离子对色谱测定碱性样品溶液中铬的方法研究

Determination of Chromium in Basic Sample\= Solutions by IonPair Chromatography

提出了两种测定碱性样品溶液中铬的离子对色谱方法。第一种方法将碱性溶液用Ｈ３ＰＯ４中和，流动相采用含有１５ｍｍｏｌ／ＬＮａ２ＳＯ４的１ｍｍｏｌ／Ｌ四丁基氢氧化铵溶液（ｐＨ７）；第二种方法将碱性溶液用ＨＣｌ中和，流动相采用含有２．５ｍｍｏｌ／Ｌ辛胺和１０ｍｍｏｌ／ＬＮａ２ＳＯ４的φ＝６％的乙腈溶液（ｐＨ７）。两种方法均采用４ｍｍ×２５０ｍｍ的硅胶ＮｕｃｌｅｏｓｉｌＣ１８柱作为分离柱。铬的检测限为０．０１ｍｇ／Ｌ，其线性范围在０～０．５ｍｇ／Ｌ。对岩石、沉积物、土壤等地质样品中铬的测定结果与光度法基本相符，且ＲＳＤ（ｎ＝５）≤１．２％

Two ionpair chromatographic methods for the determination of chromium in basic sample solutions are described in this paper. In the first method the basic sample solution is neutralized by phosphoric acid and analyzed by using 1 mmol/L tetrabutyl ammonium hydroxide (TBAH) solution containing 15 mmol/L sodium sulfate (pH 7) as mobile phase. In the second method the basic sample solution is neutralized by hydrochloride acid and mobile phase is 6% acetonitrile solution containing 2.5 mmol/L octyl amine and 10 mmol/L sodium sulfate (pH 7). The detection limits of these two methods are 0.01 mg/L Cr and the linear range is 00.5 mg/L Cr. The methods have been applied to the determination of Cr in rocks, sediments and soils. The results are in agreement with those provided by photometric method with precision of 1.2% RSD(n=5). \=\=