气相色谱/质谱法测定水中12种多氯联苯类化合物

Determination of 12 Polychlorinated biphenyls in water by gas chromatography/mass spectrometry

目的建立气相色谱/质谱法联用技术同时测定水中PCB81、PCB77、PCB123、PCB118、PCB114、PCB105、PCB126、PCB167、PCB156、PCB157、PCB169、PCB189,12种多氯联苯类化合物的分析方法。方法采用液-液萃取技术分别在中性和酸性环境下用二氯甲烷提取水样中的目标物,萃取液过无水硫酸钠干燥,氮吹,气相色谱/质谱法检测,以保留时间和选择离子定性,外标法定量,并与全自动固相萃取法比较水中目标物的回收率。结果 12种化合物在试验范围内分离效果好,曲线相关系数(R2)>0.996,检出限(LOD)为4.5~9.7ng/L。液-液萃取:中性条件下样品平均加标回收率在66.2%~90.2%,相对标准偏差(RSD)3.45%~8.63%;酸性条件下平均加标回收率在84.3%~98.3%,相对标准偏差(RSD)3.18%~6.72%;全自动固相萃取样品平均加标回收率在23.5%~36.2%,相对标准偏差(RSD)2.25%~4.96%。结论液-液萃取样品加标回收率明显好于全自动固相萃取,特别是在酸性条件下目标物回收效果最好。

Objective To establish a method of gas chromatography/mass spectrometry which can detect 12 kinds of Polychlorinated biphenyls in water：PCB81、PCB77、PCB123、PCB118、PCB114、PCB105、PCB126、PCB167、PCB156、PCB157、PCB169、PCB189.Methods The technique of liquid-liquid extraction was used in neutral and acidic environment to extract the target compounds in water by Methylene chloride, than extractive was dried by anhydrous sodium sulfate and nitrogen gas, at last be detected by gas chromatography/mass spectrometry. Retention time and selected ions were used for qualitative analysis, external standard for quantitative analysis. Results The separate rates of 12 kinds of compounds were well,and the correlation coefficients were more than 0.996,the minimum detection concentration were 0.045μg/L^0.097μg/L. The average recovery rates were 66.2% ~90.2% in neutral environment extracted by Liquid-liquid extraction technique and the relative standard deviation were 3.45%~8.63%;The average recovery rates were 84.3%~98.3% in acidic environment and the relative standard deviation were 3.18% ~6.72%;while with auto solid phase extraction the average recovery rates were 23.5% ~36.2%,and the relative standard deviation were 2.25% ~4.96%.Conclusions The sample＇s recovery rates extracted by liquid-liquid technique were better than which extracted by automatic solid phase extraction, especially in acidic environment.