Rapid analysis of guanidino compounds in serum from nephritic patients using column-switching with isocratic elution

The rapid method for baseline separation of ten guanidino compounds in serum from nephritic patients was designed using a single eluent with a column switching system. A porous graphitic carbon column and an octadecyl-bonded silica gel columns were used, (50 mm x 4.6 mm i.d.). Separation was completed within 15 min. The stable baseline permitted highly sensitive detection with excellent reproducibility. The system was applied to analyze guanidino compounds in sera from 175 nephritic patients. The hemodialysis process could not completely eliminate guanidino compounds, and the degree of removal varied between patients. The correlation among metabolites indicated the differences in disease.