Amino acids
Alanine, Cystine, Glycine
Sendaway - Biochemistry
Monthly
The sulphur containing amino acids (cystine, homocystine) are stable if frozen at -70oC.
NTC
http://testguide.adhb.govt.nz/EGuide/?elv=1&name=Plasma%20aminoacids&pn=1961&mn=987&sd=3&ts=14c9c458857
AMINP