流动注射化学发光法快速测定中药黄芪中的痕量铬

利用Cr3+对鲁米诺-H2O2化学发光反应的催化作用,流动注射化学发光法的优点,建立测定Cr3+的新方法,并通过H2SO3的还原作用,使Cr6+还原为Cr3+,从而实现对总铬的测定。确定此方法的最佳条件:负高压500V;鲁米诺浓度为2.50×10-4mol/L;过氧化氢的浓度为4.00×10-2mo1/L,鲁米诺溶液的pH为12,铬(Ⅲ)试液的pH为5。线性范围为1.0×10-6mg/mL～1.0×10-4mg/mL,检出限(S/N=3)为6.60×10-7mg/mL,对浓度为6.00×10-6mg/mLCr3+的标准溶液进行11次平行测定,其相对标准偏差为0.6%。该法成功地实现对中药黄芪样品中痕量铬的测定。

The rapid determination of trace chromium in medicine astragalus by flow injection chemiluminescence method

A new and effective method chemiluminescence-flow injection is established. It is based on the measurement of the light emitted from the Cr3+-catalysed oxidation luminol by H202. Cr6+ is reduced to Cr3+by H2SO3,thus the total chromium ion can be determined. Optimum conditions are obtained: applied voltage is -500V; luminol concentration is 2.50×10-4mol/L; hydrogen peroxide concentration is 4.00×10-2mo1/L; pH of luminol is 12,pH of Cr(Ⅲ) solution is 5. The linear range is 1.00×10-6mg/mL~1.0×10-4mg/mL and detection limit is 6.60×10-7 mg/mL (S/N=3),The relative standard deviation(RSD) is 0.6% for 11 measurements of 6.00×10-6 mg/mL Cr3+ standard solution. The method has been successfully applied to the determination of chromium of the medicine samples Astragalus.