Voltammetric sensor based on the copper (II) amino acid complex for the determination of tryptophan enantiomers

A voltammetric sensor based on a composite of polyarylene phthalide and graphitized carbon black Carboblack C modified with chelate complexes L-argenato-L-alaninate copper (II) has been developed for the recognition selective determination tryptophan enantiomers. The conditions modifying are optimized, effective surface area (A = 4.38 ± 0.06 mm2) resistance (Ret 1.29 0.08 kΩ) calculated. optimal recording voltammograms enantiomers selected: range operating potentials is 0.5-1.2 V, potential sweep rate 20 mV/s, holding time electrode in test solution 5 s. electrochemical analytical characteristics were studied when registering differential pulse It shown that dependence signal concentration linear from 1.25·10-6 to 1·10-3 M detection limits 0.90·10-6 L-Trp 0.66·10-6 D-Trp. shows greatest sensitivity successfully tested determine content L- D-Trp enantiomer solutions presence excipients part medicines biologically active additives. proposed allows human urine blood plasma. To evaluate capabilities sensor, "entered-found" method was used. When determining model solutions, relative standard deviation does not exceed 2.3 %, error 1.7 %. D- biological fluids, ranges 0.3-1.7 0.3-5.6 research results show there no significant systematic error.