超声辅助提取-固相萃取净化-高效液相色谱法测定沉积物中的2甲4氯残留

目的]2甲4氯(MCPA)是农业生产和市政管理中一种广泛使用的除草剂,具有使用量大、生物毒性强、易迁移累积于水体沉积物等特点。针对其在沉积物中潜在环境风险大的现状,一种简单、有效的残留测定方法迫切需要建立。方法]建立了一种C18为分离色谱柱,甲醇-水(体积比80:20)为流动相,PDA为检测器,检测波长为280 nm的MCPA高效液相检测法,并比较了不同提取方法和净化方法对检测的影响。结果]对于提取方法,回收率:超声萃取2次>超声萃取1次>涡旋振荡萃取;对于净化方法,回收率:固相萃取净化法>QuEChERS法>未净化法。因此,应采用2次超声辅助提取-固相萃取净化作为前处理方法。所建立的方法在0.5~40 mg/L范围内线性良好,检出限为0.02 mg/kg,定量限为0.06 mg/kg;在0.08~0.8 mg/kg的添加水平范围内,回收率为85.12%~98.66%,相对标准偏差为2.86%~4.24%。结论]该方法准确性高、稳定性好,适用于沉积物中MCPA的测定。

Determination of 4-Chloro-2-methylphenoxyacetic Acid in Sediment by HPLC with Ultrasound-assisted Extraction and Solid Phase Extraction

Aims]4-Chloro-2-methylphenoxyacetic acid(MCPA)is a widely used herbicide in agricultural production and municipal administration with disadvantages of large usage and high biological toxicity,and easy to migrate and accumulate in sediment.Thus,it is urgently needed to develop a simple and effective residue determination method to evaluate the potential environmental risks of MCPA in sediment.Methods]A simple and sensitive high performance liquid chromatographic method for the analysis of MCPA was developed with C18 column,PDA detector set at 280 nm,and a mobile phase consisting of a mixture of 80:20(by vol)methanol and distilled water.Moreover,the effects of different extraction and purification methods were compared.Results]As observed during investigation,the recovery of diverse extraction methods followed an order:twice ultrasonic extraction>one ultrasonic extraction>vortex extraction;the various purification method showed different recovery in an order:solid phase extraction purification>QuEChERS treatment>unpurged treatment.Therefore,a method with twice ultrasonic assisted extraction and solid phase extraction purification should be adopted to pretreat the sediment sample for further analysis of MCPA.Furthermore,to proceed the methodological analysis,good linear relationships between HPLC peak area and concentration for MCPA was optimized from 0.5 to 40 mg/L.Detection limits(LOD)and quantitation Limit(LOQ)were sensitively reached 0.02 and 0.06 mg/kg,respectively.Satisfactory relative recoveries ranging from 85.12 to 98.66% were achieved with relative standard deviations of 2.86-4.24%under the fortified level of 0.08-0.8 mg/kg MCPA.Conclusions]The established method is suitable to detect the residue of MCPA in sediments.