金-溴酸钾-番红花红O阻抑动力学光度法测定痕量金  

Determination of trace gold by inhibitory kinetic spectrophotometry with gold-potassium bromate-safranine O system

作　　者：宋学省[1] 

机构地区：[1]山东临沂大学,山东临沂276005

出　　处：《冶金分析》2014年第12期62-65,共4页Metallurgical Analysis

基　　金：山东省青年奖励基金(2011BSA13013)

摘　　要：在磷酸介质中,痕量金（Ⅲ）对溴酸钾氧化番红花红O的变色反应有很强的抑制作用,据此,建立了阻抑动力学光度法测定痕量金（Ⅲ）的新方法.实验表明,在两支25 mL比色管中分别加入0.6 mL 1.0 g/L番红花红O溶液、0.5 mL 6.0 mo1/L磷酸,其中一支加适量金（阻抑体系）,另一支不加（非阻抑体系）,再分别加0.7 mL 0.05 mo1/L溴酸钾溶液,定容至10 mL,在100℃水浴中反应20 min,于波长520 nm处测定阻抑和非阻抑体系的吸光度差,金的浓度在0.5～6 ng/mL范围内与△A呈良好的线性关系.方法检出限为7.62×10-12 g/mL,表观活化能为74.97 kJ/mol.方法用于矿石中金的测定,测得结果与原子吸收光谱法一致,相对标准偏差（RSD,n=6）为3.1％～3.5％,回收率为99％～105％.In phosphoric acid,trace gold （Ⅲ） exerted strong inhibitory effect on the color changing reaction of safranine O oxidized by potassium bromate.Based on these phenomena,a new inhibitory kinetic spectrophotometric method was established for the determination of trace gold （Ⅲ）.The experiment indicated that two 25 mL colorimetric tubes were added into 0.6 mL of 1.0 g/L safranine O solution and 0.5 mL of 6.0 mol/L phosphoric acid,respectively.Trace gold was added into one tube （inhibitory system）,but not added into another （non-inhibitory system）.Then,0.7 mL of 0.05 mol/L potassium bromate was added into both tubes.After dilution to 10 mL,the tubes were heated in water bath at 100 ℃ for 20 min.The absorbance difference （△A） between inhibitory system and non-inhibitory system was measured at 520 nm.The results showed that △A exhibited good linearity to the concentration of gold in range of 0.5-6 ng/mL.The detection limit of method was 7.62× 10-12 g/mL and the apparent activation energy was 74.97 kJ/mol.The proposed method was applied to the determination of gold in ore.The results were consistent with those obtained by atomic absorption spectrometry.The relative standard deviation （RSD,n=6） was 3.1%-3.5%,and the recoveries were between 99% and 105 %.

关 键 词：金 溴酸钾 阻抑动力学光度法 番红花红O 

分 类 号：O657.3[理学—分析化学] P575.4[理学—化学]