. The results showed that the eight pesticides applied to Lycium barbarum were comparably safe for the consumer.
Assuntos
Cromatografia Líquida/métodos , Lycium/química , Praguicidas/análise , Espectrometria de Massas em Tandem/métodos , Acetonitrilas/química , Medição de RiscoRESUMO
A new analytical method for the determination of ribavirin in chicken muscle using a QuEChERS (Quick, Easy, Cheap, Effective, Rugged and Safe) method and liquid chromatography-tandem mass spectrometry (LC-MS-MS) was developed and validated. Samples were extracted with acidified methanol (methanol:acetic acid, 99:1, v/v). The extract was further purified by QuEChERS method using primary-secondary amine (PSA) and C18. Finally, the extract was dried by nitrogen under 45°C and reconstituted in water. The separation was performed on a Hypercarb analytical column under a gradient elution. The mobile phase was composed of water buffered with ammonium acetate (2.0mM) and acetonitrile. The proposed method was validated according to the European Commission Decision 2002/657/EC. The values of the decision limit (CCα) and the detection capability (CCß) were 1.1 and 1.5µg/kg, respectively. The mean recoveries of ribavirin ranged from 94.2% to 99.2%. The repeatability (expressed as coefficient of variation, CVr) of the method ranged from 4.5% to 4.9% and the reproducibility (CVR) of the method ranged from 4.8% to 5.4%. The method is demonstrated to be suitable for the determination of ribavirin in chicken muscle in conformity with the current EU performance requirements through validation. The total time required for the analysis of one sample, including sample preparation, was about 45min.
Assuntos
Cromatografia Líquida/métodos , Resíduos de Drogas/análise , Carne/análise , Músculo Esquelético/química , Ribavirina/análise , Espectrometria de Massas em Tandem/métodos , Animais , Galinhas , Cromatografia Líquida/economia , Limite de Detecção , Modelos Lineares , Reprodutibilidade dos Testes , Espectrometria de Massas em Tandem/economiaRESUMO
A modified quick, easy, cheap, effective, rugged, and safe (QuEChERS) method using multi-walled carbon nanotubes (MWCNTs) as a reversed-dispersive solid phase extraction (r-dSPE) material combined with ultra-high liquid chromatography tandem mass spectrometry (UHPLC-MS/MS) was developed for the simultaneous determination of 16 novel amide fungicides in vegetables and fruits. After extraction with acetonitrile, a dSPE cleanup procedure, which was developed after the optimization of the type and amount of MWCNTs, the pH value of the extract, the extraction time for MWCNTs, and the type of eluent with MWCNTs material, was conducted. The determination of the target compounds was conducted in less than 7.0 min while the specificity is ensured through the MRM acquisition mode. The linearity of the analytical response across the studied range of concentrations (0.25-500 µg/L) was excellent, obtaining correlation coefficients higher than 0.997. The samples were quantified with the matrix matched standard solutions. The average recoveries in cabbage, celery, strawberry, and grape at three spiked levels (0.01, 0.5, and 5.0mg/kg) were ranged from 72.4 to 98.5% with all RSDs lower than 10%. The limits of detection were below 0.003 mg/kg and the limits of quantification did not exceed 0.01 mg/kg in all matrices. The method demonstrated to be suitable for the simultaneous determination of 16 novel amide fungicides in vegetables and fruits.