食品中規定外煤焦色素分離鑑別方法之探討

SEPARATION AND IDENTIFICATION OF ILLEGAL COAL TAR DYES IN FOOD

食品中規定外煤焦色素係指具有強毒性或致癌性，因安全顧慮、公告刪除者（如Amaranth）及與我國規定不符之輸入國法定煤焦色素（如AcidRed）。本研究針對八種規定內煤焦色素及Amaranth等十六種規定外煤焦色素，依據中國國家標準食品中著色劑之檢驗方法，將檢體中之色素抽出後，分別以濾紙層析法，薄層層析法及高效液相層析法等三種方法進行分析探討，結果均能獲得良好之分離效果。其分離條件分別為濾紙層析用濾紙為東洋濾紙No.50，理想展開溶媒為氨水：水（5:95）之溶液100ml中含檸檬酸鈉2g等四種。薄層層析部份，薄層板為矽膠，展開溶媒為丙酮：丁酮：氨水：水（60:140:1:60）等六種展開溶媒。至於高效液相層析之分析條件則為層析管：LichroCART RP-18，移動相：（a）酸性煤焦色素為0.005M Tetrabutyl Ammonium Phosphate與甲醇兩種溶媒採線性梯度遞變，（b）鹽基性煤焦色素為0.005M Pentane Sulphonic Acid與甲醇（15:85），紫外部檢出器：254nm。本計畫抽購70件檢體，包括國產食品52件，進口食品18件，經檢驗結果，使用規定外煤焦色素之檢體，國產食品8件，進口食品1件，共計9件，佔12.86%。檢出情形分別為Rhodamine B一件，OrangeII二件，Phloxine一件，Metanil Yellow一件，另外四件則檢出MetanilYellow及OrangeII兩種混合使用之規定外媒焦色素。其餘61件檢體均使用規定內煤焦色素，佔87.14%。三種分離鑑別方法中，薄層層析法之凝聚性及感度皆較濾紙層析法為佳，高效液相層析法除了確認鑑別外，又可利用其高感度檢驗色素濃度較低之檢體，同時尚可定量。

The methods of paper chromatography (PC), thin layer chromatography (TLC) and high performance liguid chromatography (HPLC) were studied to separate and identify 8 regulative 16 illegal coal tar dyes. The conditions of dye separation by PC, TLC and HPLC were as follow : (1) PC : Toyo filter paper No.50 and four developing systems. (2) TLC : Silica gel plate and six developing systems. (3) HPLC : column, Lichro CART RP-18, 5 11m, mobil phase systems : (a) 0.005M tetrabutyl ammonium phosphate and methanol with linear gradient for acid coal tar dyes. (b) 0.005M pentane sulfonic acid and methanol (85 : 15) for basic coal tar dyes, detector, 254nm. The HPLC method is superior than PC and TLC methods in term of speed and sensitivity. Using these three methods, the contents of dyes were effec tively inveotigated in 70 commercial food samples. The results showed that illegal coal dyes were detected in 9 samples (12.86%).