Simultaneous determination of caffeine, gallic acid, theanine, (−)-epigallocatechin and (−)-epigallocatechin-3-gallate in green tea using quantitative1H-NMR spectroscopy

2014 ◽  
Vol 6 (3) ◽  
pp. 907-914 ◽  
Author(s):  
Yunfei Yuan ◽  
Yuelin Song ◽  
Wanghui Jing ◽  
Yitao Wang ◽  
Xiaoyun Yang ◽  
...  
Keyword(s):  
Nmr Spectroscopy ◽  
Gallic Acid ◽  
Simultaneous Determination ◽  
Green Tea ◽  
Chemical Characterization ◽  
Tea Polyphenols ◽  
H Nmr

1H-NMR spectroscopy is utilized for chemical characterization along with simultaneous determination of caffeine, gallic acid, theanine and tea polyphenols, in commercial green tea.

1H NMR determination of 1,3-dicyclohexylurea, glutaric acid and triethylamine in medical four-arm poly(ethylene glycol)-N-hydroxysuccinimide-glutarate for better quality control

2019 ◽  
Vol 11 (48) ◽  
pp. 6176-6183 ◽  
Author(s):  
Fei-Fei Li ◽  
Hui-Xiang Liu ◽  
Yan-Li Zhang ◽  
Shu-Qi Wang
Keyword(s):  
Quality Control ◽  
Nmr Spectroscopy ◽  
Ethylene Glycol ◽  
Simultaneous Determination ◽  
Glutaric Acid ◽  
Polymer Materials ◽  
Poly Ethylene Glycol ◽  
H Nmr ◽  
Poly Ethylene

Simultaneous determination of 1,3-dicyclohexylurea, glutaric acid and triethylamine by 1H NMR spectroscopy for established quality control standards for residues in polymer materials.

Simultaneous Determination of Four Herbicide and Pesticide Residues in Chinese Green Tea Using QuEChERS Purification Procedure and UPLC-MS/MS Analysis

2013 ◽  
Vol 634-638 ◽  
pp. 1586-1590
Author(s):  
Su Fang Wang ◽  
Shou Jie Zhang ◽  
Chun Hong Dong ◽  
Guo Qing Wang ◽  
Jun Feng Guo ◽  
...  
Keyword(s):  
Formic Acid ◽  
Simultaneous Determination ◽  
Green Tea ◽  
Limit Of Detection ◽  
Multiple Reaction Monitoring ◽  
Graphitized Carbon Black ◽  
Ms Analysis ◽  
Relative Standard ◽  
Limit Of Quantitation

A method for simultaneous determination of residuals of four herbicides and pesticides, simazine, carboxin, diflubenzuron and rotenone, in Chinese green tea was developed. In the proposed method, the tea powder was placed in a centrifuge tube with a plug, extracted in saturated aqueous sodium chloride solution and acetonitrile, agitated using vortex oscillator, and then centrifuged 5 min at 4000 rpm. The supernatant solution was purified by primary secondary amine (PSA) sorbent, C18 power, and graphitized carbon black powder, respectively. Then the purified extracts were dissolved with acetonitrile:0.1% formic acid aqueous solution (40:60, V/V) and agitated, filtered using a syringe with 0.22 μm nylon filter prior to UPLC-MS/MS analysis. The UPLC analysis was performed on an ACQUITY UPLC® HSS T3 column (2.1 mm×100 mm, 1.8 µm), using acetonitrile-0.1% formic acid as mobile phase with the flow rate as 0.3 mL•min-1. Injection volume was 10 µL. Positive ionization mode was applied, and the ions were monitored in the multiple reaction monitoring (MRM) mode with curtain gas 0.069 MPa, collision gas 0.052 MPa, ESI ion spray voltage 5000 V, temperature 550 °C, nebulizer gas 0.24 MPa, and turbo gas 0.28 MPa. The limit of detection (LOD) and limit of quantitation (LOQ) of the proposed method are 1 μg•kg-1and 5 μg•kg-1, respectively. The average recoveries of the four pesticides at 10, 20, and 50 µg•kg-1spiking levels range from 77.4% to 95.3%. TheSupersSuperscript textcript textrelative standard deviation (RSD) (n=6) range form 11.83% to 4.52%.

scholarly journals HPTLC method for simultaneous determination of ascorbic acid and gallic acid biomarker from freeze dry pomegranate juice and herbal formulation

2019 ◽  
Vol 27 (7) ◽  
pp. 975-980 ◽  
Author(s):  
Prawez Alam ◽  
Y.T. Kamal ◽  
Saleh Ibrahim Alqasoumi ◽  
Ahmed Ibrahim Foudah ◽  
Mohammed Hamed Alqarni ◽  
...  
Keyword(s):  
Ascorbic Acid ◽  
Gallic Acid ◽  
Simultaneous Determination ◽  
Pomegranate Juice ◽  
Herbal Formulation ◽  
Hptlc Method

Determination of the content of fatty acid methyl esters (FAME) in biodiesel samples obtained by esterification using 1 H-NMR spectroscopy

2008 ◽  
Vol 46 (11) ◽  
pp. 1051-1054 ◽  
Author(s):  
Vinicius M. Mello ◽  
Flavia C. C. Oliveira ◽  
William G. Fraga ◽  
Claudia J. do Nascimento ◽  
Paulo A. Z. Suarez
Keyword(s):  
Fatty Acid ◽  
Nmr Spectroscopy ◽  
Fatty Acid Methyl Esters ◽  
Methyl Esters ◽  
H Nmr ◽  
Acid Methyl
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