基于Cs2BO+2的正热电离质谱法测定样品中硼同位素时, 硼含量的准确测定直接制约着硼同位素测定的成败。 目前, 使用电感耦合等离子体原子发射光谱仪(ICP-OES)测定高盐样品的硼含量仍然存在很大问题, 主要体现在两个方面: 高盐的基体干扰和仪器检出限制约, 而仅仅依靠简单的稀释无法很好的解决这些困难。 因此对样品进行硼元素的预富集以及基体离子的去除是十分必要的。 在使用硼特效树脂进行硼元素的吸附时发现部分钠离子也会被同时吸附, 故采用3 mol·L-1的氨水可以洗脱大部分吸附的钠离子而不造成硼的损失, 达到了去除基体的目的。 随后使用10 mL 75 ℃的0.1 mol·L-1盐酸将硼特效树脂吸附的硼洗脱实现了样品中硼的富集。 ICP-OES测定硼含量时, 选择波长为208.900 nm, 样品的加标回收率在106.00%～108.40%之间, 检出限为0.006 mg·L-1, 定量下限为0.02 mg·L-1。 通过不同盐度下的12次重复实验, 其相对标准偏差小于5%, 在1.94%～3.37%之间, 因此该方法是可行的, 并不存在偶然误差。 联合此方法和Cs2BO+2离子的正热电离质谱法, 成功测定了8个地质石盐样品的硼含量及硼同位素组成。

The accurate content of boron directly restricts the boron isotope determination by using Positive Thermal Ionization Mass spectrometry based on Cs2BO+2 ion. At present, there is a big problem in determination of high salt and low boron samples with Inductively Coupled Plasma Optical Emission Spectrometer (ICP-OES), mainly in two aspects: high salt matrix interference and instrument detection limit, and simple dilution can not solve these difficulties very well. At present, the above two problems will be encountered when determining the boron content in the salt samples by ICP-OES, therefore, it is necessary to enrich boron and remove the matrix ions. In this paper, Amberlite IRA 743 boron-specific resin is applied to purify the boron element, and the high-salt matrix can be removed, but there are some sodium ions adsorbing at the same time. Using 3 mol·L-1 NH3·H2O can remove most of the adsorbed sodium ions and have no effect on the adsorbed boron. Then eluting boron from the resin with10 mL 0.1 mol·L-1 HCl at 75 ℃. 208.900 nm was chosen as the detection wavelength for boron, and the recoveries were in the range of 106.00%～108.40%; the detection identification and quantification limits are 0.006 and 0.02 mol·L-1, respectively. Through the 12 times repeated experiments under different salinities, the relative standard deviations range from 1.94% to 3.37%, which less than 5%, so we think the method is feasible, and there is no accidental error. Combining with this method and Positive Thermal Ionization Mass spectrometry based on Cs2BO+2ion, the deternination of the boron content and isotopic composition of eight salt samples are achieved.