FIELD: analytical chemistry.
SUBSTANCE: invention relates to analytical chemistry and specifically to a method of determining tryptophan in model aqueous solutions by cyclic voltammetry on a graphite electrode modified with colloidal silver particles. Method involves modification of graphite electrode with colloidal particles of silver from silver sol for 120 s at accumulation potential of -0.8 V with subsequent recording of cathode maxima at a rate of change of potentials of 100 mV/s on background of 0.1 M NaOH solution in the range of potentials from -0.6 to 1.5 V. Concentration of tryptophan is determined from the value of cathode maxima of current-voltage curves in the range of potentials from minus 0.2 to 0.0 V relative to the saturated silver chloride electrode by the method of addition of certified mixtures.
EFFECT: reduction of minimum detectable concentration 1⋅10-12 mol/l and expanded range of determined concentrations 1⋅10-12–1⋅10-10 mol/l, reduction of analysis time.
1 cl, 2 dwg, 1 tbl
