Phenol and p-cresol accumulated in uremic serum measured by HPLC with fluorescence detection

We developed a simple and sensitive high-performance liquid chromatographic (HPLC) method that uses fluorescence as a detector for quantifying serum phenol and p-cresol in uremic patients on hemodialysis. Identification of phenol and p-cresol was confirmed by liquid chromatography/mass spectrometry. Because the HPLC method requires only simple extraction by ethyl acetate and does not require further steps such as derivatization, it is simple and rapid compared with gas chromatography or gas chromatography/mass spectrometry. Concentrations of phenol and p-cresol in uremic serum were significantly (p < 0.01) higher than those in normal serum. Reduction rates of phenol and p-cresol by hemodialysis were lower than those of urea and creatinine, suggesting a protein-binding property of phenol and p-cresol. This method will be useful for monitoring serum phenols in dialyzed patients as an index of hemodialysis adequacy.