碱熔-阳离子交换树脂分离-离子色谱法/电感耦合等离子体质谱法测定地球化学调查样品中卤素

Determination of Halogens in Geochemical Survey Samples by Ion Chromatography/ICP-MS with Alkali Melting-Cation Exchange Resin

地质样品中的卤素具有中度不相容性、较强的挥发性和流体迁移能力,作为示踪元素对反演流体和挥发分相关的地球化学过程具有重要意义。由于地球化学调查样品中的卤素含量低以及具有较强挥发性,测定难度较大。F、Cl、Br、I主要采用单独或分组熔矿的方法进行制备和测定,操作难度大、消耗时间长、分析效率低。采用Na_(2)O_(2)和NaOH混合试剂碱熔后分取溶液,加入阳离子交换树脂,静态交换2~3 h,除去溶液中大量的阳离子,减少基体干扰,利用离子色谱测定F、Cl,利用电感耦合等离子体质谱法测定Br、I。结果表明:方法测定F、Cl、Br、I的检出限分别为6.9、10.2、0.87、0.27μg/g,相对标准偏差(RSD,n=12)在2.8%~8.5%,均小于10%。方法具有结果准确、简单、快速、经济的特点,在地球化学调查样品分析中具有良好的应用前景。

Halogens in geological samples have moderate incompatibility,strong volatility and fluid migration ability.As tracer elements,they are of great significance for inversion of geochemical processes related to fluids and volatiles.Due to the low halogen content and strong volatility in the geochemical survey samples,the determination is difficult.F,Cl,Br and I are mainly prepared and measured by the method of smelting ore alone or in groups,which is difficult to operate,take a long time,and have low analysis efficiency.In this paper,the mixed reagent of Na_(2)O_(2) and NaOH is used to separate the solution after alkali melting,then cation exchange resin was added for static exchange for 2 to 3 hours to remove a large amount of cations in the solution and reduce matrix interference,we use ion chromatography to determine F and Cl,and use inductively coupled plasma mass spectrometry method for the determination of Br and I.The results showed that the detection limits of F,Cl,Br and I by this method were 6.9,10.2,0.87 and 0.27μg/g,respectively,and the relative standard deviations(RSD,n=12)were between 2.8%and 8.5%,all less than 10%.The method has the characteristics of accurate,simple,rapid and economical results,and has a good application prospect in the analysis of geochemical survey samples.