Water-soluble diboronic acid-based fluorescent sensors recognizing d-sorbitol

Herein, several boronic acid-based sensors were reported selectively recognizing d-sorbitol in aqueous solution. The fluorescence of sensor 15c was enhanced by 1.5-fold when combined with a low concentration of d-sorbitol (8.88 mu M), and the fluorescence enhanced by 0.6-fold after binding to d-fructose, while it did not change obviously when combined with other carbohydrates, including d-arabinose, d-galactose, d-mannose, d-ribose, d-maltose, d-xylose, d-glucose and d-glucosamine. Fluorescence tests were carried out in DMSO/PBS (pH 9, 0.1 M) solution (1 : 99, v/v), at room temperature, which indicated that the sensors are water-soluble. In addition, competition studies showed that sensor 15c works well as a d-sorbitol-specific fluorescence sensor in both the absence and presence of carbohydrate interferents. And sensor 15c has a high binding constant (10 922 +/- 776 M-1) and a low limit of detection (6.91 x 10(-7) M) at pH 9 among the investigated sensors toward d-sorbitol. Furthermore, sensor 15c was applied to the analysis of real samples (d-sorbitol for oral administration). These studies indicated that sensor 15c may serve as a potential tool to detect the content of d-sorbitol in drugs and food products.