Mining Publication: Field Method for the Determination of Insoluble or Total Hexavalent Chromium in Workplace Air
Original creation date: September 2004
National Institute for Occupational Safety and Health method 7703 is a portable field procedure for the analysis of workplace air filter samples for hexavalent chromium (CrVI) content immediately after the samples are collected. The field method prescribes CrVI extraction from air filter samples with an ammonium sulfate/ammonium hydroxide extraction buffer using ultrasonic extraction (UE). Strong anion-exchange solid-phase extraction (SAE-SPE) is then used to separate CrVI from trivalent chromium and other interferences. Portable spectrophotometric measurement of CrVI is then conducted using the 1,5-diphenylcarbazide (DPC) method. However, it has been found that the ammonium extraction buffer does not adequately bring insoluble CrVI compounds into solution during the UE process. Thus, it was deemed necessary to modify the field method so that it would provide acceptable recoveries for insoluble CrVI compounds. To this end, a more alkaline extraction solution - sodium carbonate/sodium bicarbonate buffer - was investigated. The modified procedure using the highly alkaline extraction solution was demonstrated to be compatible with SAE-SPE cartridges when determining insoluble CrVI in air filter samples. It was found that the carbonate/bicarbonate buffer was equally effective for complete dissolution of both insoluble and soluble forms of CrVI. Furthermore, the modified procedure met desired performance criteria established for air sampling and analytical methods.
Authors: KJ Hazelwood, PL Drake, KE Ashley, AD Marcy
Peer Reviewed Journal Article - September 2004
NIOSHTIC2 Number: 20025410
J Occup Environ Hyg 2004 Sep; 1(9):613-619
See Also
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- Characteristics of Fugitive Dust Generated from Unpaved Mine Haulage Roads
- Determining the Spatial Variability of Personal Sampler Inlet Locations
- Evaluation of Sequential Extraction Procedures for Soluble and Insoluble Hexavalent Chromium Compounds in Workplace Air Samples
- A Handheld Electrostatic Precipitator for Sampling Airborne Particles and Nanoparticles
- Instrumentation for Diesel Particulate Matter Emissions Research
- A Review of Occupational Silica Exposures on Continuous Mining Operations
- Rock Dusting Considerations in Underground Coal Mines
- Sonic Anemometer Airflow Monitoring Technique for Use in Underground Mines
- Use of Vacutainers for Collection of Mine Atmosphere Samples
- Content source: National Institute for Occupational Safety and Health, Mining Program