DDTs in soil were extracted with acetone/hexane (1:1, v/v) using ultrasonic extraction and removed many polar matrix components using primary secondary amine (PSA) effectively for the purity.

• 样品用丙酮/正己烷(1:1,v/v)超声波提取,然后用固相材料吸附净化,用GC-MS(选择离子方式)测定。