含硼盐卤体系中碳酸根和碳酸氢根分析方法改进

Optimization of Determination of CO_3^(2-) and HCO_3^- in Boron-Containing Brine

利用甘露醇法测定硼、双指示剂法测定总碱度,同时借鉴血清中HCO_3^-的检测方法,建立了一种分光光度-滴定分析联用方法,用于准确测定含硼盐卤体系中硼及CO_3^(2-)和HCO_3^-的准确含量。以酚红为显色剂,考察了测定波长、显色剂用量、显色反应温度、pH等测试条件的影响,并从浓度与吸光度的线性关系,检出限及加标回收率等方面进行了系统研究,结果表明:在显色剂用量为1mL,控制pH 8.4,室温下进行显色反应;在波长558nm处,CO_3^(2-)在0~10mmol·L^(-1)内吸光度与浓度有良好线性关系,线性相关系数R^2=0.999 8,检出限为2.53×10^(-3) mmol·L^(-1)。样品加标回收率范围在97.75%~101.76%间,相对误差在-1.67%^-1.95%。该方法简便易行,精密度好,准确度高,优化了共存硼体系中CO_3^(2-)和HCO_3^-含量的测定方法,为含硼盐卤体系中体系碳酸根和碳酸氢根含量的准确测定提供了一种新的方法,对于盐湖卤水的基础研究和实际应用提供了新的思路和实验方法。

Basingthe titration to analyze the total boron,total alkalinityand made references to the determination of serum bicarbonate,we have developed a new method by combining UV spectrophotometry and titration to determine CO3^2- and HCO3^- values accurately in boron-containing brine.The effects of spectrophotometric reaction were studied by analyzing the wavelength,the dosage of chromogenic reagent,temperature and pH,choosing phonel red as chromogenic reagent.The further research was studied by analyzing the linearity between the absorbance and the concentration,the detection limitation,the recovery rate and so on.The results showed that the maximum absorbance peak is at 558 nm.There was a good linear relationship in the ranges of 0～10.0 mmol·L^-1,correlation coefficient R^2=0.999 8.The detection limitation is 2.53×10^-3 mmol·L^-1.The recoveries ranges from 97.75%to 101.76%.The relative standard devivation（RSD）is in the range of-1.67%～-1.95%.The dosage of chromogenic reagent was 1.0 mL.The room temperature was suitable and pH is 8.4.The proposed method is of high accuracy and precision.This method optimized the determination of CO3^2- and HCO3^- in boron-containing brine.The new method provides a new idea and experimental method for the basic research and practical application of brine,has potential to be applied in fundamental research and process development of brine.