SOLUBLE HIGHLY COLORED PHENYLBORONIC ACIDS AND THEIR USE IN GLYCOHEMOGLOBIN QUANTIFICATION

Water soluble dye-phenylboronic acid conjugates (dye-PBAs) possessing strong absorption of visible light are introduced as new reagents for the determination of glycohemoglobin. Their functionality and prospect ive use are demonstrated in a semi-homogenous glycohemoglobin assay. T he assay is based on cis-diol esterification of dye-PEA to glycohemogl obin followed by selective precipitation of hemoglobin from solution, co-precipitating bound dye-PEA. Quantification of the molar ''dye-PBA/ Hb''-ratio in redissolved precipitates using either absorption or fluo rescence spectroscopy, reflects the glycation level of the blood sampl es used. Future development of the assay principle is illustrated in a filter based assay, collecting the precipitated hemoglobin on a filte r followed by reflectometric readings directly on the precipitate. The significance of this work ties first, in the demonstration of a new p rinciple for the determination of glycohemoglobin, and second, as an i llustration of the prospective use of water soluble, signal-forming no n-immobilised boronic acids in the determination of cis-diol containin g analytes. (C) 1997 Elsevier Science B.V.