Various refractory samples of boron such as titanium borides, rare earth borides, boron carbides having natural and non-natural isotopic composition were analysed by thermal ionization mass spectrometry as Na₂BO₂⁺ ions. Samples were fused with Na₂CO₃ directly on the filament after adjusting the B/Na mole ratio to 2 and in certain cases modifications in the loading technique were required to obtain precise ¹⁰B/¹¹B isotopic ratio. A few of the samples expected to have natural ¹⁰B/¹¹B ratio were observed to be slightly enriched in ¹⁰B. Dissolved samples as well as boron purified by extraction with 5% 2-Ethyl Hexane Diol(EHD) were analysed for ¹⁰B/¹¹B ratio to ascertain the accuracy of the results obtained by the direct fusion method. Precision of about 0.02% (1RSD) was obtained for ¹⁰B/¹¹B isotopic ratio measured in all the three types of samples. A good agreement of the dissolved sample and purified boron fraction with the directly fused sample validated the direct fusion method as a fast and reliable technique for isotopic analysis of boron in refractory samples.

硼的各种难熔样品，例如硼化钛、稀土硼化物、具有天然和非天然同位素组成的碳化硼，通过热电离质谱法分析为 Na ₂ BO ₂ ⁺离子。在将 B/Na 摩尔比调整为 2 后，样品与 Na ₂ CO ₃直接融合到灯丝上，在某些情况下，需要修改加载技术以获得精确的¹⁰ B/ ¹¹ B 同位素比。一些预期具有天然¹⁰ B/ ¹¹ B 比率的样品被观察到在¹⁰B. 对溶解的样品以及通过用 5% 2-乙基己烷二醇 (EHD) 提取纯化的硼进行分析，以确定¹⁰ B/ ¹¹ B 的比率，以确定通过直接融合方法获得的结果的准确性。在所有三种类型的样品中测得的¹⁰ B/ ¹¹ B 同位素比值的精度约为 0.02% (1RSD) 。溶解的样品和纯化的硼组分与直接熔融样品的良好一致性证实了直接熔融方法是一种用于难熔样品中硼同位素分析的快速可靠的技术。