吹扫捕集-气相色谱-质谱联用测定天然水体中异戊二烯的研究

Purge-trap Gas Chromatography and Mass Spectrometric Method for Analysis of Isoprene in Natural Waters

建立了吹扫捕集-气质联用分析天然水体中痕量异戊二烯的方法,确定了最佳实验条件：吹扫流量50 m L/min、吹扫时间15 min、毛细管分离柱类型（Rt-Alumina BOND/KCl）以及程序升温等。本方法对于测定水体中异戊二烯浓度的相对标准偏差RSD〈4%（n=6）,回收率为92%-102%,检出限为0.5 pmol/L。实验表明,水样中异戊二烯浓度在60 d以内没有发生明显变化。利用本方法测得青岛胶州湾及附近河流入海口水样中异戊二烯的浓度在60.8-278.7 pmol/L之间,黄河口水样浓度范围为44.7-77.2 pmol/L,与文献报道的其它近岸及河口水体中的浓度相当,表明本方法能够应用于天然水体中异戊二烯浓度的准确分析。

Gas chromatography with mass spectrum detector（ GC-MSD） coupled with purge-and-trap system was set up to analyze the concentration of isoprene in natural waters. The best experimental conditions were established,including purge gas flow rate（ 50 m L / min）,purge time（ 15 min）,the optimum capillary column（ Rt-Alumina BOND / KCl） and the appropriate condition of temperature programming. When analyzing isoprene in natural waters,the precision was 4%（ n = 6）,the detection limit was 0. 5 pmol / L and the recovery was 91%-102%. The preservative experiment showed that there was no obvious variation in sample concentrations of isoprene within 60 days. The concentrations of isoprene measured with the method ranged from 60. 8 to 278. 7 pmol / L in the Jiaozhou Bay and its adjacent river estuaries and from 44. 7 to77. 2 pmol / L in Yellow River estuary,which was in good accord with those results reported in literatures in other coastal waters. In conclusion,the analytical method could meet the requirements of the analysis of concentration of isoprene in natural waters.