以一酵素反應測量液體食品與飲料中銅離子含量   全文下載

Detection of Copper Ions in Liquid Foods and Beverages Based on an Enzymatic Method

本研究開發一種經濟、簡便與靈敏的酵素法測量水液中銅離子含量。因為脫銅的超氧化物歧化?（SOD）成為不具有SOD活性的脫輔基－－超氧化物歧化?（aop-SOD）。可藉含銅水液試樣使aop-SOD恢復SOD活性的現象，估算液中銅離子含量，進而定量樣本中銅的濃度。本研究發現樣品中銅的濃度（從20到80 ppb）與恢復的SOD活性有線性相關（R2 = 0.998），且本方法之銅的檢出極限為20 ppb。此外，一些常見的金屬離子對此反應的干擾效應亦被研究，結果顯示濃度若低於45 μg/mL的這些金屬離子，則對此酵素法沒有干擾效應。此外，由此法獲得的量測數據與感應耦合電漿原子發射光譜分析儀（ICP-AES）的估算數據與非常接近。這酵素分析法可應用於例行測定水液樣品中銅含量的檢測，例如飲料、飲用水與液體食品。而大量樣品時，該法可應用ELISA微量盤偵測儀進行量測（約每小時96個樣品）。

An economic, simple and sensitive enzymatic method for the determination of copper in aqueous samples was proposed in this study. By removal of copper, superoxide dismutase (SOD) becomes apoenzyme SOD (apo-SOD) that has no SOD activity. The amount of copper added can be estimated by the recovery of SOD activity from reconstituted apo-SOD. The concentration of copper in an aqueous sample can thus be determined. A linear relationship (R2 = 0.998) between the concentrations of copper, ranging from 20 to 80 ppb, and the recovered SOD activities was observed. The detection limit for copper in the proposed assay was 20 ppb. Moreover, interfering effects of some common metals on the recovery of SOD activity was evaluated. It showed that the concentrations of these metals less than 45 μg/mL exhibited no interference in the assay. In addition, data obtained from this assay were very close to those estimated by inductively-coupled plasma atomic emission spectrometry (ICP-AES). This enzymatic method can be adapted as a routine assay for the determination of copper in aqueous samples such as beverages, drinking water and liquid foods. The assay can be applied for large number of samples (about 96 samples per hour) on an ELISA microplate reader.