Manzoori J L, Sorouraddin M H, Amjadi M
Department of Analytical Chemistry, Faculty of Chemistry, University of Tabriz, Tabriz, Iran.
Talanta. 2000 Oct 2;53(1):61-8. doi: 10.1016/s0039-9140(00)00383-0.
A highly sensitive spectrophotometric method is described for the determination of trace amounts of osmium(VIII), based on its catalytic effect on the oxidation of carminic acid by hydrogen peroxide. The reaction was monitored spectrophotometrically by measuring the decrease in absorbance of carminic acid at 540 nm after 3 min of mixing the reagents. The optimum reaction conditions were 1x10(-4) mol l(-1) carminic acid, 0.013 mol l(-1) hydrogen peroxide and pH 10 at 25 degrees C. By using the recommended procedure, the calibration graph was linear from 0.1 to 1.5 ng ml(-1) of osmium; the detection limit was 0.02 ng ml(-1); the RSD for five replicate determinations of 0.2-1.4 ng ml(-1) was in the range of 1.8-4.7%. The influence of several foreign ions on osmium determination were studied and the effect of interfering ions were removed by extracting osmium into isobuthyl methyl ketone and back extracting into sodium hydroxide solution.
描述了一种高灵敏度分光光度法，用于测定痕量锇（VIII），该方法基于锇（VIII）对过氧化氢氧化胭脂红酸的催化作用。通过在混合试剂3分钟后，测量540nm处胭脂红酸吸光度的下降，以分光光度法监测该反应。最佳反应条件为：在25℃下，胭脂红酸浓度为1×10⁻⁴mol/L，过氧化氢浓度为0.013mol/L，pH值为10。采用推荐的方法，校准曲线在0.1至1.5ng/ml的锇浓度范围内呈线性；检测限为0.02ng/ml；对0.2 - 1.4ng/ml进行五次重复测定的相对标准偏差在1.8 - 4.7%范围内。研究了几种外来离子对锇测定的影响，并通过将锇萃取到异丁基甲基酮中，再反萃取到氢氧化钠溶液中来消除干扰离子的影响。
