Optimal extraction conditions for simultaneous determination of catechins and caffeine in green tea leaves

2011 ◽  
Vol 20 (2) ◽  
pp. 327-333 ◽  
Author(s):  
Myoung-Gun Choung ◽  
Min-Seuk Lee
Keyword(s):  
Simultaneous Determination ◽  
Green Tea ◽  
Tea Leaves ◽  
Green Tea Leaves

scholarly journals Determination of chlorothalonil residues in raw tea and green tea leaves by an enzyme-linked immunosorbent assay

2008 ◽  
Vol 33 (4) ◽  
pp. 387-392
Author(s):  
Eriko Hatakeyama ◽  
Hiroko Kajita ◽  
Takashi Sugawara ◽  
Satoru Takahashi
Keyword(s):  
Green Tea ◽  
Immunosorbent Assay ◽  
Enzyme Linked Immunosorbent Assay ◽  
Tea Leaves ◽  
Green Tea Leaves

Determination of Pyrethroid Residues in Vegetables, Fruits, Grains, Beans, and Green Tea Leaves: Applications to Pyrethroid Residue Monitoring Studies

1993 ◽  
Vol 76 (6) ◽  
pp. 1348-1361 ◽  
Author(s):  
Yumiko Nakamura ◽  
Yasuhide Tonogai ◽  
Yukari Tsumura ◽  
Yoshio Ito
Keyword(s):  
Green Tea ◽  
Fused Silica ◽  
Electron Capture Detection ◽  
Synthetic Pyrethroids ◽  
Methyl Silicone ◽  
Tea Leaves ◽  
Florisil Column ◽  
Fused Silica Capillary ◽  
Green Tea Leaves

Abstract Determination of natural pyrethrins and 12 synthetic pyrethroids in agricultural products was investigated. Vegetables and fruits were extracted with acetone, filtered after addition of coagulating solution, partitioned into n-hexane, and cleaned up on a Florisil column (as necessary). Pyrethroids were determined by gas chromatography/electron capture detection (GC/ECD) by using a methyl silicone-coated fused-silica capillary column, and recoveries were calculated by summing peak areas of the components. GC/mass spectrometry was used to identify the pyrethroids detected by GC/ECD monitoring. Grains and beans containing lipids were analyzed by extraction with acetonitrile, partition into n-hexane, Florisil column cleanup, and capillary GC/ECD. The coagulation method was suitable for nonfatty crops such as vegetables, fruits, and green tea leaves, because recoveries were good and Florisil column cleanup was not needed in most cases. The coagulation method was not applicable to lipid-containing crops such as grains and beans because of low recoveries. Recoveries for 18 crops at fortification levels of 0.25–1.0 ppm were 60.0–103.5%. No pyrethroids were detected from the nonfortified crops tested except green tea leaves, in which fluvalinate was detected at 0.89 ppm.

Effects of Soil Selenium Supplementation Level on Selenium Contents of Green Tea Leaves and Milk Vetch

2007 ◽  
Vol 12 (1) ◽  
pp. 35-39 ◽  
Author(s):  
Dae-Jin Kim ◽  
Dae-Soo Chung ◽  
Sung-Chul C. Bai ◽  
Hyeong-Soo Kim ◽  
Yu-Bang Lee
Keyword(s):  
Green Tea ◽  
Selenium Supplementation ◽  
Tea Leaves ◽  
Green Tea Leaves
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