利用谱睿(Pre)在线样品前处理技术检测高碳酸盐基体中阴离子

利用戴安公司全新的谱睿(Pre)在线样品前处理技术,开发了一种柱前在线去除高碳酸盐基体中碳酸盐的方法,解决了以往高碳酸盐基体对其他阴离子测定的影响问题。利用该方法对钢铁洗涤液碳酸钠溶液、固体碳酸钠试剂、商品化碳酸钠淋洗液浓缩液等不同类型的样品分别进行了检测。选择的色谱条件为高容量氢氧化物选择性IonPac AS15阴离子交换色谱柱,淋洗液自动发生装置在线产生KOH进行梯度淋洗,抑制电导检测。该方法在常规离子色谱基础上增加一个输液泵、一个六通阀和一个在线二氧化碳去除器(CRD),提出了不使用浓缩柱作为前处理设备与离子色谱主机之间的接口,而采用大定量环,选取合适的时间窗口这一先进理念。该方法可实现5000 mg/L碳酸盐溶液的在线去除,同时检测出浓度低于50μg/L的氯离子、硝酸根离子、硫酸根离子等阴离子。采用外标法和外延法进行定量,标准曲线线性较好,标准加入回收率为92%~108%。方法具有操作简单、可重复性强、方法新颖等特点,并解决了碳酸根离子对其他阴离子的测定干扰这一离子色谱技术难题。

Determination of Anions in High Carbonate Matrix by Ion Chromatography with Pre Online Sample Preparation Technique

In order to eliminate the interference from high carbonate matrix on the determination of anions by ion chromatography with suppression conductivity detector,a method in which Dionex "Pre" online sample preparation technique was used to remove carbonate matrix before column separation was developed.Sodium sarbonate solution for steel cleaning,solid sodium carbonate and concentrated sodium carbonate eluent were analyzed by this method.The separation between analytes and matrices was obtained using high-capacity of hydroxide-selectivity IonPac AS15 anion separation column.Eluent Generator(EG) was employed to generate KOH eluent online and automatically for gradient elution.An extra pump,a valve with six ports and an online carbon dioxide removal device were added to the system.A brand-new concept of using a large loop instead of concentrator as the connector between ion chromatographic system and pretreatment system was proposed.This technique realized the determination of anions,such as chloride,nitrate,sulfate etc in 5000 mg/L carbonate matrixes with detection limits of 10~50 μg/L for different anions and the recoveries of anions were between 92%~108%.The method provides the advantages of easy-operation,good reproducibility,low operation cost and solves one of most tough problem of interference of high carbonate matrix on determination of anions by ion chromatography.