A Better Way to Measure Cr(VI)
While the standard technique for detecting hexavalent chromium, or Cr(VI), has improved over the years with the addition of ion chromatography (IC) coupled to UV/visible spectrophotometry, the EPA published methods still rely upon reaction-based chemistry which are prone to interferences and varying reaction kinetics in complex matrices. Any experienced analytical chemist will tell you that direct measurement of a contaminant is always preferable to relying upon the reaction of the target analyte with another chemical for accurate quantitation. Since there is no EPA method that utilizes direct measurement for Cr(VI), most environmental professionals believe that UV-Vis is the best the labs can do, however this is simply not true.
For decades, Cr(VI) has been classified as a carcinogen when inhaled as dust or particulate, making it a problematic worker safety hazard potentially affecting over 500,000 individuals per year. Because of its extensive use in dyes, wood preservatives, anti-corrosion products, and formation during electroplating, it is not hard to find incidences of contamination in the natural environment as well. The ability to detect hexavalent chromium at trace levels and free from common interferences like organic acids, molybdenum, iron, and other elements, is crucial to the success of the project.
By coupling IC to ICP-MS, the most widely accepted technique for accurate measurement of trace metals in complex matrices, not only can BAL achieve a direct measurement of Cr(VI) and separate out interferences, the achievable detection limits are in many cases two orders of magnitude lower than the most recent published EPA methodology. By virtually eliminating potential bias in the data, BAL’s method for measuring Cr(VI) ensures that remedial investigations and determinations of monitoring exceedances are based upon the best available science and superior data quality. Contact us today to learn more.