Determination of Tryptophan in Raw Materials, Rat Brain and Human Plasma by RP-HPLC Technique

This paper describes tryptophan (TRP) estimation in raw human plasma and rat brain by reversed-phase high-performance liquid chromatography (RP-HPLC). Estimation was carried out on a Purospher STAR C18 column using water–acetonitrile (90:10 v/v, at pH 2.7) mixture at a rate of 1.5 mL/min as mobile phase. Eluents were monitored at 273 nm by an ultraviolet detector. The method was linear (R 2 > 0.999), precise (intra-day and inter-day precision <2%) in the range of 0.25–20 mg/mL. The detection and quantification limits were 0.0144 mg/mL and 0.0437 mg/mL, respectively. In human plasma, Day 1 and Day 2 precision were 0.054–2.29% and 1.66– 3.7%; whereas precisions in rat brain were 1.23 –2.3% and 0.677–4.2%, respectively. The method was applied to study TRP level in human smokers and in arthritic rat brain. An efficient RPHPLC method was developed for TRP determination that worked for clinical and research purposes.