Straightforward Determination of Hexavalent Chromium by Ion Chromatography  

Generally speaking, hexavalent chromium or Cr(VI) is classified as allergenic, carcinogenic and extremely toxic, and is subject to strict monitoring. Cr(VI) can occur in various concentrations in different areas, e.g., drinking water, toys and textiles. Metrohm has developed ion chromatography determination methods for determining Cr(VI) in various concentration ranges (ng/L to mg/L) with inline sample preparation techniques for various matrices. More information on these applications is available from Metrohm.

Application 1: Chromium(VI) in Mineral and Drinking Water according to EPA 218.7 

When released in nature, Cr(VI) is a highly toxic contaminant of drinking water. Even the smallest quantities are hazardous to human health.    

Even though the RoHS Directive severely has restricted the use of Cr(VI) compounds in Europe since 1 July, 2006, chromate nonetheless remains a widespread pollutant in the environment. Chromium is still used in the manufacture of batteries and stainless steels, among other things.

Some pigments formerly used in dyes also contained Cr(VI) compounds. These chromate pollutants appear in the environment when decontamination is done improperly. The carcinogenic Cr(VI) finds its way into the soil, and over time also into our water.    

The EU limit value for total chromium, which corresponds to both the WHO limit value and to the German Drinking Water Ordinance, is still set at 50 µg/L. Whether to institute a considerable reduction in this limit value is currently under discussion. 

Metrohm has developed an exceptionally sensitive ion chromatography method for the detection of Cr(VI), with a limit of determination of less than 0.02 µg/L Cr(VI). The application is also in compliance with the limit value stipulated to EPA Standard 218.7.

If required, the sample can be prepared for injection using Inline Ultrafiltration in an automated sequence. Detection takes place by means of post-column reaction with 1,5-diphenylcarbazide and subsequent detection at 530 nm. The procedure is controlled using the intelligent ion chromatography software MagIC Net. 

Application 2: Chromium(VI) in Toys according to DIN EN 71-3...

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