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通过对样品前处理方法和气相色谱条件的改进,建立一套稳定的沉积物中六氯环己烷、双对氯苯基三氯乙烷残留的气相色谱检测方法,满足实验室批量测定样品的要求。选择40 mL正己烷和丙酮混合液(V正己烷∶V丙酮=1∶1)作为提取液,并加入2 g铜粉去除硫化物,用Florisil SPE小柱和Carbon-GCB SPE小柱串联净化,采用10mL正己烷和丙酮混合液(V正己烷∶V丙酮=9∶1)进行洗脱,浓缩后用DB-1701气相毛细管柱分离,用带电子捕获检测器的气相色谱仪(GC-ECD)检测,外标法定量。本研究选择沙质性状的沉积物作为基准进行加标回收实验,平均回收率在74.5%～92.0%,相对标准偏差在3.09%～6.67%;检出限为α-HCH:1.96×10-4 mg/kg,β-HCH:1.45×10-6 mg/kg,γ-HCH:1.90×10-4 mg/kg,δ-HCH:1.98×10-4 mg/kg,p,p’-DDD:2.47×10-6 mg/kg,o,p’-DDT:1.08×10-4mg/kg,p,p’-DDE:1.59×10-4 mg/kg,p,p’-DDT:2.52×10-4 mg/kg。采用泥质性状的沉积物对本方法进行验证,加标回收率和相对标准偏差都符合沉积物样品的药残检测要求。研究亮点:采用固相萃取-气相色谱法测定沉积物中六氯环己烷、双对氯苯基三氯乙烷的残留量,溶剂用量少,操作步骤简单,与同类方法相比较,该方法大大提高实验室批量样品的检测效率。本方法净化效果好,灵敏度高,样品加标回收率达到70%以上,相对标准偏差小于10%,且重现性好,符合沉积物样品的药残检测要求。
Through the improvement of the sample pretreatment method and the gas chromatographic conditions, a set of stable gas chromatography detection methods for the determination of hexachlorocyclohexane and bis-p-chlorophenyltrichloroethane in the sediment was established to meet the needs of laboratory batch determination of Claim. Choose 40 mL n-hexane and acetone mixture (V n-hexane: V acetone = 1: 1) as an extract, and add 2 g of copper powder to remove sulfides. Clean them in series with a Florisil SPE cartridge and a Carbon- The mixture was eluted with 10 mL of a mixture of n-hexane and acetone (V-n-hexane: V acetone = 9: 1), concentrated and separated on a DB-1701 capillary gas chromatograph using a gas chromatograph with an electron capture detector (GC- Testing, external standard method. In this study, sand sediments were selected as the standard spiked recoveries. The average recoveries ranged from 74.5% to 92.0% and the relative standard deviations ranged from 3.09% to 6.67%. The detection limit was α-HCH: 1.96 × 10-4 β-HCH: 1.45 × 10-6 mg / kg, γ-HCH: 1.90 × 10-4 mg / kg, δ-HCH: 1.98 × 10-4 mg / kg, p, p’-DDD: 2.47 × 10-6 mg / kg, o, p’-DDT: 1.08 × 10-4 mg / kg, p, p’-DDE: 1.59 × 10-4 mg / -4 mg / kg. The method was verified by using muddy sediments. The spiked recoveries and relative standard deviations (RSDs) of the samples were in accordance with the requirements of drug residue detection of sediment samples. Research highlights: Determination of residual hexachlorocyclohexane and bis-p-chlorophenyltrichloroethane in sediments by solid-phase extraction-gas chromatography with less solvent consumption and simple procedure, compared with similar methods The method greatly improves the efficiency of the laboratory batch sample detection. The method has the advantages of good purification effect and high sensitivity, the recovery rate of spiked samples reaches above 70%, the relative standard deviation is less than 10%, and the reproducibility is good, which meets the requirements of drug residue detection of sediment samples.