顶空气相色谱法测定土壤中有机溶剂残留量

Determination of soil residual organic solvents content by headspace gas chromatography

以HP-INNOWAX色谱柱(30 m×0.32 mm×0.25μm)为分离柱,火焰离子化检验,外标法定量,考察顶空平衡温度、平衡时间对土壤中有机溶剂残留量测定结果的影响。建立了土壤中正己烷、乙酸乙酯、丙酮、甲醇等有机溶剂残留量的顶空气相色谱分析方法。实验结果表明,在顶空平衡温度为90℃,平衡时间为30 min条件下获得较好的定量结果。正己烷的线性方程为Y=11.49X-4.806、乙酸乙酯为Y=4.997X-2.873、丙酮为Y=9.710X-1.556、甲醇为Y=9.316X-5.956;平均回收率范围为78%~97%,精密度(以相对标准偏差计,n=6)为2.8%~9.4%,检出限分别为0.9、0.2、0.6 mg/L和0.4 mg/L。利用该方法对实际样品土壤中有机溶剂残留量进行了检测。结果表明,该样品中含有正己烷和甲醇,其含量分别为1.9 mg/L和1.1 mg/L。本方法快速、灵敏、准确,适用于土壤中残留溶剂的检测。

A method for the determination of four kinds of soil residual organic solvents was developed by headspace gas chromatography. An HP-INNOWAX column（30 m × 0. 32 mm × 0. 25 μm）,a flame ionization detector and the external standard method were used for the separation and quantitative analysis. The effects of equilibrium temperature and equilibrium time on the determination of residual organic solvents were investigated. The better results were observed in the equilibrium temperature of 90℃ and equilibrium time of 30 min. The standard curves were： Y = 11. 49 X-4. 806 for hexane,Y = 4. 997 X-2.873 for ethyl acetate,Y = 9. 710 X-1. 556 for actone,and Y = 9. 316 X-5. 956 for methanol. The average recoveriy range for the four residual organic solvents were between 78% ～ 97% and with relative standard deviations（ RSDs）（ n = 6） of 2. 8% ～9. 4%. The detection limits of actone,methanol,hexane,and ethyl acetate were 0. 9,0. 2,0. 6 mg/L and 0. 4 mg/L,respectively. The proposed method was successfully applied to analyze the residue organic solvents in sampled soil. The results showed that hexane and methanol were found in the sample with the contents of 1. 9 mg/L and 1. 1 mg/L,respectively. The method is rapid,sensitive and accurate for the content determination of residual solvents in soil.