Preconcentration of α-amino acids by 1-vinyl-3,5-dimethylpyrazole and ethylene dimethacrylate copolymers

Abstract

The goal of present work is establishing sorption concentrating characteristics of essential α-amino
acids tryptophan and histidine by new copolymers based on 1-vinyl-3,5-dimethylpyrazole (VDMP) with
ethylene dimethacrylate (EDMA). Cross-linked copolymers of VDMP and EDMA with different degree of
cross-linking are synthesized by free radical copolymerization in chloroform and methanol. It’s found that
sorption characteristics of both amino acids are higher for copolymers obtaining in chloroform, and the best
sorption characteristics are achieved for copolymers with VDMP:EDMA=1:15 molar ratio in static sorption
with spectrophometric determination. VDMP:EDMA=1:15 copolymer synthesized in chloroform also demonstrates
the highest values of distribution coefficient in case of dynamic sorption. Researching of pH effect
shows that sorption efficiency is maximal in acid media. Amino acid desorption by water is not quantitative,
but 0.1 M NaOH using allows reaching quantitative desorption. Based on carried out researching the
technique of sorption-spectrophotometric determination of histidine and tryptophan in aqueous solutions is
proposed. To sum up new copolymers based on VDMP and EDMA are effective sorbents for histidine and
tryptophan from aqueous media in static and dynamic sorption