二氧化钛涂覆中空纤维膜微萃取-电热蒸发-电感耦合等离子体质谱分析环境样品中痕量重金属

TiO_2-coated Hollow Fiber Micro-Extraction Combined with Electrothermal Vaporization-Inductively Coupled Plasma Mass Spectrometry for Trace Elements Analysis in Environmental Water Samples

采用溶胶-凝胶法制备了Ti O2涂覆中空纤维膜,并对其进行了X射线衍射和扫描电镜表征。考察了其对多种金属离子的吸附行为,最佳的萃取条件为试样的p H=8.0,在搅拌速率700 r/min下萃取30 min,使用100μL 1 mol/L HNO3进行解吸。基于此,建立了Ti O2涂覆中空纤维膜微型化固相萃取-电热蒸发（ETV）-电感耦合等离子体质谱（ICP-MS）联用测定环境水样中痕量重金属的新方法。本方法对Cr（Ⅲ）,Cu（Ⅱ）,Cd（Ⅱ）和Pb（Ⅱ）的检出限分别为0.039,0.021,0.009和0.018 ng/m L,富集倍数为10.3~18.6倍。自制Ti O2涂覆中空纤维膜的制备重现性（RSD）为4.5%~6.8%（批内）和7.7%~9.6%（批间）。本方法被成功应用于标准水样、东湖水和雪水中Cr（Ⅲ）,Cu（Ⅱ）,Cd（Ⅱ）和Pb（Ⅱ）的分析。另外,将Ti O2涂覆中空纤维膜与Ti O2涂覆中空纤维膜搅拌棒进行了比较,结果表明,Ti O2涂覆中空纤维膜不仅制备简单,而且对目标金属离子具有较高的萃取效率和吸附容量。

TiO2 coated hollow fiber （HF） was prepared by sol-gel method and characterized by X-ray powder diffraction and scanning electron microscope. The adsorption performances of the self-prepared TiO2 coated HF for interest metal ions were explored. The sample solution was extracted for 30 rain at pH 8.0 under stirring at speed of 700 r/min, then desorpted with 100 μL of 1 mol/L HNO3. On the basis of this, a method combining TiO2 coated HF micro-solid phase extraction with electrothermal vaporization-inductively coupled plasma mass spectrometry （ICP-MS） was developed for the determination of trace metal ions in environmental water samples. Under the optimized conditions, the limits of detection obtained by the proposed method were 0. 039, 0.021,0.009 and 0.018 ng/mL for Cr（Ⅲ）, Cu（Ⅱ）, Cd（Ⅱ） and Pb（Ⅱ） with enrichment factors of 12.5, 11.7, 10.3 and 18.6, respectively. The preparation reproducibility of self-prepared TiO2 coated HF ranged from 4.5% to 6.8% （n = 9） in one batch, and from 7.7% to 9.6% （n = 7 ） in batch-to-batch. The developed method has been validated by analyzing a certified reference material （GSBZ50009-88 200925 ） and also applied to the analysis of Cr（Ⅲ）, Cu（Ⅱ）, Cd（Ⅱ） and Pb（Ⅱ） in East Lake water and snow water successfully. Meanwhile, TiO2 coated HF stir bar was prepared for a comparison and it was demonstrated that TiO2 coated HF displayed higher extraction efficiency and adsorption capacity for target ions.