固相萃取—热裂解—气相色谱—串联质谱法测定盐湖卤水中溶解性有机质

以青藏高原地区的大柴旦盐湖湖表卤水为研究对象,采用不同的固相萃取(Solid phase extraction,SPE)材料(HLB,PPL,ENVI-18,ENVI-Carb,XAD8和XAD4)对大柴旦盐湖湖表卤水中DOM进行了分离和富集,初步建立了从高盐体系盐湖卤水中高效分离富集出具有代表性的溶解性有机质(Dissolved organic matter,DOM)的方法,系统的考察了pH,上样体积,柱流速和洗脱溶剂对DOM回收率的影响。结合傅里叶变换红外光谱分析(Fourier transform infrared spectroscopy,FTIR)、热裂解—气相色谱—串联质谱分析(Pyrolysis-gas chromatography-mass spectrometry,Py-GC/MS)进一步对盐湖卤水分离物进行了谱学表征。研究结果表明,盐湖卤水在酸性条件下(pH=2),柱流速为0.5 mL/min时有助于吸附剂对DOM的吸附,而随着上样体积的增加,DOM的回收率逐渐下降,而甲醇是比较理想的洗脱剂。大柴旦盐湖湖表卤水中的DOM主要以芳香类,碳水化合物以及部分脂肪族化合物为主,而含氮类化合物含量较少。

Characterization of Dissolved Organic Matter Isolated by Solid Phase Extraction from the Hypersaline Lake with Pyrolysis|Gas Chromatography|Mass Spectrometry

:Several solid|phase extraction (SPE) adsorbents(HLB,PPL,ENVI|18,ENVI|Carb,XAD8 and XAD4)were selected to isolate DOM from the surface water from hypersaline Da Qaidam Lake in the Tibetan Plateau,China. The effects of critical SPE variables such as pH,loading volume,flow rate,and eluent were systematically investigated based on dissolved organic matter (DOC) recovery. Fourier transform infrared spectroscopy (FTIR) and pyrolysis|gas chromatography|mass spectrometry (Py|GC/MS) were used to characterize the hypersaline lake DOM isolated by PPL adsorbent. The results indicated that the adsorbents exhibited higher DOM recovery under acid condition(pH=2),less sampling volumes and flow rate at 0.5 mL/min. In addition,methanol was an ideal eluent of DOM isolated from hypersaline lake by SPE. The DOM of Da Qaidam Saline Lake surface water predominately comprised by aromatic components,carbohydrates and aliphatic compounds,and the contents of N|containing compounds were minor.