Based On Three Substances Quenching The Ru(bpy)₃²⁺-tpra Electrochemiluminescence

The recent development in the fields of electrochemiluminescence (ECL) and quenching of the electrochemiluminescence were reviewed. Analytical workers always concerned about the ECL of Ru(bpy)₃²⁺-TPrA system, especially for quenching. We proposed several new quenching substances based on previous reports about quenching electrochemiluminescence. In this dissertation, the study was focused on the quenching of the electrochemiluminescence of Ru(bpy)₃²⁺-TprA. The dissertation is composed of four chapters as followings: In the introduction (chapter I), the introduction of ECL development, characteristics, classifications, mechanics and its application in analytical view is reviewed.Chapter II, a new ECL method for the detection of diphenylamine-4-sulfonate and its derivatives is described. Efficient quenching ECL of the Ru(bpy)₃²⁺ -TPrA system by a novel quencher, diphenylamine-4-sulfonate, has been investigated. The quenching behaviors can be observed with a 100-fold excess of over Ru(bpy)₃²⁺. The mechanism of quenching is believed to involve energy transfer from the excited-state Ru(bpy)₃²⁺* to the dimer of diphenylamine-4-sulfonate, which was formed after the electrochemical oxidation of diphenylamine-4-sulfonate at the electrode surface. Photoluminescence experiments coupled with bulk electrolysis support formation of the diphenylamine-4-sulfonate dimer upon electrochemical oxidation.Chapter III, efficient quenching electrochemiluminescence (ECL) of the Ru(bpy)₃²⁺-tripropylamine (TPrA) system by a novel quencher Caffic acid (CA) has been investigated. The quenching behaviors can be observed with a 100-fold excess of CA over Ru(bpy)₃²⁺. The mechanism of quenching is believed to involve energy transfer from the excited-state Ru(bpy)₃²⁺* to the electro-chemical oxidation of CA, which was formed at the electrode surface.Chapter IV , quenching electrochemiluminescence (ECL) of the Ru(bpy)₃²⁺ -TPrA system by a novel quencher, tyrosine(TYR), has been investigated. The quenching behaviors can be observed with a 100-fold excess of TYR over Ru(bpy)₃²⁺. The mechanism of quenching is believed to involve energy transfer from the excited-state Ru(bpy)₃²⁺* to the oxidation of TYR, which was formed after the electrochemical oxidation of TYR at the electrode surface. It has been proposed that the interaction of phenol with Ru(bpy)₃²⁺ leads toπ-stacking interactions of the aromatic rings, as well as hydrogen bonding between the hydroxyl group on phenol and water.The presence of hydroxyl groups in the 1,2-positions in catechol may result in unfavorable overlap and subsequent quenching.Based on the above discuss, compared these types of substances quenching efficiency on Ru(bpy)₃²⁺-TprA electrochemiluminescence (ECL). According to the literature, These types of substances in different positions of the aromatic rings led to different quenching efficiency. p-benzoquinone quenching efficiency is relatively bigger than o- benzoquinone. Because the presence of groups in the 1,2-positions in catechol may result in unfavorable overlap and subsequent quenching.Quench excited states of transition-metal complexes via energy transfer.