The separation and analysis of symmetric and asymmetric dimethylarginine and other hydrophilic isobaric compounds using aqueous normal phase chromatography.

Two biologically important compounds with clinical relevance, asymmetric dimethylarginine and symmetric dimethylarginine, are analyzed using aqueous normal phase chromatography on silica hydride-based columns. Two different stationary phases were tested, a commercially available Diamond Hydride™ and a 2-acrylamido-2-methylpropane sulfonic acid experimental column. Two types of analytical protocols were investigated: analysis of the compounds when separation was achieved and analysis of the compounds with partial chromatographic separation. Urine samples from tuberculosis patients were tested for levels of asymmetric and symmetric dimethylarginine. The mass spectrometric technique of in-source fragmentation that can provide data similar to a tandem mass analyzer was evaluated as a means of identification and quantitation of the two compounds when complete separation is not achieved. This same protocol was also evaluated for two other isobaric compounds, glucose-1 and glucose-6 phohsphate, and leucine and isoleucine.