分散液液微萃取-气相色谱法快速测定水中15种硝基苯类物质

摘要

A method for the determination of 15 kinds of nitroaromatics in aqueous samples was developed by dispersive liquid-liquid microextraction and gas chromatography with electron capture detection. A high-density extractant applied in electron capture detector was screened out. The chromatographic conditions, types and dosages of extractants, types and dosages of dispersants, extraction time and the extraction temperature were optimized. The results showed that DB-35 capillary column had the best separation performance for the 15 kinds of nitroaromatics. The nitroaromatics could be separated within 22 min using programmed temperature control as follows: holding at an initial temperature of 80℃ and then heating to 180℃ at a ramping rate of 5℃ / min. For the extraction of 15 kinds of nitroaromatics from 5 mL of aqueous sample, the extraction equilibrium could be reached within 30 s with a high extraction recovery of over 90%when using 100 μL of chlorobenzene as extracting solvent and 400 μL of methanol as disperser solvent. In addition, the enrichment factor could approach a high value of 45. 0 - 48. 8. The sediment collected by centrifugation was injected and analyzed by gas chromatography with electron capture detector. The limits of quantification of the developed method were 0. 03 - 0. 15 μg / L ( S / N = 10). The linear range was from 0. 20 μg / L to 50. 0 μg / L, while the correlation coefficients (R2 ) were more than 0. 998. At the spiked level of 0. 200 μg / L, the relative standard deviations of this method were 3. 3% -8. 9% , the relative recoveries ranged from 86. 0% to 103. 5% . At higher spiked level, the relative standard deviations were less than 5% , and the relative recoveries ranged from 94. 5% to 101. 5% .%建立了分散液液微萃取-气相色谱电子捕获检测器测定水中15种硝基苯类物质的方法.筛选出了具有高密度且能够适用于电子捕获检测器的萃取剂.优化了色谱条件,对萃取剂种类及用量、分散剂种类及用量、萃取时间、萃取温度等条件进行了优化.DB-35毛细管柱对15种硝基苯类物质具有最好的分离效果.使用程序升温,初始80℃ 保持2 min,以5℃/min速率升温至180℃,可以在22 min内完成分离.以100μL氯苯作为萃取剂、400μL甲醇作为分散剂,对5.00 mL水样在室温下进行萃取,仅需30 s即可达到萃取平衡,15种目标物的萃取率均可达到90%以上,富集倍数达到45.0~48.8.离心分离,取下层沉积相进行气相色谱测定,使用电子捕获检测器检测,方法的定量限为0.03~0.15μg/L,线性范围为0.20~50.0μg/L,相关系数不低于0.998.方法的相对标准偏差在3.3%~8.9%之间,加标回收率在86.0%~103.5%之间.