以毛細管柱氣相層析法快速分析市售酒精飲料中乙醇含量   全文下載

A Rapid Method for Determination of Ethanol in Alcoholic Beverages Using Capillary Gas Chromatography

本研究建立了直接注入（direct injection）氣相層析分析市售酒精性飲料中乙醇含量之快速定量方法。以極性之megapore CP-Wax 58 CB 管柱（30 m × 0.53 mm）分析定量酒精性飲料中乙醇含量，選擇水溶性之乙?（acetonitrile）為內標準，乙醇之最低定量濃度（limit of quantitation, LOQ）為0.5 μg／mL左右。添加乙醇50及100 mg 於0.5 mL之紅酒及成士忌中，其回收率分別為99~104%及99~101%，變異係數均在3.4%以下，顯示直接注入法之精密度相當高，酒液檢體樣品，加入適當量之內標準溶液混合均勻後，即可直接注入氣相層析儀中分析，簡單又快速。本研究方法與AOAC法（AOAC 969.12及920.57）並無顯著差異，但精密度高於上述二公定法。以本方法分析市售不同廠牌之酒精性飲料，包括蒸餾酒12件及非蒸餾酒14件，共26件之乙醇含量。結果顯示，蒸餾酒，165.2 ± 4.9~415.7 ± 7.6 mg／mL；非蒸餾酒28.2 ± 0.8~141.2 ± 4.9 mg／mL，透過本方法之測定，亦可將樣品中之乙醇含量從重量百分濃度（%, w／v）轉換成較常使用之體積百分濃度（%, v／v），即（%, w／v） = 0.814 （%, v／v），此關係式之相關係數R2在0.999以上。"

A simple and rapid method was developed to determine ethanol content in alcoholic beverages using megapore polar column (CPWax 58 CB, 30 m ¥ 0.53 mm) with direct injection gas chromatography. Contrary to packed GLC method, distillation and/or stepwise dilution of samples were not necessary by the method developed in this study. Ethanol in sample was injected directly into GC for analysis, after adding suitable amount of internal standard, acetonitrile solution. Using this method, less than 8 min was required to obtain result since sample preparation, and the limit of quantitation (LOQ) was about 0.5 µg/mL. Recovery studies were performed using 0.5 mL of red wine and whisky. Each was spiked with ethanol at 50 and 100 mg, respectively. The recoveries were found in the range of 99~104% and 99~101%, respectively. The coefficients of variation were less than 3.4%. Comparisons of the AOAC method (AOAC 969.12 and 920.57) with current method showed no significant difference. These results suggested that precision of direct injection GC method was higher than that of AOAC methods. Several commercial alcohol beverages, including distilled and nondistilled spirits, were analyzed by the current method. The ethanol content of distilled and non-distilled spirit were found as: 165.2 ± 4.9~415.7 ± 17.6 and 28.2 ± 0.8~141.2 ± 4.9 mg/mL, respectively. Using this GC method, we could change the concentration in gravimetric percentage (%, w/v) to volumetric percentage (%, v/v) by the equation (%, w/v) = 0.814 (%, v/v) with linear coefficient R2, higher than 0.999. 本研究建立了直接注入（direct injection）氣相層析分析市售酒精性飲料中乙醇含量之快速定量方法。以極性之megapore CP-Wax 58 CB 管柱（30 m × 0.53 mm）分析定量酒精性飲料中乙醇含量，選擇水溶性之乙腈（acetonitrile）為內標準，乙醇之最低定量濃度（limit of quantitation, LOQ）為0.5 µg／mL左右。添加乙醇50及100 mg 於0.5 mL之紅酒及成士忌中，其回收率分別為99～104%及99～101%，變異係數均在3.4%以下，顯示直接注入法之精密度相當高，酒液檢體樣品，加入適當量之內標準溶液混合均勻後，即可直接注入氣相層析儀中分析，簡單又快速。本研究方法與AOAC法（AOAC 969.12及920.57）並無顯著差異，但精密度高於上述二公定法。以本方法分析市售不同廠牌之酒精性飲料，包括蒸餾酒12件及非蒸餾酒14件，共26件之乙醇含量。結果顯示，蒸餾酒，165.2 ± 4.9～415.7 ± 7.6 mg／mL；非蒸餾酒28.2 ± 0.8～141.2 ± 4.9 mg／mL，透過本方法之測定，亦可將樣品中之乙醇含量從重量百分濃度（%, w／v）轉換成較常使用之體積百分濃度（%, v／v），即（%, w／v） = 0.814 （%, v／v），此關係式之相關係數R2在0.999以上。