柱前衍生-气相色谱法同时测定水中醛酮类和硝基苯类化合物

建立了柱前衍生-气相色谱法同时测定水样中醛酮类及硝基苯类化合物含量的检测方法。对影响衍生效率的因素如溶液的酸度、反应温度和时间、衍生试剂2,4-二硝基苯肼(DNPH)的用量等因素进行了试验,确定了DNPH与醛酮类化合物反应生成腙的最佳条件为pH=3时40℃恒温水浴反应1h。利用二氯甲烷萃取反应生成的腙和硝基苯类化合物,旋转蒸发仪浓缩,氮吹转换甲醇相,使用电子捕获检测器的气相色谱仪测定目标化合物。各化合物的质量浓度与其色谱峰峰面积的线性相关系数均在0.9989以上,方法检出限为0.01～0.03μg/L,相对标准偏差(RSD,n=6)均低于6.0%,回收率在89.5%～110.2%。方法简便、经济、回收率高,可用于水质中醛酮类及硝基苯类化合物的检测。

Simultaneous Determination of Nitrobenzene, Aldehyde and Ketone Compounds in Waters by Gas Chromatography with Pre-column Derivatization

A method for simultaneous determination of nitrobenzene,aldehyde and ketone compounds in water samples by gas chromatography with pre-column derivatization was developed.Parameters affecting the derivatization efficiency,such as pH,reaction time and temperature,dosage of derivatization reagent of 2,4dinitrophenylhydrazine (DNPH) were tested and optimized.The optimum derivatization condition was set at pH=3 and 40 ℃ for an hour in a water bath.The reaction products of hydrazone and nitrobenzene compounds were extracted with dichloromethane,concentrated by rotary evaporator and converting the system to methanol medium by nitrogen-blowing.And then the target compounds were determined by gas chromatograph with electron capture detector.The detection limits of the method for organic components were in the range of 0.01 ～ 0.03 μg/L and the correlation coefficients of the calibration curves for the analytes were between 0.998 9 ～ 0.999 8.The recoveries were 89.5% ～ 110.0% with precision of < 6.0% RSD (n=6).The method provides the advantages of high recovery,high efficiency,economy,simple operation and is suitable for routine analysis of nitrobenzene,aldehyde,and ketone compounds in water samples.