Electrochemical analysis of the alanine phenylthiohydantoin derivative by cathodic stripping voltammetry.
A square-wave cathodic stripping voltammetry method for alanine determination as its phenylthiohydantoin (PTH-alanine) derivative is developed. To this end, all the chemical and instrumental variables affecting the determination of PTH-alanine are optimized. From studies of the mechanisms governing the electrochemical response of PTH-alanine, it was concluded that it is an electrochemically irreversible system with a diffusive-adsorptive reduction phenomenon. Under optimal conditions, the variation of analytical signal (I(p)) with PTH-alanine concentration is linear in the 2.4x10(-8)-4.8x10(-7) M range, with a LOD of 1.2x10(-8) M and a LOQ of 4.2x10(-8) M, a RSD (%) less than 11%, and a E(r) (%) less than 10%. The optimized method was applied to the determination of PTH-alanine obtained from a synthetic protein after Edman reaction and the results were corroborated by high-performance liquid chromatography with UV detection.
Vilaseca
C
C
Departamento Química Analítica y Análisis Instrumental, Facultad de Ciencias, Universidad Autónoma de Madrid, Cantoblanco, 28049 Madrid, Spain.
Quintana
M C
MC
Vicente
J
J
Hernández
P
P
Hernández
L
L
D000409:Alanine / Q000737:chemistry*; D002851:Chromatography, High Pressure Liquid; D004563:Electrochemistry / Q000295:instrumentation / Q000379:methods*; D008956:Models, Chemical; D015394:Molecular Structure; D010669:Phenylthiohydantoin / Q000737:chemistry*; D013056:Spectrophotometry, Ultraviolet
D010669:Phenylthiohydantoin; D000409:Alanine