Deterioration of Stored Inulin Solutions

Abstract

WHILE using a batch of inulin for determination of glomerular filtration rate in man, we found that some ampoules were giving much lower serum inulin-levels than were expected from the dose given. The inulin had been stored in the dark at 20°–25° C, in sealed ampoules, and from the batch number it was established that it had been manufactured thirteen years ago by Thomas Kerfoot and Co., Barnsley. We investigated the deterioration of inulin with time by determining the inulin content by the acid hydrolysis and resorcinol technique¹ in fifteen ampoules of the thirteen-year-old batch of inulin, in seven ampoules of inulin one year old and in inulin recrystallized from the one-year-old batch, after washing with distilled water at 20° C. The ages of the inulin batches were kindly provided by the manufacturers.