痕量铀的伏安极谱测量法研究

Study of trace uranium determination by adsorptive stripping voltammetry

运用伏安极谱法(AdSV)对水样中痕量U的测定进行了研究,发现在pH为2.3左右的Na_2SO_4介质中U与氯冉酸(CAA)形成电活性络合物,吸附在悬汞电极上,于-0.10V处(vs.Ag/AgCl)产生一灵敏的阴极溶出峰,其峰高与U浓度在10~100ppb范围内呈良好的线性关系,检出限为150ppt。对该体系吸附伏安行为和测量条件进行了研究,初步建立了测定痕量铀的方法,运用该法对样品进行了痕量U浓度的测量,结果令人满意。

A highly sensitive and selective method for determination of trace uranium by adsorptive stripping voltamnmtry（AdSV） is presented. The method is based on adsorptive accumulation of uranium（VI） -ehloranilic acid（CAA） complex onto a hanging mercury eleetrode（HMDE） ,followed by reduction of the adsorbed species by voltamnletrie scan. Influenee of effective parameters such as pH, deposition potential and deposition time on the sensitivity- were studied. The peak current was proportional to the concentration of U（VI） in the range of 10ppb tol00ppb. The detection limit was calculated to 150ppt. The possible interference by major metal i- ons are investigated. The application of this method was tested in the determination of U （VI）in synthetic and natural water sam- ples.