HPLC chromatograms using mobile phase containing CTAB and OSA showing complete separation of: A, phthaloylglutamine and phthaloylisoglutamine authentic standards; B, separation of the peak 4 fraction from mice urine; and C, separation of the equivalent of p... HPLC chromatograms using mobile phase containing CTAB and OSA showing complete separation of: A, phthaloylglutamine and phthaloylisoglutamine authentic standards; B, separation of the peak 4 fraction from mice urine; and C, separation of the equivalent of peak 4 from patient urine into two peaks showing the presence of both phthaloylglutamine and phthaloylisoglutamine. Jun Lu et al. Clin Cancer Res 2003;9:1680-1688 ©2003 by American Association for Cancer Research