Quantificação de triptofano em plasma por cromatografia líquida de alta eficiência eco-friendly

Abstract

Trytophan is an essential amino acid and a serotonin (5-HT) synthesis precursor. Altered plasma levels of 5-HT are related to humor and behavioral alterations, anxiety, depression, sleep, fatigue and appetite suppression. In this study, a simple, fast, sensitive and specific high-performance liquid chromatography (HPLC) method was developed for determination of tryptophan with diode array detection (DAD) setting at programmed wavelength (λ = 267 nm). The separation was carried out on an analytical column ACE 5 C18 (150 mm x 4.6 mm internal diameter, 5 μm particle size) in less than 10 min. Mobile phase consisted of 5 mM sodium acetate and acetonitrile (92:8, v/v), isocratically eluted (1 mL min-1). Sample preparation consisted of plasma deproteinization with 8% perchloric acid solution. Tryptophan was characterized by a retention time of 5 min. Specificity was monitored using lipemic and hemolysate plasma samples and any peak was observed at the same retention time of tryptophan. A linear range was detected from 0.5 to 30.0 µg mL-1 and coefficients of variation calculated from intra and inter-day from 3 concentration (2.5; 5.0 e 15.0 µg mL-1) assays precision were 0.26 – 1.30% and 3.07 – 3.97% respectively. Satisfactory accuracy and recovery were obtained by this method, and use small amounts of organic solvent, characterizing the technique as an efficient and eco-friendly.