Lu H, Mou S, Yan Y, Tong S, Riviello J M
College of Chemistry and Molecular Engineering, Peking University, Beijing, China.
J Chromatogr A. 1998 Mar 27;800(2):247-55. doi: 10.1016/s0021-9673(97)01127-8.
A novel, highly sensitive method for the simultaneous separation and determination of lead, copper, cadmium and other transition metals in drinking water was achieved by on-line sample pretreatment of chelation ion chromatography. Manganese, which coeluted with cadmium, was oxidized to permanganate by ammonium persulfate before injection. Permanganate, with bulk quantity of alkali, alkaline earth metals, iron and aluminum, was eliminated by pyrophosphoric acid-ammonium acetate buffer solution (pH 5.5), while retaining heavy and transition metals on a selective chelating resin (MetPac CC-1 column). Then, they were disabsorbed and transferred to a sulfonated cation exchanger (TMC-1 column). Finally, the concentrated trace metals were separated on a bifunctional ion-exchange column (CS5A) by a concentration gradient of oxalic acid and sodium nitrate eluents, coupled with post-column spectrophotometric detection with 2-[(5-bromo-2-pyridyl)azo]-5-diethylaminophenol (5-Br-PADAP) at 560 nm. The separation and color-development conditions were optimized. The detection limits for the method (signal-to-noise ratio = 3:1) were at or below the microgram l-1 level. The results of drinking water analyses were satisfactory.
通过螯合离子色谱在线样品预处理，实现了一种新颖、高灵敏度的同时分离和测定饮用水中铅、铜、镉及其他过渡金属的方法。与镉共洗脱的锰在进样前被过硫酸铵氧化为高锰酸盐。高锰酸盐与大量碱金属、碱土金属、铁和铝一起，被焦磷酸 - 醋酸铵缓冲溶液（pH 5.5）去除，而重金属和过渡金属则保留在选择性螯合树脂（MetPac CC - 1柱）上。然后，它们被解吸并转移到磺化阳离子交换剂（TMC - 1柱）上。最后，在双功能离子交换柱（CS5A）上，通过草酸和硝酸钠洗脱液的浓度梯度分离浓缩的痕量金属，并在柱后于560 nm处用2 - [(5 - 溴 - 2 - 吡啶基)偶氮] - 5 - 二乙氨基苯酚（5 - Br - PADAP）进行分光光度检测。优化了分离和显色条件。该方法的检测限（信噪比 = 3:1）处于或低于微克/升水平。饮用水分析结果令人满意。
