采用热表面电离质谱计,对以Li_3PO_4作为加载物的~6Li~+、~7Li~+锂离子流之比进行了测定。在详细研究分析时的试样酸度、离化带温度、蒸发带温度与试样量,以及测量值随时间的变化等一系列测试条件后,建立了一种高精密度锂同位素分析方法。该法测量锂同位素丰度之比的相对标准偏差优于0.1％,最好时可达0.047％。并具有制样简单、分析时间短、质量分馏效应不明显等优点。 The ratio of ~ 6Li ~ +, ~ 7Li ~ + lithium ion current with Li_3PO_4 as loading was measured by hot surface ionization mass spectrometer. A series of high-accuracy lithium isotope analysis methods have been established after a series of test conditions such as sample acidity, temperature of ionization zone, temperature and sample volume of evaporation zone and the change of measured value over time. The relative standard deviation of the method for measuring the abundance ratio of lithium isotopes is better than 0.1%, the best when it reaches 0.047%. And has a simple sample preparation, analysis of time is short, the mass fractionation effect is not obvious advantages.