巧克力中重金屬檢驗方法開發暨鉬干擾鎘分析之研究   全文下載

Development of an Analytical Method for Heavy Metals in Chocolate and the Study on Molybdenum Interference in Cadmium Analysis

巧克力為大眾喜愛之食品，可可豆為其原料，可可豆之生長環境及加工過程會影響終產品巧克力中重金屬含量。我國衛生福利部公告修正「食品中污染物質及毒素衛生標準」，增訂巧克力及可可粉中重金屬鎘之限量，自115年起實施。本研究採酸輔助之加壓式或密閉式微波消化搭配感應耦合電漿質譜儀（Inductively Coupled Plasma Mass Spectrometer, ICP-MS）分析，同步建立巧克力中砷、鎘、汞及鉛之檢驗方法。由於鉬氧化形成氧化鉬與鎘具有相同質荷比，本研究另分別探討及建立利用ICP-MS氦氣模式及感應耦合電漿串聯質譜儀（Inductively Coupled Plasma Tandem Mass Spectrometer, ICP-MS/MS）氧氣模式之氣體參數，來評估定量分析時鎘受到氧化鉬干擾之影響。結果顯示ICP-MS於4 mL/min氦氣流速下，檢體中鉬含量需為鎘之250倍以上才可能影響鎘之準確性，此時可以ICP-MS/MS氧氣模式進行鎘含量之確認。於空白巧克力檢體中分別添加0.02及0.1 mg/kg之各重金屬元素執行添加回收測試，以ICP-MS氦氣模式進行分析。結果顯示，砷、鎘、汞及鉛平均回收率介於92.5-111.3%，變異係數介於1.3-9.9%。本檢驗方法之定量極限，於砷、鎘、汞及鉛皆為0.02 mg/kg。本研究所建立之檢驗方法符合現行檢驗趨勢，且準確性及精密度良好。

Chocolate is a popular food and cocoa beans are used as raw materials. The growth environment and processing of cocoa beans affect the heavy metal contents in the final chocolate products. The Ministry of Health and Welfare in Taiwan announced amendment of the“Sanitation Standard for Contaminants and Toxins in Food”to add cadmium limits in chocolate and cocoa powder, which will be implemented starting 2026. This study used acid-assisted autoclave digestion or closed style microwave digestion, combined with ICP-MS analysis to establish a testing method for arsenic, cadmium, mercury and lead in chocolate simultaneously. To address the interference of molybdenum oxide with cadmium detection due to the same mass-to-charge ratio, this study evaluated the helium mode in ICP-MS and the oxygen mode in ICP-MS/MS. Results showed the accuracy of cadmium quantification may be affected only if the molybdenum content in the sample was higher than 250 times that of cadmium by ICP-MS at a helium flow rate of 4 mL/min. In this case, ICP-MS/MS with the oxygen mode could be used to confirm the cadmium content. Blank samples were spiked with As, Pb, Cd, and Hg at levels of 0.02 mg/kg and 0.1 mg/kg, respectively, and the recoveries of the four elements were between 92.5% and 111.3% with the coefficients of variation of 1.3% to 9.9%. The limits of quantification for the four elements were all 0.02 mg/kg. The method established in this study showed good accuracy and precision and aligned with the current testing trends.