利用固相萃取進行鉻酸作業環境分析方法

The Analysis of Chromate Acid in the Workplace Environment by Solid Phase Extraction

動物實驗或流行病學研究都顯示六價鉻為致癌物質，在工業衛生與環境保護都相當的重視此一問題。傳統的六價鉻分光光譜分析容易受樣品中共存物質的干擾，本研究採用強陰離子交換樹脂固相萃取將六價鉻與其他干擾物質分離，再以分光光譜定量六價鉻。研究結果顯示最佳化的六價鉻固相萃取條件為：使用 1000 mg 0.14meq/g 強陰離子交換樹脂固相萃取管，並以 10 mL 0.05M (NH4)2SO4/0.05M NH4OH 萃取溶液，9 mL 0.5M (NH4)2SO4/0.1M NH4OH 洗滌溶液，而溶液流率則為 8.0 mL/min。分析檢量線範圍在每樣品 3.3~66µg 六價鉻，其線性相關係數為 0.9999，而偵測極限為每樣品 0.073 µg 六價鉻。在相當於 0.5, 1 與 2 倍容許濃度，六重複濾紙添加樣品分析變異係數（CVa）為 5.3%，而三濃度樣品平均回收率為 81.9%。以上結果符合勞工安全衛生研究所「作業環境有害物採樣分析參考方法驗證程序」之規範，可建議提供認可實驗室參考使用。

The health hazard attributed to hexavalent chromium, Cr(VI), is an important issue in the area of environmental health, industrial hygiene and environmental protection research due to its human carcinogenesis characteristics. Traditional analysis of Cr(VI) based on the diphenylcarbazide-induced spectrophotometric method has a serious deficiency due interferons in the sample. In this study, the strong-anion exchange solid-phase extraction (SAE-SPE) method was applied to remove the interferons from Cr(VI) followed by the spectrophotometric determination of Cr(VI). Results of the study indicated that optimized solid phase extraction conditions occurred when using 10 mL 0.05 M (NH4)2SO4/0.05 M NH4OH solution for ultrasonic extraction and then transferring 3.0 mL of the extraction solution to an SAE-SPE tube, followed by the elution of the Cr(VI) ions from the SAESPE tube by a 9 mL of 0.5 M (NH4)2SO4/0.1 M NH4OH solution, where the elution flow rate was set at 8 mL/min. The calibration curve range was 3.3-66 μg per sample, where the correlation coefficient (r) was 0.9999 and the method detection limit (MDL) was 0.073 μg per sample. The analytical coefficient of variance (CVa) and the mean recovery rate were 5.3% and 81.9%, respectively, for samples at concentration levels equivalent to 0.5, 1 and 2 times the permissible exposure level of Cr(VI) at the workplace.