Residue Analysis of Octadecyltrimethylammonium Chloride in Soil

Octadecyltrimethylammonium chloride (OTAC) is the active ingredient of Lüqingling,mainly used as orange miticide.The indirect photometric chromatographic method for determination of OTAC was established.And the chromatography condition was optimized:ODS column,water (with 2.5 mmol/L SAA)=25∶ 75 as mobile phase,flow rate at 0.3 mL/min,column temperature at 38 ℃ and the detection wavelength at 294 nm. The detection limit was 1.968×10-9 g and the linear correlation coefficient was 0.998 9. According to the recommended concentration of 66.7 mg/L,the residual amount was from LOD to 4.157 mg/kg. Thirty days after the application,no residue was detected in the soil.