阳离子树脂交换分离-电感耦合等离子体质谱(ICP-MS)法测定地质石膏样品中硼

Determination of Boron in Geological Gypsum Samples by Inductively Coupled Plasma Mass Spectrometry with Cationic Resin Exchange Separation

为减少由于碱熔盐分对测定元素的干扰,通过考察熔矿体系、阳离子交换树脂加入量、树脂吸附时间、清洗液、同位素等条件的选择,建立了氢氧化钠碱熔-732型阳离子交换树脂交换分离,在线加入铑内标,电感耦合等离子体质谱(ICP-MS)法测定石膏中硼的方法。实验表明,0.5 g样品用氢氧化钠低温升至450℃熔融30 min后继续升温至700℃熔融10 min,分取浸取后溶液的10%(10 mL)上清液,采用5 g 732型阳离子交换树脂静态吸附1 h,在测定过程中选择氨水(2%)清洗进样管,同时选用11 B作为ICP-MS测定的分析同位素。同时由于石膏国家标准物质不包含硼元素的含量,采用高纯硫酸钙分别与岩石标准物质、水系沉积物国家标准物质和土壤国家标准物质混合配制成人工标准物质,结果显示,方法的检出限为0.76μg/g,相对标准偏差(RSD,n=7)为0.90%~1.7%,相对误差为1.56%~3.96%,加标回收率在97.5%~102%,方法快速、准确,记忆效应小,适合石膏中硼元素的测定。

In order to reduce the interference of alkali melt salt on the determination of elements,the ore melting system,the amount of cation exchange resin,resin adsorption time,cleaning fluid,isotope and other conditions were investigated,the exchange separation of sodium hydroxide alkali melt-732 cation exchange resin was established,rhodium internal standard was added online,and boron in gypsum was determined by inductively coupled Plasma Mass spectrometry(ICP-MS).The experiment showed that 0.5 g sample was fused with sodium hydroxide at 450℃for 30 min and then continued to be heated to 700℃for 10 min.10%(10 mL)of the extracted solution was divided into supernatant,which was absorbed by 5 g type 732 cation exchange resin static for 1 h.In the process of determination,ammonia(2%)was selected to clean the sample tube,and 11 B was selected as the analytical isotope for ICP-MS determination.Since the national reference material of gypsum did not contain boron,the artificial reference material was prepared by mixing the high purity calcium sulfate with the national reference material of rock,drainage sediment and soil,respectively.The results showed that the detection limit of the method was 0.76μg/g,and the relative standard deviation(RSD,n=7)was 0.90%—1.7%.The relative error was 1.56%—3.96%,and the recoveries were 97.5%—102%.The method is fast,accurate and has little memory effect.It is suitable for the determination of boron in gypsum.