Anions & Cations




For the detection of anions in aqueous, water-miscible liquids or water-soluble solids, we use the anion chromatography (HPIC – High Performance Ion Chromatography) as well as potentiometric methods.

Within the ion chromatography anions are separated on a stationary phase of a polymer/divinylbenzene with a low capacity of functional groups (quaternary ammonium base) by use of a mobile phase. After suppression of the basic conductivity by a suppressor column the detection is usually done with a conductivity measuring cell. In addition UV/Vis detectors and amperometric detectors are used for detection.

The potentiometry is based on the detection of an ion concentration by using an ion sensitive electrode against a reference electrode or a titration.

Anions that are routinely determined include fluoride, chloride, bromide, iodide, nitrite, nitrate, phosphate, and sulfate. Also many organic anions such as formate, acetate, benzoate or oxalate are detectable.

The quantification of bound halogens (fluorine, chlorine, bromine and iodine) can be found under halogen analytics.

Which concentrations can be determined?

Anions can be analyzed as major, minor and trace component. Limits of quantification of a few mg/kg are possible depending on the sample matrix.

Which sample matrix can be analyzed?

All liquid and water-soluble matrices can be analyzed.

What are typical tasks?

  • Anion-determination of aqueous solutions from environmental analytics
  • Anion-determination of alkaline or acidic solutions from electroplating, petrochemistry, food industry

Which sample quantity is required for the analysis?

Anions as major component: ≥ 1 ml
Anions as trace component (few mg/L): 1-10 ml

Which methods are available?

  • Ion chromatographic detection
  • Direct potentiometry
  • Potentiometric titration
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