顶空固相微萃取-气相色谱法测定地表水中15种硝基苯类化合物

Determination of 15 Nitrobenzenes in Surface Water by Headspace Solid-phase Microextraction-gas Chromatography

建立了顶空固相微萃取(HS-SPME)-气相色谱法(GC-ECD)测定地表水中15种硝基苯类的分析方法。优化了萃取纤维头、萃取温度、萃取时间、搅拌速度、离子强度、pH值以及解吸温度等参数。结果表明:采用PA(85μm)纤维头可获得相对较高的回收率,水样分析前可加入NaCl固体至饱和,于70℃下萃取30 min,萃取过程中以300 r/min的速度进行搅拌,萃取结束后,260℃下解吸3 min。在该优化参数下,15种硝基苯类化合物在1.0~50μg/L范围内线性关系良好,相关系数均大于0.999,方法检出限在0.02~0.12μg/L之间,加标回收率为72.5%~112.4%,日内与日间精密度均小于10%。该方法简便、灵敏、准确度高、稳定性好,能够满足地表水检测的要求。

A method based on headspace solid-phase microextraction（HS/SPME） with gas chromatography/electron capture detector（ECD） was developed for the determination of 15 nitrobenzenes in surface water. Parameters of the extraction conditions were optimized, such as SPME fiber, extraction temperature, extraction time, desorption temperature, pH and ionic strength. The results showed that better recoveries were obtained with the PA fiber（85 μm）. NaCl solid was added into the water sample before extraction. The extraction was processed under 70 ℃ and lasted for 30 min. The stirring speed was 300 r/min. The adsorption temperature was 260 ℃ and lasted for 3 min. The linear range for the 15 nitrobenzenes was 1.0 ~ 50.0 μg/L with the correlation coefficient higher than 0.999. The method detection limits were in the range of 0.02 ~ 0.12 μg/L. The recoveries for the actual water and distrilled water were 72.5% ~ 112.4%, with relative standard deviations lower than 10%（n = 7）. The developed method is simple, sensitive, accurate and reproducible. It is suitable for the routine monitoring of trace amount of nitrobenzenes in the surface water.