Dissipation and residues of nicosulfuron in corn and soil under field conditions.

A simple, sensitive method for the analysis of nicosulfuron in corn and soil was developed. Samples were extracted with acetonitrile: water (2:3, V/V) mixture and partitioned with dichloromethane. After concentration, the soil sample extracts were detected using high performance liquid chromatography-ultraviolet detector (HPLC-UVD), and the corn sample extracts were detected using high performance liquid chromatography-mass spectrometry detector (HPLC-MSD). The fortified recoveries at 0.05-1.0 mg/kg were 79.7%-115.8%, with the relative standard deviation of 1.40%-13.8%. The limit of detection of the analytical method was 0.05 ng at a signal-to-noise ratio of 3, and the limit of quantification was 0.05 mg/kg for both corn and soil. The dissipation dynamics of nicosulfuron in the field trials in Beijing and Changchun were investigated. The half-lives of nicosulfuron in corn plants were 0.73 days in Beijing and 0.53 days in Changchun, both with a dissipation rate of 90% over 7 days after application. The half-lives in soil were 13.64 days both in Beijing and in Changchun with a dissipation rate of 90% over 21 days. Low residues and short half-life in corn suggested that nicosulfuron could be safely used in corn crops with the suitable dosage and application.