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LC/ MS-MS analysis of tea

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https://www.readbyqxmd.com/read/27725073/high-throughput-analytical-techniques-for-the-determination-of-the-residues-of-653-multiclass-pesticides-and-chemical-pollutants-in-tea-part-vii-a-gc-ms-gc-ms-ms-and-lc-ms-ms-study-of-the-degradation-profiles-of-pesticide-residues-in-green-tea
#1
Jie Li, Fang Yang, Qiao-Ying Chang, Guo-Fang Pang, Hui Chen, Chun-Lin Fan
GC-MS, GC-tandem MS (MS/MS), and LC-MS/MS were used to mathematically define the degradation profiles of pesticide residues in two field trials. Nineteen pesticides were studied in the first field trial and 11 in the second. The results of the field trials demonstrated that the degradation profiles of pesticide residues in green tea can be described with power functions to successfully estimate the amount of time, following pesticide application, pesticide residues appearing in tea in concentrations at and/or above the maximum residue limit (MRL) decrease to concentrations below the MRL...
October 8, 2016: Journal of AOAC International
https://www.readbyqxmd.com/read/27619091/golf-ball-assisted-electrospray-ionization-of-mass-spectrometry-for%C3%A2-the%C3%A2-determination-of-trace-amino-acids-in-complex-samples
#2
Yen-Hsien Li, Chung-Yu Chen, Cheng-Hsiung Kuo, Maw-Rong Lee
During the electrospray ionization (ESI) process, ions move through a heated capillary aperture to be detected on arrival at a mass analyzer. However, the ESI process creates an ion plume, which expands into an ion cloud with an area larger than that of the heated capillary aperture, significantly contributing to an ion loss of 50% due to coulombic repulsion. The use of DC and RF fields to focus ions from the ion source into the vacuum chamber has been proposed in the literature, but the improvement of ion transmission efficiency is limited...
September 28, 2016: Analytica Chimica Acta
https://www.readbyqxmd.com/read/27507726/automated-multi-plug-filtration-cleanup-for-liquid-chromatographic-tandem-mass-spectrometric-pesticide-multi-residue-analysis-in-representative-crop-commodities
#3
Yuhong Qin, Jingru Zhang, Yuan Zhang, Fangbing Li, Yongtao Han, Nan Zou, Haowei Xu, Meiyuan Qian, Canping Pan
An automated multi-plug filtration cleanup (m-PFC) method on modified QuEChERS (quick, easy, cheap, effective, rugged, and safe) extracts was developed. The automatic device was aimed to reduce labor-consuming manual operation workload in the cleanup steps. It could control the volume and the speed of pulling and pushing cycles accurately. In this work, m-PFC was based on multi-walled carbon nanotubes (MWCNTs) mixed with other sorbents and anhydrous magnesium sulfate (MgSO4) in a packed tip for analysis of pesticide multi-residues in crop commodities followed by liquid chromatography with tandem mass spectrometric (LC-MS/MS) detection...
September 2, 2016: Journal of Chromatography. A
https://www.readbyqxmd.com/read/27211616/optimized-combination-of-dilution-and-refined-quechers-to-overcome-matrix-effects-of-six-types-of-tea-for-determination-eight-neonicotinoid-insecticides-by-ultra-performance-liquid-chromatography-electrospray-tandem-mass-spectrometry
#4
Weiting Jiao, Yu Xiao, Xiaosan Qian, Mengmeng Tong, Yizheng Hu, Ruyan Hou, Rimao Hua
Liquid chromatography-electrospray ionization tandem mass spectrometry (LC-ESI-MS/MS) is a primary tool for analysis of low volatility compounds in complex matrices. However, complex matrices, such as different types of tea, complicate analysis through ionization suppression or enhancement. In this study, sample preparation by a refined QuEChERS method combined with a dilution strategy removed almost all matrix effects caused by six types of tea. Tea samples were soaked with water and extracted with acetonitrile, cleaned up with a combination of PVPP (160mg) and GCB (20mg), and dried...
November 1, 2016: Food Chemistry
https://www.readbyqxmd.com/read/27137993/swapdt-a-method-for-short-time-withering-assessment-of-probability-for-drought-tolerance-in-camellia-sinensis-validated-by-targeted-metabolomics
#5
Christopher Nyarukowa, Robert Koech, Theodor Loots, Zeno Apostolides
Climate change is causing droughts affecting crop production on a global scale. Classical breeding and selection strategies for drought-tolerant cultivars will help prevent crop losses. Plant breeders, for all crops, need a simple and reliable method to identify drought-tolerant cultivars, but such a method is missing. Plant metabolism is often disrupted by abiotic stress conditions. To survive drought, plants reconfigure their metabolic pathways. Studies have documented the importance of metabolic regulation, i...
July 1, 2016: Journal of Plant Physiology
https://www.readbyqxmd.com/read/26782294/bioanalytical-lc-ms-study-of-potential-bacterial-transglycosylation-inhibitors
#6
Bart Blanchaert, Ismail Murat Palabiyik, Alper Gökbulut, Ming-Juan Wang, Zhong Dai, Feng Wei, Shuang-Cheng Ma, Erwin Adams, Ann Van Schepdael
Bacterial transglycosylation is an interesting target in antibiotic drug development. An in vitro transglycosylation assay was developed and used to search for possible inhibitors of Staphylococcus aureus Penicillin Binding Protein 2-mediated transglycosylation. Since the substrate, Lipid II, has no UV-chromophore, the assay relies on LC coupled to MS for analysis of the incubation mixtures. Extracts from Thymus sipyleus, Salvia verticillata, Salvia virgata and Oolong tea were tested, as well as epigallocatechin gallate and ursolic acid, which are chemical compounds derived from plants...
August 5, 2016: Journal of Pharmaceutical and Biomedical Analysis
https://www.readbyqxmd.com/read/26608291/lc-ms-based-metabolomic-investigation-of-chemopreventive-phytochemical-elicited-metabolic-events
#7
Lei Wang, Dan Yao, Chi Chen
Phytochemicals are under intensive investigation for their potential use as chemopreventive agents in blocking or suppressing carcinogenesis. Metabolic interactions between phytochemical and biological system play an important role in determining the efficacy and toxicity of chemopreventive phytochemicals. However, complexities of phytochemical biotransformation and intermediary metabolism pose challenges for studying phytochemical-elicited metabolic events. Metabolomics has become a highly effective technical platform to detect subtle changes in a complex metabolic system...
2016: Methods in Molecular Biology
https://www.readbyqxmd.com/read/26607316/online-screening-of-nitric-oxide-scavengers-in-natural-products-using-high-performance-liquid-chromatography-coupled-with-tandem-diode-array-and-fluorescence-detection
#8
Dapeng Li, Ting Wang, Yujie Guo, Yuanjia Hu, Boyang Yu, Jin Qi
Nitric oxide (NO) is an important cellular signaling molecule with extensive physiological and pathophysiological effects. NO scavengers have the potential to treat inflammation, septic shock and other related diseases, and numerous examples have been chemically synthesized or isolated from natural products. The chemical diversity of natural products, however, means that a huge effort is necessary to efficiently screen and identify bioactive compounds, especially NO scavengers. In this article, we propose an effective analytical method to screen for NO scavengers in three natural products using an online system that couples high performance liquid chromatography with tandem diode array and fluorescence detection (HPLC-DAD-FLD)...
December 18, 2015: Journal of Chromatography. A
https://www.readbyqxmd.com/read/26578210/simultaneous-analysis-of-mono-di-and-tri-ethanolamine-in-cosmetic-products-using-liquid-chromatography-coupled-tandem-mass-spectrometry
#9
Kyong-Oh Shin, Yong-Moon Lee
Alkanolamines such as monoethanolamine (MEA), diethanolamine (DEA), and triethanolamine (TEA) are used as wetting agents in shampoos, lotions, creams, and other cosmetics. DEA is widely used to provide lather in shampoos and maintain a favorable consistency in lotions and creams. Although DEA is not harmful, it may react with other ingredients in the cosmetic formula after extended storage periods to form an extremely potent carcinogen called nitrosodiethanolamine (NDEA), which is readily absorbed through the skin and has been linked to the development of stomach, esophagus, liver, and bladder cancers...
January 2016: Archives of Pharmacal Research
https://www.readbyqxmd.com/read/26551209/quantitative-analysis-of-intracellular-nucleoside-triphosphates-and-other-polar-metabolites-using-ion-pair-reversed-phase-liquid-chromatography-coupled-with-tandem-mass-spectrometry
#10
Jianmei Wu, Yingtao Zhang, Richard Wiegand, Jian Wang, Gerold Bepler, Jing Li
Simultaneous, quantitative determination of intracellular nucleoside triphosphates and other polar metabolites using liquid chromatography with electrospray ionization tandem mass spectrometry (LC-MS/MS) represents a bioanalytic challenge because of charged, highly hydrophilic analytes presented at a large concentration range in a complex matrix. In this study, an ion pair LC-MS/MS method using triethylamine (TEA)-hexafluoroisopropanol (HFIP) ion-pair mobile phase was optimized and validated for simultaneous and unambiguous determination of 8 nucleoside triphosphates (including ATP, CTP, GTP, UTP, dATP, dCTP, dGTP, and dTTP) in cellular samples...
December 1, 2015: Journal of Chromatography. B, Analytical Technologies in the Biomedical and Life Sciences
https://www.readbyqxmd.com/read/26525263/high-throughput-analytical-techniques-for-the-determination-and-confirmation-of-residues-of-653-multiclass-pesticides-and-chemical-pollutants-in-tea-by-gc-ms-gc-ms-ms-and-lc-ms-ms-collaborative-study-first-action-2014-09
#11
Guo-Fang Pang, Chun-Lin Fan, Yan-Zhong Cao, Fang Yan, Yan Li, Jian Kang, Hui Chen, Qiao-Ying Chang
Thirty laboratories from fom North and South America, Europe, and Asia participated in this AOAC collaborative study (15 from China; five from Germany; two each from Italy and the United States; and one each from the Republic of Korea, Canada, Spain, Japan, Belgium, and India). Participants represented government regulatory, commercial testing, university, research institute, and private laboratories. The single-laboratory validated (SLV) tea method was evaluated in the collaborative study to determine the recovery and reproducibility of the method under multilaboratory conditions...
September 2015: Journal of AOAC International
https://www.readbyqxmd.com/read/26404216/enhanced-bioaccessibility-of-crocetin-sugar-esters-from-saffron-in-infusions-rich-in-natural-phenolic-antioxidants
#12
Stella A Ordoudi, Anastasia Kyriakoudi, Maria Z Tsimidou
The present study aims to examine whether and to what extent the bioaccessibility of the major saffron apocarotenoids, namely crocetin sugar esters (CRTSEs), is affected by the presence of strong water-soluble antioxidants, ingredients of the herbs found in commercial tea blends with saffron. An in vitro digestion model was applied to infusions from these products to investigate the possible changes. All of the studied infusions were rich in total phenols (9.9-22.5 mg caffeic acid equivalents/100 mg dry infusion) and presented strong DPPH radical scavenging activity regardless of the composition of the corresponding herbal blends...
2015: Molecules: a Journal of Synthetic Chemistry and Natural Product Chemistry
https://www.readbyqxmd.com/read/26349944/determination-of-the-oxidative-stress-biomarker-urinary-8-hydroxy-2-deoxyguanosine-by-automated-on-line-in-tube-solid-phase-microextraction-coupled-with-liquid-chromatography-tandem-mass-spectrometry
#13
Hiroyuki Kataoka, Keisuke Mizuno, Eri Oda, Akihiro Saito
A simple and sensitive method for the determination of 8-hydroxy-2'-deoxyguanosine (8-OHdG), a marker of oxidative DNA damage in human urine, was developed using automated on-line in-tube solid-phase microextraction (SPME) coupled with stable isotope-dilution liquid chromatography-tandem mass spectrometry (LC-MS/MS). Creatinine was also analyzed simultaneously to normalize urine volume by the in-tube SPME LC-MS/MS method, and 8-OHdG and creatinine were separated within 3 min using a Zorbax Eclipse XDB-C8 column...
April 15, 2016: Journal of Chromatography. B, Analytical Technologies in the Biomedical and Life Sciences
https://www.readbyqxmd.com/read/26299992/development-of-lc-ms-ms-analysis-of-cyclic-dipeptides-and-its-application-to-tea-extract
#14
Kenji Yamamoto, Miki Hayashi, Yuka Murakami, Yoko Araki, Yuuki Otsuka, Takehiro Kashiwagi, Tomoko Shimamura, Hiroyuki Ukeda
2,5-Diketopiperazines (DKPs), also called cyclic dipeptides, have been known to occur in various foods. Recently, DKPs have attracted attentions as bioactive components. There were some reports on analytical methods for DKPs, but the number of analyzed DKPs was only a part of all DKPs and the quantitative performance was not studied in detail. In this study, we selected 31 kinds of DKPs and developed a quantitative and simultaneous analytical method using LC-MS/MS. This method was applied to DKPs determination in Pu-erh tea, post-fermentation tea, and 18 kinds of DKPs were determined at concentration of 0...
2015: Bioscience, Biotechnology, and Biochemistry
https://www.readbyqxmd.com/read/26183930/a-novel-method-based-on-mspd-for-simultaneous-determination-of-16-pesticide-residues-in-tea-by-lc-ms-ms
#15
Yalin Cao, Hua Tang, Dazhou Chen, Lei Li
A novel method based on matrix solid phase dispersion (MSPD) coupled with liquid chromatography-tandem mass spectrometry was established for the determination and the quantification of 16 pesticides (5 carbamates, 4 organophosphorus, and 7 pyrethroids) in various tea. Matrix dispersive sorbent and further cleanup sorbent were applied to improve the efficiency of extraction and purification. PVPP, PSA and GCB were introduced as further cleanup sorbents packed at the bottom of the MSPD to remove co-eluting matrix components...
August 15, 2015: Journal of Chromatography. B, Analytical Technologies in the Biomedical and Life Sciences
https://www.readbyqxmd.com/read/26065738/aldehyde-formation-in-frozen-mackerel-scomber-scombrus-in-the-presence-and-absence-of-instant-green-tea
#16
Rabia Alghazeer, Suhur Saeed, Nazlin K Howell
The effect of frozen storage on lipid peroxidation in Atlantic mackerel (Scomber scombrus) stored for up to 26 weeks at -10 or -80°C (control), with and without green tea antioxidants, was investigated. Hydroperoxides (PV) and aldehydes (TBARS) were measured by HPLC and LC-MS and hexanal by GC. There was an increase in peroxide value which was associated with an increase in aldehydes, followed by hexanal increase with storage time and at a higher temperature of -10°C compared with samples stored at -80°C...
June 1, 2008: Food Chemistry
https://www.readbyqxmd.com/read/26059158/quantitative-analysis-of-acrylamide-in-tea-by-liquid-chromatography-coupled-with-electrospray-ionization-tandem-mass-spectrometry
#17
Jie Liu, Ganghua Zhao, Yuan Yuan, Fang Chen, Xiaosong Hu
An effective sample preparation procedure was optimized and a liquid chromatography-tandem mass spectrometry (LC-MS/MS) was developed for the quantitative analysis of acrylamide in tea. [(13)C3]-acrylamide was used as internal standard. Acrylamide was extracted at 25°C for 20min by 10ml water followed by 10ml acetonitrile, and then 4g of magnesium sulfate and 0.5g of sodium chloride were added to the above mixture under stirring thoroughly. In order to increase the response of acrylamide, 9ml acetonitrile layer was taken and concentrated to 0...
May 15, 2008: Food Chemistry
https://www.readbyqxmd.com/read/26036873/comparative-proteomic-analysis-using-2de-lc-ms-ms-reveals-the-mechanism-of-fuzhuan-brick-tea-extract-against-hepatic-fat-accumulation-in-rats-with-nonalcoholic-fatty-liver-disease
#18
COMPARATIVE STUDY
Zhonghua Liu, Yong Lin, Sheng Zhang, Die Wang, Qionglin Liang, Guoan Luo
Fuzhuan brick tea has received increasing attention in recent years owing to its benefits for nonalcoholic fatty liver disease (NAFLD) and associated metabolic syndrome. For exploring the ameliorative mechanism, the liver proteomes from three groups of rats fed either a normal control diet (NCD), a high fat diet (HFD), or a HFD supplemented with high-dose Fuzhuan brick tea extract (FTE) (HFD + HFTE) were comprehensively compared by quantitative proteomics using 2DE-LC-MS/MS. This is the first study of the effects of tea aqueous extract on the liver proteome of rats suffering from metabolic syndrome...
September 2015: Electrophoresis
https://www.readbyqxmd.com/read/25997469/metabolomics-and-proteomics-and-what-to-do-with-all-these-omes-insights-from-nutrigenomic-investigations-in-new-zealand
#19
REVIEW
Matthew Barnett, Wayne Young, Janine Cooney, Nicole Roy
BACKGROUND/AIMS: Nutrigenomics New Zealand has invested considerable effort researching the role of nutrient-gene interactions in human inflammatory bowel disease (IBD). This research has utilised a number of 'omics' techniques, including proteomics and metabolomics. METHODS: Mouse models of intestinal inflammation have been used to investigate the mechanisms underlying IBD and to test foods or food components for potential beneficial effects. Proteomics combining two-dimensional gel electrophoresis with liquid chromatography-mass spectrometry (LC-MS) analysis of peptides, and metabolomics using both gas chromatography-MS and LC-MS have been combined with transcriptomics and microbiome analyses to comprehensively assess samples derived from these models...
2014: Journal of Nutrigenetics and Nutrigenomics
https://www.readbyqxmd.com/read/25976808/investigation-on-biochemical-compositional-changes-during-the-microbial-fermentation-process-of-fu-brick-tea-by-lc-ms-based-metabolomics
#20
Jie Xu, Feng-Lin Hu, Wei Wang, Xiao-Chun Wan, Guan-Hu Bao
Fu brick tea (FBT) is a unique post-fermented tea product which is fermented with fungi during the manufacturing process. In this study, we investigated the biochemical compositional changes occurring during the microbial fermentation process (MFP) of FBT based on non-targeted LC-MS, which was a comprehensive and unbiased methodology. Our data analysis took a two-phase approach: (1) comparison of FBT with other tea products using PCA analysis to exhibit the characteristic effect of MFP on the formation of Fu brick tea and (2) comparison of tea samples throughout the MFP of FBT to elucidate the possible key metabolic pathways produced by the fungi...
November 1, 2015: Food Chemistry
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