New suppressor technology improves trace level anion analysis with carbonate–hydrogencarbonate mobile phases

• Published in: Journal of Chromatography A Vol. 956; no. 1; pp. 47 - 51
• Main Authors: Douglas, Derick R., Saari-Nordhaus, Raaidah, Despres, Philippe, Anderson, James M.
• Format: Journal Article Conference Proceeding
• Language: English
• Published: Amsterdam Elsevier B.V 17.05.2002; Elsevier
• Subjects: Analytical chemistry; Anions - analysis; Bicarbonates - chemistry; Carbonates - chemistry; Chemistry; Chromatographic methods and physical methods associated with chromatography; Exact sciences and technology; Inorganic anions; Other chromatographic methods; Sensitivity and Specificity; Ion chromatography; Mobile phase composition; Inorganic anions; Trace analysis; Phosphates; Drinking water treatment; Chemical analysis; Chlorination; Phase composition; Sodium Carbonates; Nitrites; Nitrates; Mobile phase; Sulfates; Electrochemical detector; Ozonization; Inorganic anion; Conductometry; Halides; Sodium Hydrogencarbonates; Ion suppressor; By product; Quantitative analysis
• ISSN: 0021-9673
• DOI: 10.1016/S0021-9673(02)00038-9

Sodium carbonate–hydrogencarbonate mobile phases are preferred over sodium hydroxide for anion analysis by suppressor-based ion chromatography (IC). Unlike hydroxide, carbonate–hydrogencarbonate has strong eluting power and its buffering capacity can be used as a selectivity tool for controlling separations. However, carbonate–hydrogencarbonate mobile phases fell out of favor for trace level analysis because the carbonic acid suppressor effluent has some background conductivity, which reduces sensitivity compared to sodium hydroxide. This paper describes a new suppressor technology that improved anion analysis with carbonate–hydrogencarbonate mobile phases. In addition to converting the carbonate–hydrogencarbonate buffer to carbonic acid like other traditional IC suppressors, the new DS-Plus suppressor also removed carbonic acid from the suppressor effluent. Anions are now detected in water background, just like when using sodium hydroxide as the mobile phase. The lower background conductivity improves sensitivity and reduces detection limits. The water-dip often seen with conventional suppressors is greatly reduced, improving fluoride quantification.