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Hplc chromatogram of tea

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https://www.readbyqxmd.com/read/27258749/elucidation-of-the-partial-structure-of-polymeric-thearubigins-from-black-tea-by-chemical-degradation
#1
Tetsuo Ozawa, Mari Kataoka, Keiko Morikawa, Osamu Negishi
Butanol-soluble neutral and acidic thearubigins were prepared by a combination of solvent extraction, fractional precipitation, and Toyopearl column chromatography. These pigments showed similar properties to those of Roberts' thearubigins on the paper chromatogram, and a convex broad band with several peaks on reversed-phase HPLC. The thearubigins were methylated, degallated, and chemically degraded with KMnO4 under alkaline conditions. From the degradation products, methyl esters of 4-methoxy benzoic acid, 3,4-dimethoxy benzoic acid, 3,4,5-trimethoxy benzoic acid, 3,4-dimethoxy-1,2-benzenedicarboxylic acid, 3,4-dimethoxy-1,5-benzenedicarboxylic acid, 3,4-dimethoxy-1,6-benzenedicarboxylic acid, 3,4,5-trimethoxy-1,2-benzenedicarboxylie acid, 4,5,6-trimethoxy-1,2,3-benzenetricarboxylic acid, 4,5,4',5'-tetramethoxy-2,2'-diphenic acid, and 3,4,5,3',4',5'-hexamethoxy-2,2'-diphenic acid were detected by using GC-MS and GC-SIM...
January 1996: Bioscience, Biotechnology, and Biochemistry
https://www.readbyqxmd.com/read/25308687/chemical-fingerprint-analysis-for-quality-control-and-identification-of-ziyang-green-tea-by-hplc
#2
Xiaoye He, Jianke Li, Wei Zhao, Run Liu, Lin Zhang, Xianghong Kong
A simple and reliable HPLC fingerprint method was developed and validated for the quality control and identification of Ziyang green tea. Ten batches of Ziyang green tea collected from different plantations in Shaanxi Ziyang of China were used to establish the fingerprint. The feasibility and advantages of the used HPLC fingerprint were verified for its similarity evaluation by systematically comparing chromatograms with professional analytical software recommended by State Food and Drug Administration (SFDA) of China...
March 15, 2015: Food Chemistry
https://www.readbyqxmd.com/read/24308604/a-direct-infusion-and-hplc-esi-orbitrap-ms-approach-for-the-characterization-of-intact-pegylated-proteins
#3
Ines C Forstenlehner, Johann Holzmann, Kai Scheffler, Wolfgang Wieder, Hansjörg Toll, Christian G Huber
The characterization of proteins modified with poly(ethylene glycol) (PEG), such as recombinant human granulocyte-colony stimulating factor (PEGylated rhG-CSF or pegfilgrastim), by electrospray ionization-mass spectrometry (ESI-MS) constitutes a challenge due to the overlapping protein charge state pattern and PEG polydispersity. In order to minimize spectral overlaps, charge reduction by means of the addition of amine was applied. Method development for direct-infusion measurements, carried out on an ESI-time-of-flight (ESI-TOF) instrument, demonstrated the potential of triethylamine (TEA) for shifting the charge state pattern toward lower-charged species and of formic acid (FA) for causing higher charging...
January 7, 2014: Analytical Chemistry
https://www.readbyqxmd.com/read/24176319/geographical-tracing-of-xihu-longjing-tea-using-high-performance-liquid-chromatography
#4
Liyuan Wang, Kang Wei, Hao Cheng, Wei He, Xinghui Li, Wuyun Gong
Xihu Longjing tea (XHLJ) is one of the most famous green tea in China. Due to its high price, some inauthentic XHLJ from other tea producing areas appear on the market and hurt the interests of customers and producers. High-performance liquid chromatography (HPLC) combined with the principal component analysis (PCA) and linear discriminant analysis (LDA) methods were applied to the geographical tracing of XHLJ from two other types of Longjing teas and a non-Longjing flatten-shaped tea (non-LJ). The chromatograms of the tea samples from four different regions were highly similar...
March 1, 2014: Food Chemistry
https://www.readbyqxmd.com/read/22672846/similarity-analyses-of-chromatographic-fingerprints-as-tools-for-identification-and-quality-control-of-green-tea
#5
G Alaerts, J Van Erps, S Pieters, M Dumarey, A M van Nederkassel, M Goodarzi, J Smeyers-Verbeke, Y Vander Heyden
Similarity assessment of complex chromatographic profiles of herbal medicinal products is important as a potential tool for their identification. Mathematical similarity parameters have the advantage to be more reliable than visual similarity evaluations of often subtle differences between the fingerprint profiles. In this paper, different similarity analysis (SA) parameters are applied on green-tea chromatographic fingerprint profiles in order to test their ability to identify (dis)similar tea samples. These parameters are either based on correlation or distance measurements...
December 1, 2012: Journal of Chromatography. B, Analytical Technologies in the Biomedical and Life Sciences
https://www.readbyqxmd.com/read/20219660/composition-standardization-and-chemical-profiling-of-banisteriopsis-caapi-a-plant-for-the-treatment-of-neurodegenerative-disorders-relevant-to-parkinson-s-disease
#6
Yan-Hong Wang, Volodymyr Samoylenko, Babu L Tekwani, Ikhlas A Khan, Loren S Miller, Narayan D Chaurasiya, Md Mostafizur Rahman, Lalit M Tripathi, Shabana I Khan, Vaishali C Joshi, Frank T Wigger, Ilias Muhammad
ETHNOPHARMACOLOGICAL RELEVANCE: Banisteriopsis caapi, a woody vine from the Amazonian basin, is popularly known as an ingredient of a sacred drink ayahuasca, widely used throughout the Amazon as a medicinal tea for healing and spiritual exploration. The usefulness of Banisteriopsis caapi has been established for alleviating symptoms of neurological disorders including Parkinson's disease. AIM OF THE STUDY: Primary objective of this study was to develop the process for preparing standardized extracts of Banisteriopsis caapi to achieve high potency for inhibition of human monoamine oxidases (MAO) and antioxidant properties...
April 21, 2010: Journal of Ethnopharmacology
https://www.readbyqxmd.com/read/19427484/a-chemometric-study-of-chromatograms-of-tea-extracts-by-correlation-optimization-warping-in-conjunction-with-pca-support-vector-machines-and-random-forest-data-modeling
#7
L Zheng, D G Watson, B F Johnston, R L Clark, R Edrada-Ebel, W Elseheri
A reverse phase high performance liquid chromatography (HPLC) separation was established for profiling water soluble compounds in extracts from tea. Whole chromatograms were pre-processed by techniques including baseline correction, binning and normalisation. In addition, peak alignment by correction of retention time shifts was performed using correlation optimization warping (COW) producing a correlation score of 0.96. To extract the chemically relevant information from the data, a variety of chemometric approaches were employed...
May 29, 2009: Analytica Chimica Acta
https://www.readbyqxmd.com/read/19021167/purity-determination-of-yunaconitine-reference-standard-using-hplc-with-experimental-design-and-response-surface-optimization
#8
Jing-Zheng Song, Chun-Feng Qiao, Song-Lin Li, Quan-Bin Han, Hong-Xi Xu
Experimental design and response surface methodology have been used for the development of the stability-indicating HPLC method for the purity determination of yunaconitine reference standard. Significant factors including the contents of ACN, perchloric acid, triethylamine (TEA), and column temperature were optimized using a Box-Behnken design. A mixture of crude yunaconitine extract and degradation solutions of yunaconitine under stress conditions was chromatogramed. The normalized peak area of total impurities, the retention time of yunaconitine, and the resolutions between yunaconitine and its adjacent peaks were selected as optimization criteria...
December 2008: Journal of Separation Science
https://www.readbyqxmd.com/read/18969068/on-line-screening-methods-for-antioxidants-scavenging-superoxide-anion-radical-and-hydrogen-peroxide-by-liquid-chromatography-with-indirect-chemiluminescence-detection
#9
Toshimasa Toyo'oka, Tomoaki Kashiwazaki, Masaru Kato
The identification of radical species is possible by the electron spin resonance technique. However, the antioxidants in complex matrices such as biological and food samples are difficult to determine. Hence, we developed novel screening systems for antioxidants, which are mainly eliminating superoxide anion radical (O(2)(-)) and hydrogen peroxide (H(2)O(2)), by HPLC with luminol-based chemiluminescence (CL) detection. When the sample contains antioxidants, inhibited peaks corresponding to each antioxidant are observed on the chromatogram...
June 13, 2003: Talanta
https://www.readbyqxmd.com/read/17313099/determination-of-the-interconversion-energy-barrier-of-2-3-pentadienedioic-acid-enantiomers-by-hplc-2-on-column-interconversion
#10
Janka Mydlová, Andrea Fedurcová, Jozef Lehotay, Jan Krupcík, Pavel Májek, Daniel W Armstrong, Brian Lingfeng He, F Albert Cotton
In this paper, an HPLC method is used to determine the enantiomerization barrier of 2,3-pentadienedioic acid enantiomers. The racemate of 2,3-pentadienedioic acid was separated by HPLC on a chiral CHIROBIOTIC T column with a 90:10 (100:0.5:0.5 MeOH/HOAc/TEA)/H2O mobile phase. Peak areas of enantiomers prior to (A(+)0, A(-)0) and after the separation (A(+), A(-)), were used for calculation of the rate constants and the enantiomerization barrier, as determined by computer-assisted peak deconvolution of the peak clusters on the chromatograms...
November 2006: Journal of Separation Science
https://www.readbyqxmd.com/read/16301079/prediction-of-total-green-tea-antioxidant-capacity-from-chromatograms-by-multivariate-modeling
#11
A M van Nederkassel, M Daszykowski, D L Massart, Y Vander Heyden
In this paper, a fast strategy for determining the total antioxidant capacity of Chinese green tea extracts is developed. This strategy includes the use of experimental techniques, such as fast high-performance liquid chromatography (HPLC) on monolithic columns and a spectrophotometric approach to determine the total antioxidant capacity of the extracts. To extract the chemically relevant information from the obtained data, chemometrical approaches are used. Among them there are correlation optimized warping (COW) to align the chromatograms, robust principal component analysis (robust PCA) to detect outliers, and partial least squares (PLS) and uninformative variable elimination partial least squares (UVE-PLS) to construct a reliable multivariate regression model to predict the total antioxidant capacity from the fast chromatograms...
November 25, 2005: Journal of Chromatography. A
https://www.readbyqxmd.com/read/15127826/simultaneous-analysis-of-theanine-chlorogenic-acid-purine-alkaloids-and-catechins-in-tea-samples-with-the-help-of-multi-dimension-information-of-on-line-high-performance-liquid-chromatography-electrospray-mass-spectrometry
#12
Xiaolan Zhu, Bo Chen, Ming Ma, Xubiao Luo, Fei Zhang, Shouzhuo Yao, Zutian Wan, Dajin Yang, Hongwei Hang
A reverse phase high performance liquid chromatography (RP-HPLC) separation coupled with photo diode array detection (DAD) and electrospray ionization mass spectrometry (ESI-MS) detection was established for the analyzing of multiple bioactive compounds in tea and tea extracts. Theanine, chlorogenic acid, purine alkaloids and catechins were identified with authentic standard compounds and with MS-spectra. The content of theanine and catechins was measured by employing DAD and caffeine, chlorogenic acid, theobromine and theopylline by protonated molecular ion on selective ion recording (SIR) mode...
February 18, 2004: Journal of Pharmaceutical and Biomedical Analysis
https://www.readbyqxmd.com/read/11383158/-application-and-improvement-of-aflatoxin-analysis-in-foods-using-a-multifunctional-column-and-hplc
#13
Y Goda, H Akiyama, T Otsuki, A Fujii, M Toyoda
In an earlier report, we developed a rapid, sensitive and clean method consisting of non-chloroform extraction, clean-up on a commercial multifunctional cartridge column and HPLC with fluorescence detection for the analyses of aflatoxins. In this report, we applied this method to analyze aflatoxins in nuts, giant corn, cereals, spice and black teas. The method was effective for macadamia nuts, walnuts, hazelnuts, brazil nuts, giant corn, rice, wheat and buckwheat, and the recoveries of aflatoxins B1, B2, G1 and G2 spiked in them at the level of 10 ng/g were 85-106%...
February 2001: Shokuhin Eiseigaku Zasshi. Journal of the Food Hygienic Society of Japan
https://www.readbyqxmd.com/read/6720080/-types-of-binding-of-iron-copper-and-zinc-in-various-varieties-of-tea
#14
COMPARATIVE STUDY
G Weber, G Schwedt
Extracts of several varieties of tea were separated by HPLC and the resulting substances detected by various techniques with a view to characterizing the fractions of organic metal complexes of copper, zinc, and iron. In addition to uv methods and conductivity measurements particular stress was laid on the application of HPLC coupled with chemical reaction detectors for metals (photometric determination of total content) and for functional groups, such as phenolic OH-, SH-, and NH-groups. The distribution of the different metals was found by coupling HPLC with AAS...
1984: Zeitschrift Für Lebensmittel-Untersuchung und -Forschung
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