Organophosphate pesticides residue in solution were detected and quantified by high performance liquid chromatography
(Chen et al. 2011) (LC-10A, Shimadzu) with a5-lm reversed phase C18 column (150 mm 9 4.6 mm) and detected with a diode array UV detector, SPD-M10 Avp.Acidified ultrapure water with 0.5 % acetic acid and methanol were used as the mobile phases at a flow rate of 0.8 mL/min, with the volume ratio of acidifying ultrapure water and methanol at 40:60 for dichlorvos, and 60:40 for dimethoate. The detecting wavelength of dichlorvos and dimethoate were both set at k = 220nm and the injection volume was 10 lL. The limit of quantification of this method was 0.05 mg/L for dimethoate and 0.07 mg/L for dichlorvos. The quantification of pesticides was performed using standard curve method, and each sample was injected
twice during HPLC analysis to monitor the reproducibility. The degradation efficiency was described with the remaining fraction g, which was calculated by the following equation.
where C0 is the initial concentration of pesticide prior to DBD treatment and Ct is the remaining concentration at a given treatment time.