Effect of freezing on the concentration of drugs of abuse in urine.
Benzoylecgonine, 11-nor-delta 9-tetrahydrocannabinol-9-carboxylic acid (THC-acid), phencyclidine, codeine, morphine, amphetamine, methamphetamine, and lysergic acid diethylamide were dissolved in urine, stored frozen in plastic tubes at -16 to -18 degrees C, defrosted, transferred to other tubes, and analyzed by gas chromatography/mass spectrometry (GC/MS); no significant loss of compound was observed, except for THC-acid, which showed an average loss of 11%, ranging from 0 to 34% of the total concentration. The loss is attributed to the decrease in solubility of the compound and to adherence to the side of the container during freezing.
Paul
B D
BD
Navy Drug Screening Laboratory, Norfolk, VA 23511-2597.
McKinley
R M
RM
Walsh
J K
JK
Jamir
T S
TS
Past
M R
MR
D005615:Freezing; D006801:Humans; D013287:Illicit Drugs / Q000652:urine*; D015813:Substance Abuse Detection / Q000379:methods*
D013287:Illicit Drugs