Analysis of Common Anions by Unsuppressed Conductivity

Poster Presentation

Prepared by P. Macek1, J. Mott2, C. Burkhardt3, H. Edwards3, M. Nishimura1
1 - Shimadzu Scientific Instruments, Inc., 7102 Riverwood Dr., Columbia, MD, 21046, United States
2 - Shimadzu Scientific Instruments, Inc., Midwest Regional Office, 8052 Reeder Street, Lenexa, KS, 66214, United States
3 - Radford University, Department of Chemistry, PO Box 6949, Radford, VA, 24142, United States

Contact Information: [email protected]; 804-432-8912


Common anions are typically analyzed by suppressed conductivity. Most analytical chemists are familiar with the technique. Suppressed conductivity works well but usually requires a dedicated ion chromatograph. Demand for anion analysis is limited in some markets. In many smaller laboratories, the ion chromatograph sits idle for much of the time. The same is true of the HPLC; it sits idle in many smaller labs. Combining the inorganic and organic LC functions will allow smaller labs to make better use of scarce resources by performing both analyses on one instrument. Additionally, connection to a uv/vis detector in series allows analysis and quantification of nitrate and nitrite in the presence of chloride at a high concentration; high concentration chloride is frequently a problem when analyzing nitrate and nitrite. Standard Methods 4110, Section C suggests conditions for analysis using unsuppressed conductivity. By using a less conductive mobile phase coupled to a different column, it may be possible to achieve or possibly even to improve upon the detection limits and separation shown in Method 4110 C. Furthermore, because there is no suppressor in line, it is possible to connect to UV/Vis, fluorescence and other LC detectors with little more than a column and mobile phase change. That flexibility allows smaller labs to set up a true dual purpose instrument. An additional benefit is that suppressors are expensive and somewhat fragile. Not having to use a suppressor may save cash-strapped small laboratories considerable expense.