Determination of sorbitol and galactitol at the nanogram level in biological samples by high-performance liquid chromatography.

Aldose reductase is an enzyme that plays an important role in diabetic complications such as cataract and neuropathy. The best way to estimate the enzymatic activity of this enzyme in vivo consists of measuring the accumulation of sorbitol or galactitol in various types of cells or tissues. A sensitive method to measure the polyols in biological samples by high-performance liquid chromatography has been developed. This method is based on the fact that polyols like sorbitol and galactitol react with phenylisocyanate to yield uv-absorbing derivatives at 240 nm. Applications to the separation and determination of polyols in biological samples of various origins, such as lenses, sciatic nerves, human skin fibroblasts, and red cells, are described and illustrated.