Multi-Residue Analysis of Pesticides in Green Tea Using Caffeine Removal Pretreatment

Introduction

Green tea is becoming a popular beverage worldwide. Table 1-1 through Table 1-3 show the survey results for worldwide green tea production, and import and export quantities. With about 4 million tons produced worldwide, which is about half that of coffee bean production, China boasts the greatest rate of green tea production, followed by India, Kenya and Sri Lanka. Sri Lanka is the greatest exporter of green tea, followed by Kenya, India and China. Domestic consumption is very high in India and China, with about 80 % of the production consumed in those countries. Japan also is a high-producing country, but due to even higher consumption, Japan also imports an amount which is equivalent to 50 % of its own production level. The 27 European Union (EU) countries are the greatest importers, followed by the Russian Federation and the United Kingdom, with very high consumption clearly occurring in Europe. Due to recent concern regarding food safety among consumers, advances in analytical methods for detecting and quantifying pesticide residues now permit the inspection of many crops for the presence of residual pesticides. With an increasing number of pesticides becoming subject to inspection every year, mass spectrometers are the instrument of choice for conducting simultaneous analyses targeting multiple pesticide residues. The multi-residue analysis of pesticides in teas has become common worldwide. Caffeine, which is typically present in large quantities, can interfere with detection and quantitation of pesticides and other tea constituents, and is also a source of contamination in analytical instrumentation. The development of an analytical method for multi-residue analysis of pesticides in green tea by gas chromatography with mass spectrometry (GCMS) is reported in this Application Note. A novel technique was employed to easily and efficiently eliminate caffeine to avoid any adverse effect on pesticide recoveries.

November 2, 2012 GMT