分散液相微萃取-石墨炉原子吸收光度法测定水中铊

Detecting Thallium in Water Samples using Dispersive Liquid Phase Microextraction-Graphite Furnace Atomic Absorption Spectroscopy

目的基于离子缔合反应,建立溶剂去乳化分散液相微萃取联合石墨炉原子吸收光度法测定水中铊的方法。方法采用溴水为氧化剂,样品中的铊被氧化为铊（Ⅲ）,与Cl-反应生成配阴离子TlCl4-,加入三辛胺作为萃取剂,TlCl4-与三辛胺形成离子缔合物的同时被萃取,在乙醇分散剂的作用下,实现铊的分散液相微萃取,萃取完成后,加入去乳化剂进行相分离,取有机萃取相进行石墨炉原子吸收测定。采用胶体钯作为基体改进剂,两步干燥和两步灰化的升温程序,提高石墨炉原子吸收测定的精密度和灵敏度。结果本研究所建立的方法在铊0.05~2.0μg/L浓度范围内线性良好,方法检出限为0.011μg/L,精密度为9.9%,加标回收率在94.0%~103.0%之间。结论本研究建立的方法简单灵敏,适合水样中铊的批量分析。

Objective To develope a method of solvent demulsification dispersive liquid phase microextraction（SD-DLPME）based on ion association reaction coupled with graphite furnace atomic absorption spectroscopy（GFAAS）for detecting thallium in water samples.Methods Thallium ion in water samples was oxidized to Tl（Ⅲ）with bromine water,which reacted with Cl-to form TlCl4-.The ionic associated compound with trioctylamine was obtained and extracted.DLPME was completed with ethanol as dispersive solvent.The separation of aqueous and organic phase was achieved by injecting into demulsification solvent without centrifugation.The extractant was collected and injected into GFAAS for analysis.With palladium colloid as matrix modifier,a two step drying and ashing temperature programming process was applied for high precision and sensitivity.Results The linear range was 0.05-2.0μg/L,with a detection limit of 0.011μg/L.The relative standard derivation（RSD）for detecting Tl in spiked water sample was 9.9%.The spiked recoveries of water samples ranged from 94.0% to 103.0%.Conclusion The method is simple,sensitive and suitable for batch analysis of Tl in water samples.