多元校正-多波长分光光度法同时测定水样中锌,镉和钴

提出在pH=8.98的硼砂-硼酸-氯化钠缓冲溶液中,利用锌、镉和钴与显色剂4-(2-吡啶偶氮)间苯二酚(PAR)发生显色反应时的光谱差别来对它们进行定量测定,测量波长范围为300～600 nm.研究发现,各显色络合物在其特征峰处的吸光度与待测物浓度成线性,而且在PAR的特征峰处,吸光度也与待测物浓度成线性.本工作利用不同的测量波长范围(300～450,450～600和300～600 nm)对这3种金属离子的合成样进行吸光度测量并采集数据,进而采用经典最小二乘法(CLS),主成分回归(PCR)和偏最小二乘(PLS)处理和分析,分析结果表明,波长范围为300～600 nm时,用PLS对数据进行处理的结果最好.该方法被用于实际水样的测定,结果令人满意.

Application of Multivariate Calibration Methods to the Simul Speetrophotometrics Determination of Zn2+,Cd2+ and Co2+ in Water Samples

This paper developed a simple and sensitive method,based on multivariate calibration,for the simultaneous multiwavelength spectrophotometric determination of Zn2+,Cd2+ and Co2+ in surface water samples.The method relies on the spectral differences between their complexes with 4-(2-pyridylazo)-resorcinol(PAR).The absorbance data were measured and recorded in wavelength range of 300~600 nm.It was found that both the absorbance of positive peak and negative valley are proportional to the concentration of each analyte.In addition,the results with the absorbance alterations at the two wavelengths analyzed showed that the linear ranges of each analyte at the two wavelengths were the same.Synthetic mixtures of the three metal ions were analyzed,and the data obtained with the three different wavelength ranges(i.e.,300~450 nm,450~600 nm and 300~600 nm) were processed by classical least squares(CLS),principal component regression(PCR) and partial least squares(PLS).The prediction results showed that PLS method with the spectral data in the range of 300~600 nm gives better results than the two other methods(CLS and PCR) in the the two other different wavelength ranges (450~600 nm and 300~600 nm).Following the validation of the proposed method,it was successfully applied for the determination of the three metal ions in two surface water samples.