Study of aqueous humour by 1H NMR spectroscopy

The aim of this work was to study the composition of the samples of human aqueous humour including the protein content. Using H-1 NMR spectroscopy many compounds (proteins, glucose, lactate, citrate and other metabolites) can be identified and their concentrations evaluated using the internal standard. While the concentrations of non-proteins in aqueous humour were relatively stable, the amount of proteins differed much more. In most of the spectra, the signals of proteins were hardly distinguishable from the baseline. For some samples a significantly higher protein content (more than 1 mg/ml) was found. The total protein concentration expressed in albumin equivalents can be determined by comparing the spectra measured by S2PUL (standard measurement) and CPMG (protein suppression) pulse sequentions. For comparison, the spectra of rabbit and bovine aqueous humour are also given. (C) 1999 Elsevier Science B.V. All rights reserved.