Nutritional Folate Deficiency in the United Kingdom

An amperometric microbial biosensor for the determination of vitamin B12

“…For this reason, amongst strict vegetarians, there can be a nutritional imbalance, bad absorption symptoms, and other gastrointestinal problems 4, 6-7 . The daily requirements of vitamin B 12 are very low when compared to other vitamins: from 1 to 2 µg, however, regardless of this a small drop in these levels is considered a deficiency [7][8][9][10] .…”

“…4,6,7 The daily requirements of vitamin B 12 are very low when compared to other vitamins: from 1 to 2 mg, however, regardless of this a small drop in these levels is considered a deciency. [7][8][9][10] For decades, different instrumental methods have been developed for the determination of vitamin B 12 , generally based on the detection of cobalt(II), the ones studied the most and with the best sensitivity are the ones with chemiluminescence [11][12][13][14][15][16][17] where detection limits have been obtained up to 3.6 Â 10 À14 M. 16 Likewise, methods have been reported using atomic absorption spectroscopy (AAS), 18,19 uorometric methods, [20][21][22][23][24] high performance liquid chromatography (HPCL), radioisotopic methods, 25-28 microbiological, [28][29][30] and electrochemical methods. [31][32][33] However, the applicability of these methods for the measurement of vitamin B 12 in real samples is somewhat limited, because these methods are not able to distinguish between unbound cobalt, and cobalt associated with vitamin B 12 , that is without taking into consideration that these conventional methods are costly, time consuming, reactive, and in some occasions dangerous to health because of the use of highly carcinogenic reagents.…”