Study on the photodegradation and microbiological degradation of pirimicarb insecticide by using liquid chromatography coupled with ion-trap mass spectrometry.

The intermediates of photodegradation and microbial degradation of pirimicarb insecticide were investigated by liquid chromatography coupled with ion-trap mass spectrometry (LC-IT-MS). Different intermediates were detected in the photodegradation and microbial degradation of pirimicarb. In the photodegradation of pirimicarb in aqueous solution 2-dimethylamino-5,6-dimethyl-4-hydroxypyrimidine (MW=167), 2-methylamino-5,6-dimethylpyrimidin-4-yl-dimethylcarbamate (MW=224) and 2-formylamino-5,6-dimethylpyrimidin-4-yl-dimethylcarbamate (MW=252) were the main products. It was found that 2-dimethylamino-5,6-dimethyl-4-hydroxypyrimidine (MW=167) was the major product in the microbial degradation of pirimicarb in soil.