动能歧视碰撞池-电感耦合等离子体质谱法测定光卤石中溴

采用热水浸取的方法溶解光卤石样品中溴元素,以动能歧视碰撞池(KED)为测量模式消除了多原子分子离子的干扰,以50.0ng/mL ¹⁸⁷Re为内标进行校正,建立了电感耦合等离子体质谱法(ICP-MS)测定光卤石中溴含量的方法。对热水浸取的时间和氦气流量进行了优化,确定浸取时间为10min,氦气流量为4.7mL/min。对基体效应进行了考察,结果表明,通过控制测定溶液的基体质量浓度不大于0.50mg/mL,可有效克服基体效应。在优化的实验条件下测定溴标准溶液系列,结果表明,溴质量浓度在0.100~400ng/mL范围内与其质谱强度呈线性关系,相关系数为0.9996。方法检出限为0.424μg/g,方法测定下限为1.41μg/g。采用实验方法分别对5个不同溴含量水平的光卤石样品中溴进行测定,结果的相对标准偏差(RSD,n=9)在1.7%~4.7%之间;并进行加标回收试验和方法对比试验,加标回收率在98%~108%之间,测定值和品红分光光度法基本一致。

Determination of bromine in carnallite by kinetic energy discrimination in collision cell-inductively coupled plasma mass spectrometry

Bromine in carnallite sample was dissolved by hot water leaching. The interference of multi-atomic molecular ions was eliminated using kinetic energy discrimination (KED) in collision cell as the measurement mode. 50.0ng/mL ¹⁸⁷Re was selected as the internal standard for correction. Consequently the determination method of bromine in carnallite by inductively coupled plasma mass spectrometry (ICP-MS) was established. The hot water leaching time and the flow rate of helium gas were optimized and the following conditions were used: the leaching time was 10min and the flow rate of helium was 4.7mL/min. The matrix effect was investigated and the results showed that it could be effectively overcome by controlling the mass concentration of the solution to be no more than 0.50mg/mL. The standard solution series of bromine were determined under the optimized experimental conditions. The results indicated that the mass concentration of bromine in range of 0.100-400ng/mL was linear to the mass spectrometry intensity with correlation coefficient of 0.9996. The detection limit was 0.424μg/g and the low limit of determination was 1.41μg/g. The proposed method was applied for the determination of bromine in five carnallite samples with different bromine contents. The relative standard deviations (RSD, n=9) were between 1.7% and 4.7%. The spiked recovery test and method comparison test were also conducted. The spiked recoveries were between 98% and 108%. The found results were basically consistent with those obtained by the magenta spectrophotometry.