Dear Sir. Concerning your issue about the procedure for extracting tryptophan amino acid from spirulina. Tryptophan is one of 8 essential amino acids that our bodies need. The body uses tryptophan to produce serotonin, which can then used to make melatonin, our “sleep hormone.” Individual free amino acids were extracted and quantified according to the method of Park et al. (2014) with modifications. Briefly, a 100 mg portion of a fine powdered sample was mixed with 1.2 mL of 5% trichloroacetic acid (TCA) in a 2 mL Eppendorf tube and vigorously shaken for 5 min. The slurry sample was incubated at room temperature for 60 min, and the upper layer was then separated by centrifugation. The collected samples were diluted with 0.1 M HCl and then filtered through a 0.45 μm PTFE syringe filter. The filtrate was then analysed by HPLC (Agilent Technologies, Palo Alto, CA). The HPLC analyses of free amino acids were conducted according to the “rapid, accurate, sensitive, and reproducible HPLC analysis of amino acids analysis” method with Zorbax Eclipse-AAA columns using an Agilent 1100 HPLC system. Briefly, the separation of the free amino acids was performed on a Zorbax Eclipse AAA analytical column. The oven temperature of the column was set at 40°C, and the detection wavelength was set a 338 nm. The injection volume was 10 μL. The mobile phase consisted of a mixture of 40 mM NaH2PO4 (pH 7.8, solvent A), and solvent B (ACN, MeOH, and water at a 45 : 45 : 10 v/v/v ratio) was passed at a rate of 2.0 mL/min. The HPLC separation parameters were as follows: 0 min, 0% B; 0–1.9 min, 0% B; 1.9–21.1 min, 57% B; 21.1–21.6 min, 100% B; 21.6–25 min, 100% B; 25–25.1 min, 0% B; and 25.1–30 min, 0% B. A sample with an amino acid content of 50 pmoL/μL was used as the standard. The quantifications of the different amino acids were based on the peak areas and were calculated as equivalents of the standard compounds. All contents are expressed as milligrams ∗ gram/fresh weight (FW). I think the following below links may help you in your analysis:

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4737012/

https://plenteousveg.com/tryptophan-foods/

Thanks

Thank you Dr Isam Eldin Hussien Elgailani.

It is a good direction for me.

Dear

Please see the method of Park et al. (2014)

Goodluck

Dear Qassim Kshash

Thanks for your suggestion

Tryptophan is destroy by acid extraction and use alkaline (NaOH) hydrolysis for Tryptophan:

Steps

Dried sample obout 50 mg suspended in 20 ml of 3N-NaOH sealing under Ar or N2 gas hydrolyse for 17 hr at 110 0C or 3 hr at 160 0C centrifugation for 10 min at 16,000g take then supernatant dilute with 50 folds with water

Then directly inject (20ul) for amino acid analysis

Agree with@Isam Eldin Hussein Elgailani

Wish you good luck