Photo-induced chemiluminescent method for determination of reducing sugars

In the present study, a simple and sensitive photo-induced chemiluminescence (CL) method for the quantitation of reducing sugars, including fructose, glucose, sucrose and lactose, was developed. This method was based on the on-line photocatalytic reaction of the reducing sugars, using a home-made photoreactor consisting of PTEF tube helically coiling around a high-pressure mercury UV lamp. Reducing sugars were detected by direct CL emission resulting from the reaction between the photoproducts and luminol. To maximize the signal intensity, the effects of irradiation time, flow rate, luminol concentration, buffer pH and concentration were tested. Under optimum conditions, the linear dynamic ranges were all 0.36-18 mg/L and the relative standard deviations (RSDs) were 1.8-2.3%, with limits of detection (3sigma) of 0.06 mg/L for fructose, glucose, sucrose and lactose. Finally, interference effects from ascorbic acid, amino acids (alanine, glycine, serine, leucine and methionine) and some metal ions and anions were also investigated.