硫酸肼比浊法测定微量硒

Hydrazine sulfate turbidimetry determination of trace selenium

依据硒（Ⅳ）在以甘油为稳定剂,盐酸为反应介质的条件下,被过量硫酸肼还原,使体系形成稳定悬浊液的原理,建立了比浊法测定硒的方法。探讨了盐酸用量、甘油用量、反应温度和反应时间以及硫酸肼用量等5个关键因素的影响,确定了最佳测定条件。实验结果表明：大量的共存物质不干扰测定。在选定的实验条件下,线性方程为：ΔA750nm=12.725ρ＋0.0076,在2.0×10^-4-3.2×10^-2mg·m L^-1范围内线性关系良好,相关系数（R2）=0.9911,方法的检出限为1.2×10^-4mg·m L^-1。方法用于测定强化营养盐中总硒,回收率在97.0-103.5%之间,RSD为1.8%。

A new nephelomtric method was developed for the determination of selenium. The proposed method is based on the reaction of Se（ Ⅳ） with excess hydrazine sulfata in HCl medium to liberate elemental selenium,which subsequently from stable suspension in the presence of glycerin used as stabilizer. The influences of five key factors such as dosage of hydrochloric acid and glycerol,reaction temperature and time,and dosage of reducing agent were investigated,and the optimum conditions were determined. A large number of substances do not interfere with the determination of coexistence. Under the chose conditions,the linear regression equation was ΔA750nm= 12. 725ρ ＋ 0. 0076. A good linear relationship was obtained in 2. 0 × 10^-4- 3. 2 × 10^-2mg·m L^-1linear range. The realative coefficient was 0. 9911. The detection limit was 1. 2×10^-4mg·m L^-1. The method used to measure total selenium of strengthen nutrition salt,RSD is 1. 8%,the average recovery is 97. 0 - 103. 5%.