NEW ENHANCERS FOR THE CHEMILUMINESCENT PEROXIDASE-CATALYZED CHEMILUMINESCENT OXIDATION OF PYROGALLOL AND PURPUROGALLIN

The effects of various boronate compounds. 4-biphenylboronic acid, 4-b romobenzeneboronic acid, trans-4-(3-propionic acid)phenylboronic acid and 4-iodophenylboronic acid. on the horseradish peroxidase (HRP) cata lysed chemiluminescent oxidation of pyrogallol and purpurogallin by pe roxide were investigated. trans-4-(3-Propionic acid)phenylboronic acid produced a 13.7-fold enhancement in the peak light emission from the chemiluminescent HRP catalysed pyrogallol reaction (detection limit fo r HRP < 1.25 fmol). At low enhancer concentration a single peak of lig ht emission was observed and as the enhancer concentration increased t he time to peak light emission became progressively longer. The chemil uminescence showed two peaks at higher concentrations (>54.3 mu mol/L) and the individual peak times depended upon the concentration of the enhancer. All of the boronates enhanced peak light emission in the che miluminescent HRP catalysed purpurogallin reaction. 4-Biphenylboronic acid was the most effective and it enhanced peak light emission 314-fo ld. The practical detection limit for HRP (Type VIA) using this enhanc er was 4.18 pmol (peak emission at 20 minutes). This compound also enh anced peak light emission 232-fold from a chemiluminescent HRP-purpuro gallin reaction in which molecular oxygen replaced peroxide as the oxi dant.