Electrochemical detection biotin

The biggest challenge in the HPLC analysis of biotin is its detection. Biotin does not exhibit UV absorbance or fluorescence, nor is it electrochemically active (180). Refractometry, a notoriously nonspecific technique, is the only means for direct detection of biotin. Fortunately, biotin can be converted to UV absorbing or fluorescent derivatives. 

K. Kamata, T. Hagiwara, M. Takahashi, S. Uehara, K. Nakayama, and K. Akiyama, Determination of biotin in multivitamin pharmaceutical preparations by HPLC with electrochemical detection, J. Chromatogr., 356 326 (1986). 

Ultrasensitive Electrochemical Detection of Biotin using an Electrically Addressable Site-oriented Antibody Immobilization Approach... 

Reprinted from Biosensors <6 Bioelectronics, 26, Ho, J. A. et ai, Ultrasensitive electrochemical detection of biotin using electrically addressable site-oriented antibody immobilization approach via aminophenyl boronic acid, 1021-7, Cop5right (2010), with permission from Elsevier.)... 

Wright, J.D., Rawson, K.M., Ho, W.O., Athey, D., and McNeil, C.J., 1995. Specific binding assay for biotin based on enzyme channelling with direct electron transfer electrochemical detection using horseradish peroxidase. Biosensors and Bioelectronics. 10 495-500. 

Electrochemical detection of biotin after separation by HPLC has also been described (108). A C18 reversed-phase column was used, with acetonitrile-0.05 M potassium phosphate buffer pH 2.0 (15 85 v/v) as eluent, to separate different vitamins. The detection limit for biotin was 10 ng. 

Biotin does not exhibit UV absorbance. It neither shows fluorescence nor electrochemical activity. Therefore, it needs to be derivatized. 4-Bromomethylmethoxiycoumarin (BMMC) [590], 9-anthryldiazomethane (ADAM) [591], and 1-pyrenyldiazomethane (PDAM) [592] have been used as precolumn reagents to convert biotin to fluorescent absorbing derivatives. Instead, to obtain derivatives that are UV detectable, hydrazines are used, such as 2-nitrophenylhydrazine hydrochloride... 

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