The effect of pH on inhibition and enhancement of luminol–H2O2–CO2 chemiluminescence (CL) by 18 phenolic compounds and 20 amino acids was studied. It was found that most of the tested compounds showed an inhibiting effect at lower pH and an enhancing effect at higher pH. At a midrange pH, for some phenolic compounds with two ortho-position –OH, both an inhibiting and an enhancing peak were simultaneously observed. UV–visible spectra of the tested phenolic compounds at different pH values were studied. The mechanism for CL inhibition and enhancement was proposed. It is likely that the competition of the –OH or the –NH2 group and other reducing groups in the molecules with luminol for O2·− led to the CL inhibition. A reaction of –COO− and quinone or ketone formed by phenolic compounds at higher pH via deprotonation with O2·− also resulted in the CL enhancement.
You have requested a machine translation of selected content from our databases. This functionality is provided solely for your convenience and is in no way intended to replace human translation. Neither BioOne nor the owners and publishers of the content make, and they explicitly disclaim, any express or implied representations or warranties of any kind, including, without limitation, representations and warranties as to the functionality of the translation feature or the accuracy or completeness of the translations.
Translations are not retained in our system. Your use of this feature and the translations is subject to all use restrictions contained in the Terms and Conditions of Use of the BioOne website.
Vol. 79 • No. 3