顶空-气相色谱法同时测定地表水和废水中吡啶及其衍生物的含量

Simultaneous Determination of Pyridine and Its Derivatives in Surface Water and Wastewater by Gas Chromatography with Headspace

提出了顶空-气相色谱法同时测定地表水和废水中吡啶及其衍生物(包括2-甲基吡啶、3-甲基吡啶、4-甲基吡啶)含量的方法。取40 mL水样,用0.5 mol·L^(-1)氢氧化钠溶液和10%(体积分数)磷酸溶液调节其酸度至约pH 10,记录酸、碱用量;采样时先在采样瓶中加入上述等量的酸或碱,然后采集样品置于样品瓶中,不留液上空间。取10.0 mL上述样品,移入已预先加入3.0 g氯化钠的顶空瓶中,立即加盖摇匀,于80℃平衡30 min,所得气体进入气相色谱仪,在HP-INNOWAX色谱柱上用升温程序分离,用氮磷检测器检测,外标法定量。结果表明,各化合物的质量浓度在一定范围内与对应的峰高呈线性关系,检出限(3.143s)为0.88~5.3μg·L^(-1);按照标准加入法进行回收试验,回收率为95.0%~105%,测定值的相对标准偏差(n=6)均小于5.0%;方法用于地表水和废水样品的分析,地表水中4种化合物均未检出,而废水中这4种化合物均有检出,检出量为0.009~7.48 mg·L^(-1),加标回收率为87.5%~112%。

A method for simultaneous determination of pyridine and its derivatives including 2-methylpyridine,3-methylpyridine,and 4-methylpyridine in surface water and wastewater,was proposed by gas chromatography with headspace.40 mL of water sample was taken and its acidity was adjusted to about pH 10 with 0.5 mol · L^(-1) sodium hydroxide solution and 10%(volume fraction) phosphoric acid solution.The amounts of acid and alkali were recorded.Acid or alkali was added in the sample bottle,and had an equal amount that recorded.The sample was placed in the sample bottle without leaving any space above the liquid.10.0 mL of the above sample was taken and placed into a headspace vial that had pre-filled with 3.0 g of sodium chloride.The mixture was covered immediately and equilibrated at 80 ℃ for 30 min.The obtained gas was introduced into the gas chromatograph,separated by heating program on the HP-INNOWAX column,and determined by the nitrogen phosphorus detector,with the external standard method for quantification.As shown by the results,linear relationships between the corresponding peak heights and mass concentrations of compounds were found in definite ranges,with detection limits(3.143s)in the range of 0.88-5.3 μg · L^(-1).Test for recovery was made by the standard addition method,giving results in the range of 95.0%-105%,with RSDs(n=6) of the determined values less than 5.0%.This method was used for the analysis of surface water and wastewater samples,and none of 4 compounds was detected in the surface water sample,while all 4 compounds were detected in the wastewater sample,with detection amounts in the range of 0.009-7.48 mg · L^(-1),and the spiked recoveries were in the range of 87.5%-112%.