Determination of Airborne Hexavalent and Trivalent Chromium
Date Issued
2005
Date
2005
Author(s)
Wu, Yi-Hua
DOI
zh-TW
Abstract
Since 1797, L. N. Vauquelin discovered chromium. It was used in industries until now. Chromium is used widly in industries. AS a result, the occupational exposure to chromium frequently occurs in work place. Trivalent chromium and hexavalent chromium are the predominant chromium species in the natural environment. Trivalent chromium is known to be an essential trace element, on the other hand, haxavalent chromium is determined as a carcinogenic substance. Due to the difference in the human health effect between trivalent and hexavalent chromium . It is obvious that speciation is necessary.
Occupational Safety and Health Administration (USA, OSHA) will decrease hexavalent chromium PEL-TWA from 0.1 mg/m3 to 0.001mg/m3 in workplace air. And Council Labor Affiar in Taiwan (CLA) considers to follow this step.Before decresing the regulation level, we should consider that is analyse method sensitivity enough? It’s the important part of occupational health. The UV/VIS of traditional speciation methods is usually be influenced by the cations in workplace air, and results in over estimation of occupational exposure assessment. The NIOSH METHOD 7703 uses strong anion exchange-solid phase extract cartridges to control cation confounding to get a better result.After the modification of NIOSH METHOD 7703, MDL is 0.0022 μg/mL and adaptable sample concentration range is 0.11~6.67 μg/mL. Just equal to field concentraction grange 0.11~6.95 mg/m3 of sampling for 8 hours at 2 mL/min flow rate. This method can also separate trivalent chromium from CrO42- clearly.
In addition, UE/HPLC/ICP-MS equipped with anion exchange column to speciate Cr(III) and Cr(VI) in the μg/L level. H2 and He were used as collision gas in the ICP-MS detection to reduce the interference of multiatomic ions for Cr-52 ion monitoring. The results indicated that the He mode provided better reduction of multiatomic ion interference, where the calibration curve is between 1 to 100 μg/L. Trivalent chromium and hexavalent chromium’s detection limits are 0.21 μg/L and 0.26 μg/L. In filter spike test, we spiked Cr(III) and Cr(VI) on PVDF filters that were soaking in 1 M NaOH at the same time. As each sample contains below 250 ng, both of Cr(III) and Cr(VI) recovery can reach to 88% and 103%. The result indicated PVDF filter is better than PVC and MCE filter.
Subjects
六價鉻
固相萃取
紫外光分光光度計
感應耦合電漿質譜儀
氦氣碰撞模式
hexavalent chromium
Strong-Anion Exchange Solid Phase Extraction
UV/VIS
HPLC
ICP-MS
Helium collision mode
SDGs
Type
thesis
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