New chrome VI method published

An updated version of BS EN ISO 17075, the internationally recognised method for the analysis of chrome VI in leather, was published in early February 2017. The updates see the method being split into 2 parts; part 1 being the colorimetric method (technically unchanged from the current version of the method) and part 2 using a new technique – Ion Chromatography.

 

ISO 17075-2:2017(E) Ion Chromatography is considered an ‘improved analytical technique’.  LASRA testing can confirm that the Chemical determination of chromium (VI) content in leather via Chromatographic method is found to be an improvement over the previous method of determination. This method can be used with a high degree of confidence.

 

Findings

  • The chromatographic method is robust with high repeatability.
  • High linearity and accuracy were found. All recoveries were within the range of 90-110% recommended for non-regulated products. All values are between the 80-120% recovery rate specified by the draft ISO method.
  • Changes were made to the recommended chromatographic conditions stated in the amendments of the method, notably; more concentrated mobile phase, higher flow rate and a longer column. This gave an improved resolution, less tailing and a clear separation in retention time from the solvent peak when compared to the recommended conditions as used on our HPLC system.
  • This chromatographic method addresses a number of difficulties that were present in the previous ISO method for CrVI detection (now IS0 17025-1), such as interference from the colour of the leather extracts.

 

We are currently requesting addition of this chromatographic method to our IANZ scope, so that it may replace the previous method.

 

Figure – Chromatographic detection of CrVI in a CrVI spiked sample