Analyzing Transition Metals by Ion Chromatography

Testing transition metals in food, water, and drugs

The 38 transition metals have a distinguishing characteristic—valence electrons present in more than one shell that combine with other elements. Transition metals often exhibit several common oxidation states. When used or disposed of incorrectly, they can contaminate soil or water. Several studies have linked specific transition metals to various diseases.

Traditional methods for transition metal detection can have limited sensitivity and solute vaporization interferences. Ion chromatography is ideal for separating transition metals, with the ability optimize or alter separation simply changing eluents.

Regulatory information

Various regulatory agencies have set guidelines for quantities of transition metal elements in food, water, and pharmaceutical products. See below for some examples.

  • EPA: In 1991, established an MCLG of 1.3mg/L for copper in drinking water to protect against adverse gastrointestinal tract effects. Public drinking water supplies cannot exceed 5 ppb of cadmium.
  • FDA: Limits the acceptable amount of metals in food and drug products. For example, the limit for cadmium in food coloring is 15 ppm.
  • WHO: Established a provisional drinking-water guideline of 2mg/L for copper, among other guidelines.
  • USP: Sets mg/g limits for elemental impurities in drug products, including transition metals. Examples include limits of 0.25mg/g for cadmium, 1.0mg/g for palladium, 6.0mg/g for nickel, and 13mg/g for copper.

Example application notes