TLC Separation and Analysis of Vitamin B₁₂and Related Compounds in Food

To evaluate why differences between the vitamin B12 contents determined by both microbiological and intrinsic factor-chemi-luminescence B12 assay methods occur in some edible shellfish and algal foods, or how much loss of B12 occurs in food during microwave heating, some B12-compounds and their degradation products formed during microwave heating were purified and characterized using silica gel 60 thin layer chromatography. Although dried green and purple lavers (nori), some algal health foods, and most shellfish contained considerable amounts of true B12, pseudovitamin B12, an inactive B12-compound, predominated in spirulina tablets. Significant loss of B12 occurred in foods during microwave heating due to the conversion of B12 to inactive B12 degradation products. These results indicate that thin-layer chromatography has great advantages (simplicity, flexibility, speed, and relative inexpensiveness) for the separation and analysis of B12 compounds in foods.