Determination of sorbitol in erythrocytes of diabetic and healthy subjects by capillary gas chromatography

A gas-liquid chromatographic method, using a fused silica capillary column, for the determination of red cell sorbitol is described. The capillary column gives complete resolution of the polyols xylitol, inositol, mannitol, sorbitol and galactitol, even when the glucose peak in the red cell chromatogram is dominating. The identity of sorbitol, and its single elution from the capillary column has been confirmed by mass spectrometry. Recovery of sorbitol from various red cell samples was 101% +/- 3.2 (mean +/- SD, n = 7). Precision, estimated from duplicate diabetic red cell sorbitol analyses was CVdup = 3.5% (n = 18) and from run to run analyses CVinterassay = 4.0% (n = 6). Sorbitol levels determined in erythrocytes of 19 healthy subjects were 5.9 +/- 1.6 nmol/ml red cells and in erythrocytes of 18 insulin-dependent diabetics 17.8 +/- 8.2 nmol/ml red cells (means +/- SD). The method described offers a reliable and specific tool to study in vivo polyol pathway activity in relation to some diabetes-associated complications.