Determination of 1,5-anhydroglucitol in urine by high performance liquid chromatography and an enzyme sensor

A simple high performance liquid chromatographic method combined with an enzyme sensor has been developed to measure 1,5-anhydroglucitol in urine. The enzyme sensor consists of a hydrogen peroxide electrode and a chitosan membrane of an immobilized pyranose oxidase. As the system does not resist interfering substances, urine samples are first purified by passing them through a two-layer column packed with (1) strongly basic anion (OH- form, the upper layer) and (2) strongly acidic cation (H+ form, the lower layer) exchange resins. 1,5-Anhydroglucitol is efficiently recovered in the flow-through fraction of the column. In this system, the minimum detectable concentration of 1,5-anhydroglucitol is 0.1 mg/L, and the measurable range extends from 0.1 to 60 mg/L. The coefficient of variation values of the within-day and day-to-day precisions are 3.0-6.5% and and 4.4-6.7% respectively, and there is good agreement between the results measured by our method and those obtained by the gas-liquid chromatographic/mass spectrometric method (r = 0.994). The method we have described here has been successfully used to elucidate a mechanism for the reducing 1,5-anhydroglucitol level in the serum and plasma of patients.