尿中甲基异丁基酮测定的顶空-气相色谱/质谱法

Determination of methyl isobutyl ketone in urine by headspace coupled with gas chromatography-mass spectrometry

目的建立顶空-气相色谱/质谱法测定尿液中甲基异丁基酮(MIBK)。方法采用自动顶空进样技术,通过对顶空条件(顶空瓶加热温度、平衡时间)和气相色谱条件进行优化,取5 ml样品于20 ml顶空瓶中,加3.0 g硫酸铵,经60℃加热30 min后,吸取100μl顶空瓶上部气体,注入气相色谱经HP-5MS UI(30 m×0.25 mm×0.25μm)毛细管柱分离,质谱检测器检测,保留时间定性,外标法定量检测样品中MIBK含量。结果本方法测定MIBK的线性范围为20.0~1000.0μg/L,线性方程为y=62.9x-652.5,相关系数r=0.9998。方法检出限为5.0μg/L,定量下限为16.0μg/L。在低(50.0μg/L)、中(200.0μg/L)、高(500.0μg/L)三个添加浓度下,样品加标回收率为95.3%~100.2%;批内精密度为1.7%~3.8%(n=6),批间精密度为1.2%~4.0%(n=6)。该方法测定尿液中MIBK稳定性良好,样本在-20℃及以下冰箱至少可以保存14 d。结论本法简单实用,重现性好,灵敏度高,可应用于MIBK职业接触人群的生物检测。

Objective To establish a method for the determination of methyl isobutyl ketone(MIBK)in urine samples by headspace-gas chromatography-mass spectrometry.Methods Automatic headspace sampling technique was adopted to optimize the headspace conditions(headspace bottle heating temperature and equilibration time)and gas chromatographic conditions.A total of 5 ml samples were taken and added with 3.0 g ammonium sulfate into a 20 ml headspace bottle.After heated at 60℃for 30 mins,gas from the upper part of headspace bottle was injected into gas chromatography with an injection volume of 100μl.The target was separated by HP-5MS UI(30 m×0.25 mm×0.25μm)capillary column and then detected by mass spectrometry detector.The retention time and external standard method were used for qualitative and quantitative analysis of MIBK in samples,respectively.Results The standard curve of MIBK showed significant linearity between 20.0-1000.0μg/L.The standard curve was y=62.9x-652.5,and the correlation coefficient r=0.9998.The detection limit of MIBK was 5.0μg/L and the quantification limit of MIBK was 16.0μg/L.The average recovery rate was 95.3%~100.2%at three spiked concentrations of low(50.0μg/L),medium(200.0μg/L)and high(500.0μg/L).The intra-day and inter-day precisions were 1.7%~3.8%(n=6)and 1.2%~4.0%(n=6)respectively.This method was stable for the determination of MIBK,and the urine could be kept 14 d at-20℃without significantly loss.Conclusion This method is proved to be simple,practical and highly sensitive.It can satisfy the request for the determination of urine samples of workers exposed to MIBK.