论文部分内容阅读
建立了氢化物发生-原子荧光光谱法测定地质试样中Sn的方法。锡矿物试样用Na_2O_2-Na OH(5:1,m/m)于550℃~700℃熔融,以水及无水乙醇浸取,SnO_2-3与Fe,Mn,Ti等氢氧化物沉淀分离,为抑制Sn水解及硅酸析出,在20 g/L酒石酸-0.18 mol/L H_2SO_4介质中,以硫脲-抗坏血酸掩蔽残留干扰元素,于气液分离器中Sn(Ⅳ)被KBH_4-H_2SO_4还原为SnH_4,借助氩气导入屏蔽石英管氩-氢焰中原子化,测量Sn的荧光强度。对仪器参数、试样分解、试液制备、酸介质与浓度、试剂用量,共存元素影响等分析条件进行了实验优化。Sn量在2~100μg/L范围内与荧光强度呈线性关系,相关系数为0.99943,方法检出限(3σ/K)为0.0046μg/g。方法用于试样中0.0020%~0.131%Sn的测定,RSD(n=9~11)为2.5%~7.5%,回收率为98.0%~111.0%,测定值与其他方法结果或标准值相一致。
A method for the determination of Sn in geological samples by hydride generation-atomic fluorescence spectrometry was established. The tin mineral samples were molten with Na 2 O 2 -NaOH (5: 1, m / m) at 550-700 ° C, leached with water and ethanol, and precipitated with SnO_2-3 and Fe, Mn, Ti and other hydroxides In order to suppress the hydrolysis of Sn and the precipitation of silicic acid, residual interfering elements were masked with thiourea-ascorbic acid in 20 g / L tartaric acid-0.18 mol / L H 2 SO 4 medium, and Sn (Ⅳ) was reduced by KBH 4 -H 2 SO 4 in a gas- SnH_4, argon gas is introduced into the quartz tube by argon gas to atomize hydrogen flame, and the fluorescence intensity of Sn is measured. The parameters of the instrument, the sample decomposition, the preparation of the test solution, the acid medium and the concentration, the amount of the reagent and the effect of the co-existing elements were optimized experimentally. The linear relationship between the amount of Sn and the fluorescence intensity in the range of 2 ~ 100μg / L was 0.99943 and the detection limit (3σ / K) was 0.0046μg / g. The method was applied to the determination of 0.0020% ~ 0.131% Sn in samples with RSD (n = 9 ~ 11) of 2.5% -7.5% and recovery of 98.0% ~ 111.0%. The measured values are in agreement with the results of other methods or the standard values .