Determina Tion Of 8 Organophosphorous Pesticides In Tea Drinks And Water By SPME-GC

In recent years, there was more attention be paid in the pesticide residues in food and environment. Therefore the maximum limit levels for pesticide residues in foods, especially organophosphorous pesticides(OPPs), became more and more low. The typical methods to analysize pesticides residues usually have many operation steps, much organic solvent and long time. In other hands, the present rapid methods usually could not up to the MRLs. Developing a fast simple, environment friendly method to detetect pesticides in samples is very necessaty.The consumption of tea drink increased year by year, however, there is no available methods for pesticides residues in tea drink. In this study, a new method based on simple pre-treatment technology——solid-phase microextracton (SPME), combined GC-FPD were set up that measures 8 organophosphorous pesticides in tea drinks and water.Firstly, the optimized conditions of SPME extraction in tea drink, include the matrix selection, were investigated. A fast headspace SPME (HS-SPME) method for determination of pesticides residues in tea drinks was established. Its pretreatment is following:10mL total sample solution with 35%NaCl, using 100μm PDMS to extract for 30min with rapid stirring at 70℃as headspace mode. The linear range of the method was 0.1-5μg L-1 and the correlation coefficient(R2)were 0.9926～0.9981. The RSD% at the 0.2μg L-1 were between 12.40% and 24.20%. The limits of detection (LODs) were 69.7ng L-1,36.0ng L-1,3.1ng L-1,14.8ng L-1,13.6ng L-1.And the limits of quantitation (LOQs) were 232.3ng L-1,120.1ng L-1,10.3ng L-1,49.3ng L-1,45.4ng L-1. The recovery rates of two spiked levels (0.2μg L-1 and 1μg L-1) for 7 samples were in the range of 70% to 120%. Chlorpyrifos were detected in all 7 tea drinks and in the among of 0.005-0.023μg L-1, and lower than any MRLs.Then the similar method was established for water sample. The optimized conditions were following:inserting 65μm PDMS/DVB fibre into 10ml water sample contaming 15%NaCl, to extract 30min with rapid stirring at 50℃. The correlation coefficient( R2)were 0.9706-0.9980 for stardard cure, and RSD were 6.60%-23.84%. The LODs and LOQs were 11ng L-1,37ng L-1, responsible. The recovery rate of two spiked levels (0.2μg L-1 and 4μg L-1) were the range of 70% to 120%, and match the standard for pesticide residues analysis. This method has two simple step for extraction without expensive equipment, less time (35min per sample), without organic solvent or toxic drugs, lower LODs(～ng kg-1). In all, it was a simple, rapid, safe, effective method to analysize OPPs in tea drinks and water samples.