果汁及果泥飲料中有機酸多重分析方法之開發   全文下載

Developm ent of a Multi-Analytical Method for Organic Acids in Fruit Juice and Fruit Nectar

本研究以果汁及果泥飲料為基質，經前處理後，以離子層析儀（I o n Chromatography, IC）進行分析，並以去離子水及甲醇為移動相溶液，經陰離子交換層析管柱分離後，以電導度偵測器收集訊號進行結果分析。本研究上機後可於45分鐘內良好分離乳酸、醋酸、己二酸、琥珀酸、蘋果酸、順丁烯二酸、反丁烯二酸、草酸及檸檬酸等9項有機酸成分；選用另一管柱則可分析酒石酸。以空白基質添加有機酸以進行準確度、重複性與定量極限之評估，結果顯示，各有機酸之線性範圍，乳酸及醋酸為2.5-5 mg/L，己二酸、琥珀酸、蘋果酸、順丁烯二酸、反丁烯二酸、草酸及檸檬酸為10-100 mg/L，酒石酸為20-50 mg/L，其線性相關係數（r）均大於0.99。平均回收率介於81.9-112.4%，變異係數介於2.4-10.3%，本方法於乳酸及醋酸之定量極限均為12.5 mg/kg；於己二酸、琥珀酸、蘋果酸、順丁烯二酸、反丁烯二酸、草酸及檸檬酸之定量極限均為50 mg/kg；於酒石酸之定量極限為100 mg/kg。後續以8件市售果汁/果泥飲料檢體驗證所建立之檢驗方法適用性，並未有基質干擾之情形，部分檢體檢出含有乳酸、醋酸、蘋果酸、草酸、檸檬酸及酒石酸，而琥珀酸、己二酸、順丁烯二酸及反丁烯二酸則所有檢體均未檢出。

A muti-analytical method for determining 10 organic acids in fruit juice and nectar by ion chromatograph (IC) was developed. The separation was conducted on an anion exchange column with the eluent composed of deionized water and methanol, and detection was carried out by a conductivity detector. Lactic acid, acetic acid, adipic acid, succinic acid, malic acid, maleic acid, fumaric acid, oxalic acid, and citric acid were well separated within 45 minutes. Tartaric acid was analyzed using another column. The recoveries, repeatability and limits of quantification were evaluated by spiking 10 organic acid standards into the blank matrix. The linear ranges were 2.5-5 mg/L for lactic acid and acetic acid, 10-100 mg/L for adipic acid, succinic acid, malic acid, maleic acid, fumaric acid, oxalic acid and citric acid, and 20-50 mg/L for tartaric acid, with all linear correlation coefficients (r) exceeding 0.99. The average recoveries of 10 organic acids were between 81.9 and 112.4%, and the coefficients of variation were between 2.4 and 10.3%. The limits of quantification for lactic acid and acetic acid were 12.5 mg/kg, those for adipic acid, succinic acid, malic acid, maleic acid, fumaric acid, oxalic acid and citric acid were 50 mg/kg, and that for tartaric acid was 100 mg/kg. This method was further applied to 8 commercial samples. The results showed that lactic acid, acetic acid, malic acid, oxalic acid, citric acid and tartaric acid were detected in some samples without matrix interference. However, adipic acid, succinic acid, maleic acid, and fumaric acid were not detected in any of the samples.