双衍生GC-MS法测定污水臭氧化过程的醛和羧酸

Method of GC/MS with Double Derivation for Simultaneous Detection of Aldehydes and Carboxylic Acids during Ozonation of Wastewater

以O-2,3,4,5,6-pentafluorobenzylhydroxylamine(PFBHA)和bis(trimethylsilyl)trif-luoroacetamide(BSTFA)为衍生化试剂,建立了同步分析城市污水厂二级出水臭氧深度处理出水中的醛(甲醛、乙醛、丙醛、乙二醛)和羧酸(丙酮酸)的双衍生气相色谱-质谱(GC-MS)方法。在电子轰击(EI)源下用选择离子模式进行分析,结果表明:甲醛、乙醛、丙醛在5μg/L～2mg/L,乙二醛和丙酮酸在5μg/L～1mg/L浓度范围内线性较好;各种物质的检测回收率均在74%以上,平均相对标准偏差<14%。对实际水样的测定表明,污水厂二级出水中含有少量的醛类和丙酮酸,臭氧处理会导致这些物质明显增加。

A method of GC/MS with double derivation for simultaneous detection of aldehydes and earboxylic acids in the ozonated secondary effluent from a WWTP was established by using 0-2,3,4,5,6- pcntafluorobenzylhydroxylamine （PFBHA） and bis （trimethylsilyl） trifluoroaeetamide （BSTFA） as derivatives. An analysis was performed with electron bombardment source in selected ion monitoring mode. The results show that formaldehyde, acetaldehyde and propionaldehyde have a good linear relationship within the concentration range from 5 μg/L to 2 mg/L and glyoxal and pyruvic acid from 5 μg/L to 1 mg/L. The average recoveries of the 5 analytes are above 74% , and the relative standard deviations （RSD） are under 14%. It is found that ozonation of the secondary effluent could increase the levels of the above chemicals markedly while a small amount of them already exist before ozonation.