飲料中磷酸檢驗方法之探討

IONIC CHROMATOGRAPHIC STUDIES ON PHOSPHORIC ACID

磷酸之定量方法很多種，經比較後，以離子層析（Ion Chromatograph）法所需之前處理和所使用的試藥最少，可快速分析。飲料檢體經超音波振盪再以濾膜過濾後，即可用離子層析儀分析，本實驗使用陰離子層析管（Ionpac As4）導電度計檢測器（Conductivity Detector）。添加三種不同濃度標準品於樣品中，使其最終濃度為0.1，0.5及1.0mg/ml，測其回收率，各種濃度在三重覆下，其平均固收率分別為101.7%，1l0.0%及99.9%，總平均回收率為103.9%。由結果顯示，本檢驗方法其回收率及再現性均良好。又利用本檢驗法檢驗市售飲料50件，包括可樂28件、果汁6件、沙士、汽水12件，其它（運動、休閒）飲料4件，其中可樂28件檢體皆符合限量標準0.6g/kg以下。

Numerous methods have been used to detect the phosphoric acid in beverage. Among them ionic chromatographic (IC) method takes advantages of less reagent for pretreatment and less time for analysis. Through Ultrasonic 'degas and filtration, the drink samples are ready for I.C. analysis. In this study, three concentrations of phosphoric acid, 0.1mg/ml, 0.5mg/ml and 1.0mg/ml, in drink samples were used to detect the recoveries. The average recoveries in triplicate were 101.7%, 110.0% and 99.9% respectively and the total average recovery was 103%. These results indicated that I.C. method could get good recovery and reproducibility. 50 drink samples including 28 cola drinks, 6 kinds of fruit juice, 12 sarsparilla drinks and 4 other drinks (sport, safari club drink) were detected the phosphoric acid contents by I.C. method. All 28 cola samples didn't exceed the legal allowance (0.6g/kg).