利用高效液相層析法分析嬰兒食品中維生素B1、B2及C檢驗方法之探討

Analysis of Vitamin B1, B2 and C in Baby Foods by High Performance Liquid Chromatography

利用高效液相層析法分析嬰兒（輔助）食品中維生素B1、B2及C之檢驗方法業已建立。前者將檢體加0.1N鹽酸加熱萃取後，加α-amylase酵素水解，去除蛋白質，所得之檢液加含1%鐵氰化鉀之15% NaOH溶液，反應後，加磷酸中和，最後採用螢光檢測液相層析法同時定量分析維生素B1及B2。後者將檢體加偏磷酸－－醋酸溶液，以超音波振盪萃取，過濾後進行高效液相層析。米麩檢體中同時添加維生素B1及B2 2、4、6、9及12 ppm時，維生素B1之回收率為90.83-92.83 %，維生素B2為96.00-99.25%。另外同時添加抗壞血酸（維生素C）／異抗壞血酸0.2/0.05、0.4/0.1、0.6/0.2、0.8/0.3及1.2/0.4 mg/g時，抗壞血酸之回收率為95.13-100.25%，異抗壞血酸為95.15-99.37%。變異係數皆小於10%。本檢驗方法之檢出限量維生素B1及B2皆為0.6ppm，抗壞血酸及異抗壞血酸均為30ppm。本調查於民國81 年11月至82年4月間於全省抽驗市售嬰兒奶粉檢體16件，穀類檢體8件及嬰兒營養食品檢體6件，共計30件。依本實驗建立之方法檢測結果，發現除了1件未檢出標示之三種維生素外，其餘含量均較標示量為高。維生素B1及B2部份，除了1件未檢出及5件超過衛生署規定之容許範圍（標示量之80-250%）與規定不符外，其餘皆在容許範國之內，維生素C則除了1件未檢出外，其餘皆在容許範圍之內。就三種維生素之部份數據與AOAC法比較時，統計數據顯示兩種方法所得結果無明顯差異。

High performance liquid chromatographic (HPLC) methods for the determination of thiamine, riboflavin and ascorbic acid in baby foods have been developed. To determine thiamine and riboflavin, the sample was mixed with 0.1N hydrochloric acid, and then digested withα-amylase. Thiamine was oxidized into thiochrome by adding 1% potassium ferricyanide in 15% sodium hydroxide, and neutralized with phosphoric acid. Finally, thiamine (as thiochrome) and riboflavin were simultaneously determined by the fluprimetric HPLC. Vitamin C was extracted with metaphosphoric acid -acetic acid solution, the solution was sonicated and filtered, then determined by UV-HPLC. Recovery studies of thiamine and riboflavin were performed at 2, 4, 6, 9 and 12 ppm fortification levels in rice flour samples. Average recoveries were 90.83-92.83% for thiamine and 96.00-99.25% for riboflavin. Recovery studies of ascorbic acid/erythorbic acid were performed at 0.2/0.05, 0.4/0.1, 0.6/0.2, 0.8/0.3 and 1.2/0.4 mg/g fortification levels in rice flour samples. Average recoveries were 95.13-100.25% for ascorbic acid and 95.15-99.37% for erythorbic acid. Coefficients of variation were less than 10%. The limits of detection for thiamine, riboflavin, ascorbic acid and erythorbic acid were 0.6, 0.6, 30 and 30 ppm, respectively. A total of thirty samples of infant formula, nee flour, wheat flour and ready-to-feed purchased from various markets in Taiwan were investigated, Results showed that contents of the three vitamins in most samples were higher than the amounts indicated on the labels, except sample No. 19 was not detected and other five samples exceeded leagal ranges (80-250% of label amounts). Statistical data showed no significant differences between HPLC method and AOAC method of determination for thiamine, riboflavin and ascorbic acid.