Abstract
Tumour biomarker, 5-hydroxyindole-3-acetic acid, has been determined in human urine using HPLC with electrochemical (at a glassy carbon electrode in a "wall-jet" arrangement) and spectrophotometric detection (ED/UV) with solid phase extraction (SPE). Mobile phase was acetate-phosphate buffer at pH 2.5, gradient elution (increasing content of acetonitrile from 5 to 25% in 10 minutes) was used, flow rate of mobile phase was set up to 1 ml.minMINUS SIGN 1, detection potential to +1.1 V and detection wavelength of 279 nm.
Injected volume was 20 μl. Dependence of the peak current on the analyte concentration was linear in the whole tested concentration range (from 10 to 150 μmol.l-1) and obtained limits of detection (LODs) for HPLC-ED were 0.85 μmol.l-1 (calculated from peak height) and 0.72 μmol.l-1 (calculated from peak area).
For HPLC-UV, LODs were 3.30 μmol.l-1 (calculated from peak height) and 2.25 μmol.l-1 (calculated from peak area).