Abstract：In phosphoric acid, trace gold 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 . 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 (ΔA) between inhibitory system and non-inhibitory system was measured at 520 nm. The results showed that ΔA 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%.
宋学省. 金-溴酸钾-番红花红O阻抑动力学光度法测定痕量金[J]. 冶金分析, 2014, 34(12): 62-65.
SONG Xue-sheng. Determination of trace gold by inhibitory kinetic spectrophotometry with gold-potassium bromate-safranine O system. , 2014, 34(12): 62-65.
