The difference spectrophotometric assay of 5-hydroxymethylfurfuraldehyde in parenteral formulations of dextrose

A selective difference spectrophotometric assay for 5-hydroxymethylfurfuraldehyde (5-HMF) in injectable solutions of dextrose is described, which eliminates the interference that occurs in simple direct spectrophotometric procedures from other ultraviolet absorbing substances in the solution. The assay is based on the measurement of the absorbance of 5-HMF in an aliquot of the injection relative to that of an equimolar solution in which the 5-HMF has been reduced by sodium borohydride. The difference absorbance, which is due to the loss of absorption after reduction of 5-HMF, is proportional to the concentration of 5-HMF and is free from interference from the ingredients of the formulations and from other UV-absorbing decomposition products of dextrose.