Rapid and simple determination of inulin in biological fluids by high-performance liquid chromatography with light-scattering detection

We report a new high-performance liquid chromatography method developed for measuring inulin in plasma and urine using ion moderated partition chromat ography and evaporative light-scattering detection. Samples are deproteiniz ed with a zinc acetate and phosphotungstic acid solution and added with mel ezitose as an internal standard. The chromatographic separation is carried out in 16 min at a flow-rate of 0.6 ml/min using deionized water as the mob ile phase. Within-run precision, measured at four different concentrations (0.050 mg/ml, 0.150 mg/ml, 0.300 mg/ml and 1.200 mg/ml), ranges from 1.7 to 3.4% in plasma and from 1.5 to 3.5% in urine. Similarly, between-run preci sion is in plasma from 2.0 to 4.3% and in urine from 2.0 to 4.4%. Analytica l recovery ranges from 97.9 to 100.1% in plasma and from 99.1 to 99.7% in u rine, respectively. Detection limit (signal-to-noise ratio=3) is 5 mu g/ml both in plasma and urine. The method is simple, sensitive, without interfer ence due to hexoses or drugs commonly taken by patients with renal diseases , and offers the advantage of measuring inulin without previous hydrolysis of the molecule. (C) 2000 Elsevier Science B.V. All rights reserved.