Weigh 0.1-0.2 g of your amino acid into a small Erlenmeyer flask, and slowly add about 0.5 mL of concentrated HCl using a Pasteur pipe. Swirl the mixture until the amino acid dissolves (if you have tryptophan or methionine, see below), then add 1-2 mL of saturated NaCl solution, swirl the flask to mix, stopper the flask, and place it in an ice bath. Let the mixture stand in ice for at least 1 hour, then suction filter to isolate the solid product. Suction the product for at least 1 hour to dry it. Weigh the product and calculate % yield.
If your amino acid is glycine or tryptophan, the HCl adduct will precipitate when concentrated HCl is added. Add 1-2 mL of acetone (for glycine) or water (for tryptophan) and swirl to allow the reaction to finish. Let stand in an ice bath for 15 minutes, then suction filter to isolate the product. Suction the product for at least 1 hour to thoroughly dry it, then weigh the product and calculate % yield.
If your amino acid is methionine, isolation of the HCl adduct is challenging. Consult with the instructor for some ideas!