Determination of formic acid in urine by automatic headspace-gas chromatography-mass spectrometry

Abstract

Objective To establish a method for the determination of formic acid in urine by automatic headspace-gas chromatography-mass spectrometry.

Methods The urine sample was added with 3 mL 15.00% ( V/V) sulfuric acid ethanol and heated in an automatic headspace sampler. The formic acid and ethanol underwent an esterification reaction to produce ethylformate which was separated by gas chromatographic column and detected by mass spectrometer. The quantification was based on external standard method.

Results The linear range of the method was 2.93–97.60 mg/L, with the regression equation correlation coefficient of 0.999 5. The detection limit was 0.65 mg/L and the minimum quantitative limit was 2.17 mg/L, with the recoveries of 95.61 %-106.47%. The within-run relative standard deviation ( RSD) ranged from 2.52% to 8.05% and the between-run RSD ranged from 6.58% to 8.42%.

Conclusion The method has simple pretreatment, good specificity, high precision and has little interference. It is suitable for large scale rapid determination of formic acid in urine in occupational contact population, patients with acute methanol poisoning and general population.

Abstract

摘要： 目的 建立自动顶空-气相色谱-质谱(GC-MS)联用法测定尿中甲酸。 方法 取 3 mL尿样加人 3 mL体积分数 为15.00%的硫酸乙醇溶液, 样品在自动顶空进样器中加热, 甲酸与乙醇在80 °C下发生酯化反应, 生成的甲酸乙酯经气相 色谱分离, 质谱检测, 外标法定量。 结果 本方法在2.93~97.60 mg/L内线性相关系数为0.999 5; 方法检出限为0.65 mg/L,定量下限为2.17 mg/L;加标回收率为95.61%~106.47% ;批内相对标准偏差( RSD)为2.52%~8.05%, 批间 RSD为6.58%~8.42%。 结论 自动顶空-GC-MS联用法前处理简单, 特异性好, 精密度高, 干扰少, 可用于职业接触人 群、急性甲醇中毒患者和普通人群尿液甲酸水平的大批量快速测定。