铬天青S分光光度法测定铅

Spectrophotometric Determination of Lead

利用铬天青S（CAS）在有溴化十六烷基三甲胺（CTMAB）存在下的0．5mol／I。硝酸介质中可与Pb^2＋形成红褐色络合物的原理，建立一种新的测定铅的分光光度法。Pb^2＋-CAS络合物的最大吸收峰位于584nm，在该波长处，Pb^2＋质量浓度在O～O．8μg／mL范围内与吸光度呈良好线性关系，其回归方程为A=0．888 5ρ-0．0024，表观摩尔吸收系数ε584nm=1．46×10^5L／（mol·cm）。用该方法测定土豆和硝酸钠中的铅，结果满意。

Chrome azurol S（CAS） and Pb^2＋ forms a red-brown complex in 0. 5 mol/L nitric acid medium in the presence of cetyhrimethylammonium bromide, a new spectrophotometric method for determination of lead （l]） is established. The maximum absorption wavelength of the Pb^2＋-CAS complex is located at 584 nm. A good linearity is presented between the concentration range of 0-0.8μg/mL of Pb^2＋ and absorbance（A） at this wavelength, and its regression equation is A = 0. 888 5p- 0. 002 4. The apparent molar absorption coefficient is 1.46×10^5 L/（mol · cm） at 584 nm. This method is satisfactorily used for determination of lead in potato and sodium nitrate samples.