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1 引言 作者发现在酸性条件下,钒对溴酸钾氧化铬蓝黑B(简写为EBB)的反应具有较高的催化活性,而EEB在乙二胺介质中,具有灵敏的极谱波。通过极谱仪器监测催化反应过程中铬蓝黑B浓度的变化,建立了测定痕量钒的催化动力学极谱法,方法具有简便、准确、灵敏等优点。 2 实验方法 取两支10ml比色管,加入0.1％EBB溶液0.5ml,2×10~(-3)mol/L KBrO_3溶液0.5ml,0.5mol/L H_2SO_40.5ml,然后,向其中一支比色管中加入一定量的钒,另一支不加钒,用水稀释至6ml,置70℃恒温器中,恒温反应7min,迅速取出,流水冷至室温,并加入0.01mol/L EDTA 1ml,10％乙二胺2ml,用水稀释至10ml,立即倒入电解池杯中,以原电电位为-0.40V进行阴极化扫描,记录Ep=-0.60V处的峰电流,求lg(i_0′/i′)
1 Introduction The authors found that under acidic conditions, vanadium has a high catalytic activity for the reaction of potassium bromate, chromium oxide, black and blue B (abbreviated as EBB), and EEB has a sensitive polarographic wave in ethylenediamine media. The polarographic apparatus was used to monitor the concentration of chromium, black and blue B during the catalytic reaction. The kinetic polarography was established for the determination of trace vanadium. The method is simple, accurate and sensitive. 2 Experimental methods Take two 10ml colorimetric tube, add 0.5ml of 0.1% EBB solution, 0.5ml of 2 × 10 ~ (-3) mol / L KBrO_3 solution, 0.5mol / L H_2SO_40.5ml, and then to one of the ratio Color tube add a certain amount of vanadium, the other without vanadium, diluted with water to 6ml, set 70 ℃ thermostat, constant temperature reaction 7min, quickly removed, cooled to room temperature, and add 0.01mol / L EDTA 1ml, 10 % Ethylenediamine 2ml, diluted with water to 10ml, immediately poured into the cell cup, the original electric potential of -0.40V cathodic scan, record Ep = -0.60V at the peak current, seeking lg (i_0 ’/ i ’)