单滴微萃取-气相色谱-质谱联用测定水中的硝基咪唑类药物

建立了单滴液相微萃取(SDME)与气相色谱-质谱(GC-MS)联用技术快速检测水中的硝基咪唑类药物,对影响萃取的因素(溶剂的种类及用量、萃取时间、萃取温度及搅拌子的搅拌速度)进行优化。优化的萃取条件为:溶剂为2.5μL正辛醇,温度为50℃,搅拌速度为600 r/min,时间为20 min。萃取后,微液滴转移至衍生化试管,于70℃水浴中衍生45 min,进样分析。该方法在水中的线性范围为0.5~400μg/L,线性相关系数良好(r0.998),检测限为0.16~0.57μg/L。加标自来水和湖水中的相对平均回收率为80.9%~103.6%,相对标准偏差为1.7%~9.0%。

Determination of nitroimidazoles in water samples by gas chromatography-mass spectrometry with single-drop microextraction

In this paper, an immersed single-drop microextraction technique in conjunction with gas chromatography-mass spectrometry was successfully developed for the determination of nitroimidazoles in water. Some important factors (nature of organic solvents, microdrop volume, extraction time and stirring rate) affecting extraction efficiency were investigated and optimized separately n-octyl alcohol microdrop volume of 2.5 μL, temperature of 50 ℃, extraction time of 20 min, a stirring rate of 600 r/min]. After extraction, the microdrop was derivated at about 70 ℃ for 45 min and introduced directly into a gas chromatography-mass spectrometer (GC-MS) injection port for analysis. The limits of detection (LOD) in water for the four studied compounds were between 0.16 and 0.57 ng/mL. The linearity of the method was in the range of 0.5～400 ng/mL with a good correlation coefficient (r>0.998). The tap and lake water samples were successfully analyzed by using the proposed method, but none of the analytes in natural water were detected. The recoveries for the spiked water samples were from 80.9% to 103.6% with the relative standard deviations ranging from 1.7% to 9.0%. Compared with the conventional methods, the proposed method was proved to be a rapid, simple, safe and available for the determination of nitroimidazoles in water.