Direct determination of polyglucose metabolites in plasma using anion-exchange chromatography with pulsed...

High-performance anion-exchange chromatography with pulsed amperometric detection (HPAE-PAD) was evaluated for the quantitation of polyglucose metabolites (DP2-DP7) in human plasma. The method was investigated for accuracy, precision, specificity, linearity, range and analyte stability. Samples were prepared by dilution into the standard range (0.1-10 microg/ml) followed by deproteinization using a 30,000 molecular mass cut-off filtration device. The limit of detection was 0.05 microg/ml for all metabolites. Method precision for DP2-DP7 varied from approximately 2% R.S.D. in the upper range to approximately 15% R.S.D. at the limit of quantitation. Samples were stable following one or two freeze-thaw cycles and, after preparation, they could be refrigerated for up to 72 h. Application of this method to clinical plasma samples from continuous ambulatory peritoneal dialysis (CAPD) patients administered one daily night-time intraperitoneal exchange of 2 l of 7.5% polyglucose solution for four weeks indicated that plasma levels of DP2, DP3 and DP4 increased from baseline levels of <0.01 g/l to steady-state levels of 1.2+/-0.3, 1.2+/-0.3 and 0.4+/-0.1 g/l (mean+/-S.D.), respectively. These steady state plasma levels for DP2 and DP3 are comparable to previously reported levels in patients administered daily overnight 7.5% polyglucose dialysis solution.