Tryptophan Click to View Image C11H12N2O2 204.23
L-Tryptophan [73-22-3]. »Tryptophan contains not less than 98.5percent and not more than 101.5percent of C11H12N2O2,as L-tryptophan,calculated on the dried basis. Packaging and storage— Preserve in well-closed containers. USP Reference standards á11ñ USPl-Tryptophan RS. Identification,Infrared Absorption á197Kñ. Specific rotation á781Sñ: between -29.4and -32.8. Test solution: 10mg per mL,in water (heat gently to dissolve,if necessary). pHá791ñ: between 5.5and 7.0,in a solution (1in 100). Loss on drying á731ñ Dry it at 105for 3hours:it loses not more than 0.3%of its weight. Residue on ignition á281ñ: not more than 0.1%. Chloride á221ñ A0.73-g portion shows no more chloride than corresponds to 0.50mLof 0.020Nhydrochloric acid (0.05%). Sulfate á221ñ A0.33-g portion shows no more sulfate than corresponds to 0.10mLof 0.020Nsulfuric acid (0.03%). Iron á241ñ: 0.003%. Heavy metals,Method IIá231ñ: 0.0015%. Organic volatile impurities,Method IVá467ñ: meets the requirements. Assay— Transfer about 200mg of Tryptophan,accurately weighed,to a 125-mLflask,dissolve in a mixture of 3mLof formic acid and 50mLof glacial acetic acid,and titrate with 0.1Nperchloric acid VS,determining the endpoint potentiometrically.Perform a blank determination,and make any necessary correction.Each mLof 0.1Nperchloric acid is equivalent to 20.42mg of C11H12N2O2. Auxiliary Information— Staff Liaison:Lawrence Evans,III,Ph.D.,Scientist Expert Committee:(DSN)Dietary Supplements:Non-Botanicals USP28–NF23Page 1999 Phone Number:1-301-816-8389