Comparison of ion chromatographic methods for the determination of organic and inorganic acids in precipitation samples

• Published in: Analyst (London) 1992, Vol.117 (7), p.1137-1144
• Main Author: CHEAM, V
• Format: Article
• Language: English
• Subjects: Analytical chemistry; Chemistry; Chromatographic methods and physical methods associated with chromatography; Exact sciences and technology; Other chromatographic methods
• ISSN: 0003-2654; 1364-5528
• DOI: 10.1039/an9921701137

Three ion chromatographic methods (gradient, ion-exclusion and isocratic) were compared for the determination of organic and inorganic acids in precipitation samples. The gradient method was the best single method allowing determination of all 16 acids of interest. However, it was recommended that a combination of gradient and ion-exclusion methods provided the most reliable results for formic, hydrofluoric and methanesulphonic acids whilst the ion-exclusion method provided the best results for acetic acid and lactic acids. Detection limits for the gradient (0.01-0.08 ppm) and isocratic (0.01-0.25 ppm) methods were comparable for most acids but were lower than for the ion-exclusion method (0.1-0.4 ppm). Precision of results decreased in order from isocratic method through gradient method to ion-exclusion method. Recoveries were near quantitative for all methods except for some organic acids determined by the ion-exclusion method.