A Method on Residue Analysis of Polyoxin in Paddy Soil and Water

KeyWord:polyoxin  paddy soil  paddy water  high performance liquid chromatography(HPLC)  residue analysis

Abstract:

      A high performance liquid chromatography(HPLC) method was developed for the determination of polyoxin residue in paddy soil and water. The paddy water was adjusted to pH 8.0 with ammonia water£¬and extracted with acetic ether to remove organic impurities. The water phase was concentrated to constant. The paddy soil was extracted using alkaline mixed with solution of carbinol-water(70¡Ã30)£¬and concentrated to constant. The above extracts were separated on a C18 hydrophilic stainless steel chromatographic column(AQ-C18,4.6 mm¡Á250 mm,5 ¦Ìm) and detected with ultraviolet detector(UVD).The quantification analysis of polyoxin was performed by the external standard.The other optimal conditions were as follows:mobile phase:carbinol- water(13¡Ã87);flow rate:1.0 mL/min for first 0-8 min£¬and 0.3 mL/min for the next 8-16 min£¬column temperature:30 ¡æ£¬detection wavelength:272 nm. Under the optimal conditions£¬the calibration curve was linear between peak area and polyoxin concentration in the range of 0.05-2.00 mg/L with correlation coefficient of 0.998 8.The limit for detection for polyoxin was 1.0¡Á10-9 g£¬and the detection limits of polyoxin in paddy soil and water were 0.05 mg/kg and 0.05 mg/L£¬respectively.The spiked recoveries of polyoxin in paddy water and soil at spiked concentrations of 0.06,0.60,1.00 mg/kg were in the range of 97%-99% and 95%-97%,with RSDs of 0.71%-2.4% and 1.7%-4.5%£¬respectively.This method showed the advantages of easy operation£¬good separation effect and high accuracy£¬and could meet the requirements for pesticide residue detection.