以石墨爐電熱式原子吸收光譜儀法測定地下水中砷含量之鹽分干擾

The Salinity Interference for the Determination of Arsenic Content in Groundwater by Graphite Furnance Atomic Absorption Spectrometric Analysis

江漢全(Hann-Chyuan Chiang) ； 劉柏克(Po-Ke Liu) ； 張昭駿(Chao-Chun Chang) ； 楊傑富(Chieh-Fu Yang)

《環境保護》 25卷1期 (2002/06) Pp. 42-53

https://doi.org/10.30017/EP.200206.0005

摘要

地下水中砷含量之測定技術可應用於地下飲用水的安全控制、評估其對人體及生物毒性以及供政府進行污染防治決策參考。目前以石墨爐電熱式原子吸收光譜儀法(graphite furnace atomic absorption spectrometric method, GFAAS)及氫化物產生式原子吸收光譜儀法(hydride generation atomic absorption spectrometric method, HGAAS)最常被使用，在一般的情形下，GFAAS法之精密度及準確度均高於HGAAS法，且GFAAS法具有水樣用量少，不需添加濃鹽酸及氫硼化鈉試劑，分析過程不繁複及較少環境污染等優點，應為較佳選擇，然而針對高鹽分污染之地下水樣，則往往會對GFAAS法之原子吸收光譜造成嚴重干擾。由於台灣地區地下水鹽分偏高者不少，因此，本研究探討一些鹽分相關的水質參數，如E.C、陰離子Cl(上標 -)、SO4(上標 2-)，陽離子Ca(上標 2+)、Mg(上標 2+)、Na(上標 +)、K(上標 +)等對GFAAS法分析砷之影響，並發展一個初步的判斷程序，以供選用GFAAS法或HGAAS法之用。本研究結果顯示，硫酸鹽之干擾效應最強，建議地下水樣之E.C.在1008μS/cm以上或硫酸鹽濃度在131㎎/L以上時，就不宜選用GFAAS法測定地下水樣中之砷含量。

關鍵字

地下水 ； 砷含量 ； 石墨爐電熱式原子吸收光譜儀法 ； 鹽分干擾

並列摘要

The technology to measure the arsenic content in groundwater is important for the controlling of drinking water safety, the evaluation of the possible toxicity for human and organisms, and the establishment of the strategy of the pollution prevention of governments. The usual methods for determining of arsenic content in groundwater samples are graphite furnance atomic absorption spectrometric method (GFAAS) or hydride generation atomic absorption spectrometric method (HGAAS). The previous research reported that the precision and accuracy of the GFAAS method are better than those of the HGAAS method except for groundwater samples with high salinity. The GFAAS method also shows that it is a better choice than the HGAAS method due to some advantages including small sample size, no dangerous chemicals such as concentrated HCl and NaBH4 required, simple analytic procedure and minimum environmental pollution. However, it is interesting to note that high salinity in groundwater samples is popular in Taiwan. Therefore, we discussed some water quality parameters related salinity interference such as electrical conductivity (E.C.), cations (Ca(superscript 2+), Mg(superscript 2+), Na(superscript +), K(superscript +)), and anions (Cl(superscript -), SO4(superscript 2-)), and developed a procedure to primarily judge the selection of GFAAS or HGAAS method for determination of arsenic content in groundwater samples. The result shows that the sulfate ion SO4(superscript 2-) demonstrate the strongest interference influence on determining of As in water samples by GFAAS method. According to the results from the analysis of groundwater samples, it is suggested that when E.C. above 1008 μS/cm or sulfate concentration over 131 mg/L, the GFAAS method is not an appropriate method to analyze those groundwater samples.

並列關鍵字

Groundwater ； Arsenic content ； Graphite furnance atomic absorption spectrometric method ； Salinity interference