固态萃取搅拌棒技术/气相色谱联用分析废水中的痕量爆炸物

制备了以聚醚砜酮(PPESK)为萃取相的新型固态萃取搅拌棒, 建立了一种固态萃取搅拌棒/热解吸器直接热解吸/气相色谱联用分析水样品中痕量爆炸物的新方法. 将萃取搅拌棒放入水样品中完成萃取后, 再直接放入热解吸器中于250 ℃热解吸, 将萃取到搅拌棒上的分析物一次性全部导入气相色谱柱中. 对于硝基苯类爆炸物, PPESK固态萃取搅拌棒的萃取容量比萃取纤维针提高1个数量级以上; 其萃取效率比PDMS固态萃取搅拌棒高2个数量级. 对所测定的7种爆炸物的最低检出限为0.008~0.022 μg/L, 方法的重复性误差(RSD)为6.9%~16%, 在线性浓度范围0.06~10.0 μg/L(除TNT)内, 线性相关系数r为0.9962~0.9998. 在优化的条件下对硝基苯类炸药生产过程中产生的废水进行了分析, 结果表明, 方法的回收率分别为88%~100%(低浓度样品)和61%~88%(高浓度样品), 该方法的重复性误差(RSD)小于11%.

Determination of Trace Level Nitroaromatic Explosives in Wastewater by Stir Bar Sorptive Extraction Coupled to Gas Chromatography

A novel poly(phthalazine ether sulfone ketone, PPESK) stir bar was prepared. The method for analyzing trace level nitroaromatic explosives in aqueous samples by stir bar sorptive extraction coupled to GC through thermal desorption was developed. The stir bar can be placed into thermal desorption unit after extraction at 250 ℃, so the sensitivity of the method can be enhanced because the analytes are completely transferred into GC column. The PPESK stir bar was proved to show one order of magnitude higher extraction capacity than the corresponding PPESK fiber and two orders of magnitude higher extraction efficiency than PDMS stir bar. The limits of detection(LODs) were in the range of 0.008—0.022 μg/L. The repeatability of the method(RSD) was from 6.9% to 15.9%, and the linear ranges were 0.06—10.0 μg/L with correlation coefficients of 0.9962—0.9998 except for TNT. By using the optimized extraction method, the wastewater samples produced in explosive production process were analyzed. The recoveries were from 88% to 100% for low concentration sample and from 61% to 88% for diluted high concentration sample. The RSDs of the repeatability of real sample application were lower than 11%.