ICP⁃OES法测定水中碳酸根和溶解二氧化碳

Determination of Carbonate and Dissolved Carbon Dioxide in Water by ICP‐OES

为建立一种气态进样的快速测定水样中碳酸根及溶解二氧化碳的电感耦合等离子体原子发射光谱分析方法,对气态进样方式进行改进、设计,采用二氧化碳在线发生装置,利用稀盐酸和待测样液酸化反应生成二氧化碳,使用电感耦合等离子发射光谱测定水样中碳的含量。优化确定酸的种类、酸使用量及仪器中各参数的最佳选择,根据使用体积和释放二氧化碳浓度的关系建立曲线,得到样品中碳酸根及溶解二氧化碳的含量。该方法待测二氧化碳浓度在0~400 mg/L内时呈线性关系,碳酸根的检出限为0.021 mg/L、溶解二氧化碳的检出限为0.077 mg/L。样品加标回收率为98.75%~107.15%,精密度为3.31%~5.78%。该方法对水体中无机碳测定有一定效果,在监测水体中溶解无机碳变化、通量及对其来源分析方面具有应用意义。

A method for rapid determination of carbonate and dissolved carbon dioxide in water samples with vapor generation by inductively coupled plasma atomic emission spectrometry(ICP⁃OES)was developed in this study.Improvements and design modifications were implemented for the gas injection method,incorporat⁃ing an online carbon dioxide generation device.The method involved the acidification reaction of the test sample with dilute hydrochloric acid,generating carbon dioxide,and ICP atomic emission spectrometry was then utilized to determine the carbon content in the water samples.By optimizing the acid type selection,the optimal acid dosage,and the selection of various instrument parameters,a curve was established based on the relationship between the sample volume and the concentration of released carbon dioxide.This curve allowed the determination of carbonate and dissolved carbon dioxide content in the samples.The method exhibited lin⁃earity for carbon dioxide concentrations within 0-400 mg/L,with detection limits for carbonate and dissolved carbon dioxide at 0.021 mg/Land 0.077 mg/L.The recovery rates for spiked samples ranged from 98.75%to 107.15%,and precision fell within 3.31 to 5.78.This method is very effective for the determination of inorganic carbon in water,and has a good application significance in monitoring the change and flux of dissolved inor⁃ganic carbon in water and analyzing its source.