食品中溴酸鉀檢驗方法之探討及其含量之調查   全文下載

Studies on Analytical Methods for Determination of Potassium Bromate in Foods

本研究利用高效液相層析法（High performance liquid chromatography, HPLC）分析麵包及麵粉中溴酸鉀（potassium bromate）含量。檢體以去離子水溶解萃取，經LiChrolut SAX處理匣（過氯酸型）以0.06 M過氯酸鈉溶液（pH 3.5） 沖提，再以HPLC分析、定量。溴酸鉀以Zorbax SAX分離管，用0.06 M過氯酸鈉溶液（pH 3.5）移動相及於後置反應裝置中經80°C加熱衍生化，於紫外光波長355 nm分析。添加溴酸鉀0.2、0.5及1μg／mL於檢體中，其回收率分別為麵包80.0～83.1%，麵粉80.0～86.1%，變異係數在1.9%以下，最低檢出量為0.1 ppm。另以高效離子層析法（high performance ion chromatography, HPIC）針對麵粉做分析方法之探討，檢體前處理同於HPLC方法，但以OnGuard-Ag處理匣代替LiChrolut SAX處理匣去除氯離子後，以Dionex HPIC AS11分離管及Dionex HPIC AG 11保護管，經0.25 mM NaOH流洗液以流速0.8 ml／min進行分析，添加1、2及5μg／ml於檢體中，其回收率為79.7～86.3%，變異係數在3.9%以下，最低撿出量為0.5 ppm。比較兩種方法，以HPLC方法較佳。市售麵包40件及麵粉10件以HPLC法檢測，結果均未檢出。"

A high performance liquid chromatographic (HPLC) method for the determination of bromate in bread and flour has been developed. Bromate was extracted from samples with water. The extract was cleaned by the use of a LiChrolut SAX cartridge (perchlorate form) with 0.06 M sodium perchlorate solution (pH 3 .5) as a fluent. Bromate was separated with Zorbax SAX column by using 0.06 M sodium perchlorate solution (pH 3.5) the mobile phase, and detected at 355 nm after derivatization in the post column 80°C. Recovery studies were performed using bread and flour samples each fortified with bromate at 0.2, 0.5 and 1 µg/ml separately. Recoveries were in the range of 80.0-86.1% with coefficients of variation under 1.9%. The limit of detection was 0.1 ppm. For purposes of comparison, a study on high performance ion chromatography for the determination of bromate in flour was performed. Sample solution was prepared in the same way as in HPLC method, except that the sample was passed through an OnGuard-Ag cartridge instead of a LiChrolut SAX cartridge to remove chloride. Bromate was analyzed with Dionex HPIC AS 11 and AG 11 column by using 0.25 mM sodium hydroxide solution as an eluent, in combination with a conductivity detector. Recovery studies were performed using flour samples fortified with bromate at 1, 2 and 5 µg/ml. Recoveries were in the range of 79.7-86.3% with coefficients of variation under 3.9%. The limit of detection was 0.5 ppm. Forty bread and ten flour samples collected from various markets were analyzed. No bromate residue was detected in any samples tested.