|Abstract: || 金屬污染物質的特性是金屬進入環境中，就永久存在環境中而不被分解，存在於環境中金屬經過各種途徑進入人體內，大氣中的金屬多經呼吸道進入體內，亦可能間接的污染食品再經口進入人體內。多模式進樣系統 (multimode sample introduction system; MSIS) 可進行霧化模式 (nebulization mode)、蒸氣生成模式 (vapor generation mode) 及同時測定蒸氣生成及霧化之雙模式 (Dual mode)。本研究利用微波消化法前處理後以氫化物生成 (hydride generation; HG) 技術配合感應耦合電漿放射光譜儀 (inductively couple plasma optical emission spectrometry; ICP-OES) 對特殊營養食品中砷 (As) 及汞 (Hg) 元素進行測定。研究結果顯示分析物於14% HNO3 溶液中加入 20% (m/v) 碘化鉀溶液 1.0 ml並與1.7% 硼氫化鈉 (NaBH4) 產生易揮發之共價氫化物，可提升砷及汞之訊號強度。此外，樣品於微波消化程序產生之揮發性氮氧化物 (volatile nitrogen oxides) 對砷及汞之測定造成干擾，加入30% 過氧化氫 (H2O2) 1ml，並再次微波消化可使干擾最小化。添加樣品回收率範圍在91.0% ~108.8% 及RSD範圍在0.9% ~ 5.2%。偵測各種特殊營養食品中有毒有害之元素之砷、鉛 (Pb)、鎘 (Cd) 及汞與礦物質元素，如鈉 (Na)、鈣 (Ca)、鎂 (Mg)、鉀 (K)、磷 (P)、鐵 (Fe)，銅 (Cu) 及硒 (Se)。以感應耦合電漿放射光譜儀分析砷、鉛、鎘、汞、銅及硒均低於偵測極限，為確實檢測其濃度進一步以感應耦合電漿質譜儀 (inductively coupled plasma mass spectrometry; ICP-MS) 檢測。感應耦合電漿質譜儀用於測定砷、鉛、鎘、硒、銅及汞；感應耦合電漿放射光譜儀用於測定鈉、鈣、鎂、鉀、磷及鐵。分析方法通過精密度、準確度及回收率之實驗驗證，於所有情況下均獲得滿意之結果。利用認證參考物質驗證方法之準確性，回收率範圍在93.1% ~ 109.5%。所有有害之元素之濃度均低於聯合國糧農組織及世界衛生組織食品添加聯合專家委員會 (JECFA) 所建議有害之元素每週容許攝取量值 (PTWI)，整體之攝入量非常低，不會對消費者構成任何威脅，且營養元素大多符合商品標示，可提供消費者之營養需求。|
Metal pollutants in the environment through variety ways to intake by human. The main route of exposure to elements is through the diet. Food safety is a worldwide major public concern, and the increasing worry about food safety stimulated research regarding the risk associated with the consumption of food contaminated by heavy metals.The Multimode Sample Introduction System (MSIS), a system that combines the benefits of nebulization and vapor generation in a single device. In this study, we propose a procedure for the determination of arsenic and mercury in special nutrition food after wet digestion of the samples in HNO3 using hydride generation (HG) with inductively coupled plasma optical emission spectrometry (ICP-OES). The effect of acidity from HNO3 (14%) as well as the presence of potassium iodide on the efficiency of hydride generation by reaction with the 1.7% NaBH4 reductant was investigated. Addition of 20% (m/v) KI 1.0 ml can enhance the As and Hg signals. However, As and Hg signals are interfered by volatile nitrogen oxides from digestion procedures with nitric acid on the determination of As and Hg. Addition of 30% hydrogen peroxide (H2O2) 1ml can minimize this interference by microwave digestion. Matrix Spike results show the recovery was 91.0% ~108.8%, RSD (%) was 0.9% ~ 5.2%. The levels of toxic heavy metals including As, Pb, Cd, Hg and mineral elements, such as, Na, Ca, Mg, K, P, Fe, Cu and Se in various of special nutrition food were determined by using ICP-OES. The results of As, Pb, Cd, Hg, Cu and Se detected by ICP-OES were lower than detection limit, therefor, we use ICP-MS to detect the concentration of this metals further. It was found that ICP-MS was better to be used for determination of As, Pb, Cd, Se, Cu and Hg, and ICP-OES was available to used for Na, Ca, Mg, K, P and Fe. The analytical methods were validated by precision, accuracy and recovery experiments, obtaining satisfactory results in all cases. The accuracy of the method was verified by analyzing various certified reference, the recovery was 93.1% ~ 109.5%. Generally concentrations of all analysis heavy metals were lower than provisional tolerable weekly intakes (PTWI) specified by The Joint FAO/WHO Expert Committee on Food Additives (JECFA). Their contribution to the overall intake was very low and thus would not pose any threat to consumers. The nutrition elements were all corresponded with product labeling, and can provide demands of nutrition for consumers.