Simultaneous determination of plasma catecholamine metabolites (homovanillic acid, 3,4-dihydroxy phenyl acetic acid, 3-methoxy-4-hydroxy-phenylglycol) using liquid chromatography with amperometric detection

Determination of three Tumor Biomarkers (Homovanillic Acid, Vanillylmandelic Acid, and 5‐Hydroxyindole‐3‐Acetic Acid) Using Flow Injection Analysis with Amperometric Detection

“…Many HPLC‐AD methods were used for the determination of only one of these biomarkers. For the sake of illustration, HVA was determined in different matrices, e. g. in urine (self‐fabricated wall‐jet/thin‐layer amperometric detector, glassy carbon working electrode, +0.7 V), in rat brain tissue (home‐made thin‐layer amperometric detector with a glassy carbon working electrode, +0.8 V), or in plasma (wall‐jet amperometric detector (Antec Leyden BV, The Netherlands), glassy carbon electrode, +0.8 V), with LOD s around 1 nmol ⋅ L −1 ; VMA was determined in urine after an ethyl acetate extraction (glassy carbon electrode cell TL‐8A (Bioanalytical Systems Inc., USA), +1.3 V). 5‐HIAA was monitored using an electrochemical detector LC‐3 with a glassy carbon electrode (Bioanalytical Systems Inc., USA) at +0.6 V, with LOD 0.5 μmol ⋅ L −1 , an electrochemical detector with a glassy carbon electrode cell LC‐4B (Bioanalytical Systems Inc., USA) at +0.55 V, with LOD 6.28 μmol ⋅ L −1 , and a glassy carbon electrode cell TL‐8A (Bioanalytical Systems Inc., USA) at +1 V, with estimated LOD 5.23 μmol ⋅ L −1 .…”