Sampling and analysis consideration for determination of hexavalent chromium in mainstream and sidestream tobacco smoke
Chromium is present in the environment mainly in the oxidation states (III) and (VI). Airborne hexavalent chromium is a known human respiratory carcinogen and allergen.
A method for determining hexavalent chromium in mainstream and sidestream tobacco smoke is in development. The basis of analytical methods involves extraction of the filter containing 20 cigarette's TAR in alkaline buffer solution, chemical isolation of Cr (VI) ion and detection by ICP and UV visible system.
The particulate matter is extracted from the filter by a pH = 8 buffer solution (NH4)2SO4 0.05 M/NH4OH 0.05 M in a ultrasonic bath. This pH was chosen to reduce the oxidation potential of Cr(VI) and to avoid possible oxidation of Cr(III) to Cr(VI). In order to separate the two oxidation states the solutions are eluted trough a strong anion exchange column with (NH4)2SO4 0.5 M/NH4OH 0.1 M.
After elution the detection is performed by two different techniques:
- A species-selective complex of Cr(VI) with diphenylcarbazide (DPC) was prepared, then extracted into n -hexanol and quantified by UV-visible spectrophotometry.
- The eluted solution is acidified with nitric acid and quantified by ICP system.
Other sampling and separation procedures are under investigation.