Enantioselective Voltammetric Sensors Based on Amino Acid Complexes of Cu(II), Co(III), and Zn(II)

• Published in: Journal of analytical chemistry (New York, N.Y.) N.Y.), 2021-12, Vol.76 (12), p.1438-1448
• Main Authors: Zil’berg, R. A., Zagitova, L. R., Vakulin, I. V., Yarkaeva, Yu. A., Teres, Yu. B., Berestova, T. V.
• Format: Article
• Language: English
• Subjects: Amino acids; Analytical Chemistry; Chemistry; Chemistry and Materials Science; Coordination compounds; Copper; Enantiomers; Glassy carbon; Sensors; Statistical methods; Systematic errors; Tryptophan; Zinc
• ISSN: 1061-9348; 1608-3199
• DOI: 10.1134/S1061934821120145

The electrochemical and analytical characteristics of enantioselective sensors based on glassy carbon electrodes modified by chelate complexes (bis(L-phenylalaninate) copper(II), glycinato-L-phenylalaninate copper(II), tris(L-phenylalaninate) cobalt(II), bis(L-phenylalaninate) zinc) are studied. It is found that the most promising sensor for determining tryptophan enantiomers is the sensor modified by copper(II) (bis)L-phenylalaninate. In determining tryptophan enantiomers, this sensor provides a linear concentration range from 6.25 × 10 –7 to 0.5 × 10 –3 M for L-tryptophan and from 5 × 10 –6 to 0.5 × 10 –3 M for D-tryptophan. The sensor is more sensitive to L-tryptophan. The proposed sensor was used for the recognition and determination of tryptophan enantiomers in human urine and plasma samples, and also in a mixture of enantiomers. The statistical assessment of the results of determinations by the spiked–found method indicates the absence of a significant systematic error.