To Identify Amino Acid Enantiomers Of Electrochemical Luminescence

An Electrochemiluminescence (ECL) method has been developed for the discrimination of chiral molecules. It is a new method for discrimination of chiral molecules, depending on the principle and technology of electrochemistry, photochemistry and stereochemistry. The amino acid enantiomers can be directly determined by the method without performing enantioseparation. In this work, the electrochemiluminescent discrimination of amino acid enantiomers has been investigated and discussed in the three aspects.1. ECL discrimination of amino acid enantiomers has been investigated using ECL reagent tris(2,2'-bipyridine)ruthenium(II) (Ru(bpy)32+) in the solution. ECL response to L-amino acids is stronger than D-amino acids. According to difference of ECL intensity, applied potential were set respectively at 850mV, 880mV and 930mV for proline, phenylalanine and tyrosine. The luminous intensity varies linearly with a change in the L or D composition of amino acids at the applied potential. On the basis of a formula inferred from the luminous intensity, the synthetic samples of proline were determined as a feasible test to application of the method, the relative errors of the result are less than or equal to 6%. The enantioselectivity of the enantiomers to Ru(bpy)a2+ was demonstrated by chronocoulometry.2. ECL discrimination of amino acid enantiomers has been investigated using a Pt electrode coated with chitosan encapsulated Ru(bpy)32+/silica gel membrane. ECL responds more intensely to D-amino acids than to L-amino acid. Applied potential were set respectively at 850mV and 880mV for proline and phenylalanine. The luminous intensity varies linearly with a change in the D or L composition of amino acids at the applied potential. A similar feasible test to application of the method has been performed and given the relative errors of less than 3%. The enantioselectivity of chitosan membrane to the enantiomers of amino acid was demonstrated by chronocoulometry.3. ECL discrimination of amino acid enantiomers has been investigated using a chiral probe, which prepared by chitosan encapsulated Ru(bpy)32+/silica gel membrane on a Ptielectrode to link covalently D or L pentose. D chiral probe responds more intensely to L-amino acids than to D-amino acid; L chiral probe responds more intensely to D-amino acids than to L-amino acid. This discrimination capacity of ECL chiral probes for amino acid enantiomers has been also discussed.