超临界CO_2萃取-气相色谱法检测生菜中有机氯农残

Determination of organochlorine pesticide residues in lettuce by supercritical CO_2 extraction-gas chromatography

采取超临界CO_2萃取生菜中的有机氯农残作为前处理方法,以萃取压力、萃取温度、萃取流量及萃取时间为考察因素,八种有机氯农残的回收率作为考察指标,通过正交实验优化工艺条件,并用气相色谱法对有机氯农残含量进行测定。结果表明,在30 MPa萃取压力、50℃萃取温度下,采用1.5 m L/min的萃取流量萃取20 min,各农残回收率达到最大值,并且其回收率均能达到80%以上。本实验优选的工艺条件适用于生菜中有机氯农残的前处理,较国标方法更加方便快捷。

The organochlorine pesticide residues in lettuce were extracted using supercritical COs as pretreatment method.The extraction conditions were optimized by orthogonal experiments with the pressure,temperature, flow, time as influencing factors and recovery rate as the evaluation index. Gas chromatography was applied to determine the content of organochlorine pesticide residues.The results showed that the recovery of each pesticide residues reached maximum when the extraction pressure was 30 MPa,the temperature was 50 ℃ and the flow rate was 1.5 mL/min, extraction time was 20 min, and the recovery rate was higher than 80%.The optimum conditions of this experiment was suitable for pretreatment of organochlorine pesticide residues in lettuce,and this method was more convenient and quick, compared with the national standard method.