Herbicide quinclorac analysis in paddy soil samples by solid-phase extraction and high performance liquid chromatography

Quinclorac is one of the main herbicides used in paddy fields in China.Quinclorac residues in paddy soil may significantly influence the growth of sensitive crops such as tobacco.An analytical method employing high performance liquid chromatography(HPLC)with a diode array detector(DAD)was developed to determine quinclorac residues in paddy soil samples.Quinclorac was extracted from paddy soil samples by 5% ammonia methanol solution(v/v)and cleancd up by solid-phase extraction(SPE)with Bond Elute SAX cartridge.Recoveries of quinclorac at 0.005-1.000 μg·g^-1 were 82.36%-l06.30%,with relative standard deviations(RSDs)of 2.45%-6.83%.The limit of detection(LOD)was 0.001 μg·g^-1 at a signal-to-noise ratio of 3,and the limit of quantification(LOQ)was 0.005 μg·g^-1 The same quinclorac residue samples were further analyzed and confirmed by ultra-performance liquid chromatography-tandem mass spectrometry(UPLC-MS/MS).The proposed method was successfully applied to the analysis of quinclorac residues from the paddy fields with previous quinclorac treatment in Jiangxi Province.