http://www.creative-diagnostics.com/Vitamin-B12-ELISA-Kit-3808-464.htm

Vitamin B12as a trace element belongs to the biologically
important chelateformers. The basic unit consists of a corrin ring with cobalt as a centralatom. Cobalt is sixfold coordinated by four nitrogen atoms, one cyanide and adimethylbenzimidazol group. Vitamin B12 forms a stable complex,which is absorbed in the lower part of the small intestine, with theso-called intrinsic factor present in the gastric juice. A lack of vitamin B12can lead among other things to pernicious anemia. This disease is notgenerated by an insufficient supply of vitamin B12, but by theabsence of intrinsic factor. A pernicious anemia can be treated by a highdosage of vitamin B12. The existing detection procedures aremainly microbiological methods, but also HPLC and thin-layer chromatography,all of which are associated with a high amount of time and instrumentation.With the present test kit it is possible, to determine vitamin B12quantitatively in vitaminated food in a significantly faster way (2.5 to 4hours inclusive sample pretreatment) compared with a conventionalmicrobiological assay (24 to 48 hours).