Residue analysis and security judgement of parathion-methyl and parathion residues in tea

Abstract

Objective： To detect the level of parathion-methyl and parathion residues in different types of tea by high pressure liquid chromatography coupled with matrix solid phase dispersion. Methods： Before determined by high pressure liquid chromatography （HPLC）, the tea samples were pretreated by matrix solid phase dispersion method grinding with neutral alumina as dispersant and eluting by ethyl acetate: n-hexane （8%）. Results： The results showed that this method was simple, rapid and accurate, with good linearity （0.999 6 for parathion-methyl and 0.999 5 for parathion）, low detection limits （0.015, 0.006 mg/kg, respectively） and high recoveries （90.67% and 86.67%, respectively）. Incidence of parathion-methyl and parathion occurred with a frequency of 7.69% and 19.23%, and the average concentration of 0.004 8 mg/kg and 0.008 5 mg/kg, respectively. The residue levels varied from tea types. The corresponding average daily intake of parathion-methyl and parathion by drinking was 0.023 6 and 0.104 1 μg/（kg·d·BW）, respectively. Conclusion： The problem of methyl parathion and parathion residues in different tea samples was not prominent, and their residues did not exceed the standard. The detection probability and residue of parathion were higher than those of methyl parathion. The probability of parathion detection in oolong tea, black tea and green tea was higher, but the analysis data showed that there was no health risk problem caused by drinking tea for general consumers.

Keywords

• parathion
• parathion-methyl
• residues analysis
• tea
• health risk assessment