提出了顶空-气相色谱-质谱法测定土壤中甲胺、乙胺、二甲胺、二乙胺、三甲胺、三乙胺等6种有机胺含量的方法。土壤样品在顶空瓶中经盐酸溶液提取,加入一定量的氢氧化钠溶液、氨水,然后在顶空进样器中于80℃平衡30 min,使气液两相达到动态平衡。采用CP-Volamine色谱柱对目标物进行分离,质谱仪检测,外标法定量。结果显示:6种有机胺的质量浓度在一定范围内与其对应峰面积呈线性关系,检出限(3.143s)为0.000 33~0.18 mg·kg^-1;混合标准溶液中6种有机胺测定值的相对标准偏差(n=6)为2.3%~4.7%;对空白样品进行3个浓度水平的加标回收试验,回收率为80.0%~108%;方法用于5种不同类型实际土壤样品分析,两种土壤样品中检出三乙胺,检出量为11.3,391 mg·kg^-1。

A method for the simultaneous determination of 6 organic amines including methylamine, ethylamine, dimethylamine, diethylamine, trimethylamine and triethylamine in soil by gas chromatography-mass spectrometry after headspace was proposed. The soil sample was extracted with hydrochloric acid solution in headspace bottle, and a certain amount of sodium hydroxide solution and aqueous ammonia was added, and then equilibrated at 80℃ for 30 min in headspace sampler to make the dynamic equilibrium between gas phase and liquid phase. The target compounds were separated on CP-Volamine chromatographic column, detected by mass spectrometer, and quantified by external standard method. It was shown that linear relationships between values of mass concentration and peak area of 6 organic amines were kept in the definite ranges, with detection limits (3.143s) in the range of 0.000 33-0.18 mg·kg^-1, and RSDs (n=6) of the determined values of 6 organic amines in the mixed standard solutions were ranged from 2.3% to 4.7%. Test for recovery was made on the blank sample at 3 concentration levels by standard addition method, giving results in the range of 80.0%-108%. This method was applied to analysis of the actual samples, the detection amount of triethylamine was 11.3, 391 mg·kg^-1 in two soil samples.