反相离子对色谱法测定硫代硫酸根和碘离子的研究

Study on Reversed Phase Ion Pair Chromatographic Determination of Thiosulfate and Iodide Anions

首次利用Ｓ２Ｏ２－３和Ｉ－与Ｈｇ－ＥＤＴＡ二元络合物通过柱前衍生形成ＥＤＴＡ－Ｈｇ－Ｓ２Ｏ３和ＥＤＴＡ－Ｈｇ－Ｉ两种三元络合物的方法，实现了对Ｓ２Ｏ２－３和Ｉ－的间接反相离子对色谱分离和紫外检测。在ＺｏｒｂａｘＯＤＳ柱上，用甲醇∶水＝２３∶７７作流动相，内含对离子ＴＢＡ＋３．０ｍｍｏｌ／Ｌ，ＥＤＴＡ１．０ｍｍｏｌ／Ｌ，ＮａＮＯ３２．０ｍｍｏｌ／Ｌ和缓冲剂ＫＨ２ＰＯ４－Ｎａ２ＨＰＯ４（ｐＨ７．０），紫外２５４ｎｍ检测。Ｓ２Ｏ２－３和Ｉ－的最小检出限分别为６１．１ｎｇ和３７．６ｎｇ。方法简便，选择性好。

This paper describes an indirect reversed phase ion pair chromatographic separation and UV indirect photometric detection of and S 2O 2- 3 and I - by pre column derivatization with Hg EDTA to form their corresponding ternary complexes EDTA Hg S 2O 3 and EDTA Hg I for the first time. On a Zorbax ODS column with a mobile phase of methanol water we have studied the influences of the ion pair TBA + concentration, pH value, the addition of EDTA, the concentration of organic modifier and ionic strength. In our experiments, the addition of EDTA had a notable effect on retention and peak shape. So the best chromatographic conditions are:methanol∶water=23∶77(V/V), the ion pair reagent TBA +3.0 mmol/L, EDTA 1.0mmol/L, NaNO 3 2.0 mmol/L and buffer solution KH 2PO 4 Na 2HPO 4(pH 7.0). The eluate is monitored by a UV detector operated at 254 nm and the detection limits of S 2O 2- 3 and I - are 61 1 ng and 37 6 ng respectively. Good linear relationships between the peak area (Y) and the amount of anion ions (X) with r=0 9851 and 0 9892, respectively, are obtained. Interference of some ions is also studied. The method is both convenient and selective. It has already been used for the determination of I - in kelp and the results are satisfactory. The amount of I - in kelp is 0 0183% .