مشخصات پژوهش

In this research, a simple method was developed for the separation and determination of l-tryptophan in aqueous solutions. The method consists of a solid-phase extraction (SPE) cleanup system utilizing a column packed with nickel–aluminum layered double hydroxide as a nanosorbent, followed by a spectrofluorometric detection step. Some factors influencing the SPE efficiency, including pH, the sample flow rate, the elution conditions and the amount of nano-sorbent were evaluated and optimized. The selectivity of the presented SPE method with regard to l-tryptophan was studied in the presence of other amino acids and potentially interfering ions. Under optimum conditions, the calibration graph was linear in the range of 0.1– 120.0 ìg L.1 with a correlation coefficient of 0.9975. The limit of detection and relative standard deviation for l-tryptophan were 0.01 ìg L.1 and 0.62 %, respectively. The maximum sorption capacity of the sorbent for l-tryptophan was 37.6 mg g.1. The method was successfully applied to determine l-tryptophan in several food samples with recoveries in the range of 96.2–104.2 % for the spiked samples.