抑制型离子色谱法检测水中二氯乙酸和亚硝酸盐分离条件优化

Optimization of separation conditions for the determination of dichloroacetic acid and nitrite in water by suppressed ion chromatography

中文关键词:  响应面法  离子色谱  二氯乙酸  亚硝酸  分离度  优化

英文关键词:response surface methodology  ion chromatography  dichloroacetic acid  nitrite  separation degree  optimization

中文摘要:

      目的 建立基于抑制型离子色谱法同时测定水中二氯乙酸(dichloroacetic acid, DCAA)和亚硝酸盐的检测方法, 并通过响应面法优化其分离条件。方法 采用Thermo Scientific Dionex IonPac? AS19型阴离子交换柱, 以DCAA和亚硝酸盐的分离度为核心评价指标, 首先通过单因素试验考察柱温、DCAA浓度、淋洗液浓度3个关键因素对分离效果的影响规律, 在此基础上, 采用Box-Behnken中心组合设计构建响应面模型, 深入探究各因素间的交互作用并确定最优分离条件。结果 经响应面法优化得到的最佳分离条件为: 柱温25 ℃、DCAA质量浓度1000 μg/L、淋洗液浓度6 mmol/L(亚硝酸盐质量浓度固定为100 μg/L作为实验背景)。在该优化条件下, DCAA与亚硝酸盐的分离度为2.71, 满足检测过程中对组分有效分离的要求。方法学验证结果显示, 该方法在一定浓度范围内线性关系良好(决定系数r2＞0.999), 相对标准偏差小于3.5%, 加标回收率为95%~107%, 表明方法具有较高的准确性和稳定性。结论 本研究优化得到的检测方法能够有效实现水中DCAA和亚硝酸盐的同时准确测定, 操作简便、高效可靠, 适用于实际饮用水中这两种物质的日常监测工作, 为水质安全评估提供了有力的技术支撑。

英文摘要:

      Objective To establish a method for the simultaneous determination of dichloroacetic acid (DCAA) and nitrite in water by suppressed ion chromatography, and optimize their separation conditions through response surface methodology. Methods Thermo Scientific Dionex IonPac? AS19 anion exchange column was used. Taking the separation degree of DCAA and nitrite as the core evaluation index, the effects of 3 key factors (column temperature, DCAA concentration and eluent concentration) on the separation degree were investigated by single-factor experiments. Building upon this, a Box-Behnken central composite design was employed to construct a response surface model, thoroughly exploring the interactions between the factors and determining the optimal separation conditions. Results The optimal separation conditions obtained by response surface methodology were as follows: column temperature 25 ℃, DCAA mass concentration 1000 μg/L and eluent mass concentration 6 mmol/L (with nitrite mass concentration fixed at 100 μg/L as the experimental background). Under the optimized conditions, the separation degree between DCAA and nitrite reached 2.71, meeting the requirement for effective separation of components during detection. Methodological validation results demonstrated good linearity within a certain concentration range (determination coefficient r2>0.999), the relative standard deviations were below 3.5%, and spike recovery rates were 95%-107%. These findings indicated that the method possessed high accuracy and stability. Conclusion The detection method optimized in this study can effectively achieve simultaneous and accurate determination of DCAA and nitrite in water. It is characterized by simple operation, high efficiency and reliability, making it suitable for the routine monitoring of these 2 kinds of substances in actual drinking water. This provides strong technical support for water quality safety assessment.