The stability of retinol, alpha-tocopherol, trans-lycopene, and trans-beta-carotene in liquid-frozen and lyophilized serum.
The concentrations of retinol, alpha-tocopherol, and trans-beta-carotene in lyophilized serum stored at -25 degrees C and -80 degrees C have been monitored for 10 years. There was no evidence of degradation of any of these compounds over the 10-year period. Retinol, alpha-tocopherol, and trans-beta-carotene were less stable at -25 degrees C in liquid-frozen serum than they were in lyophilized serum. At -80 degrees C, trans-beta-carotene levels were stable for up to 3 years of storage in liquid-frozen serum. Both retinol and alpha-tocopherol appeared stable in liquid-frozen serum for at least 5 years at -80 degrees C. The effect of repeated freeze/thaw cycles on retinol, alpha-tocopherol, trans-lycopene, and trans-beta-carotene in liquid-frozen and reconstituted lyophilized serum both stored at -20 degrees C was also studied. Retinol, alpha-tocopherol, trans-lycopene, and trans-beta-carotene in reconstituted lyophilized serum stored at -20 degrees C were stable for at least 3 days with minimal (< 5) freeze/thaw cycles.
Brown Thomas
J
J
Analytical Chemistry Division, National Institute of Standards and Technology, Gaithersburg, MD 20899, USA. jeanice.brownthomas@nist.gov
Duewer
D L
DL
Kline
M C
MC
Sharpless
K E
KE
D016588:Anticarcinogenic Agents / Q000097:blood*; D000975:Antioxidants / Q000032:analysis*; D001771:Blood Banks; D001800:Blood Specimen Collection / Q000379:methods; D002338:Carotenoids / Q000097:blood*; D004355:Drug Stability; D005612:Freeze Drying; D005615:Freezing; D006801:Humans; D000077276:Lycopene; D013997:Time Factors; D014801:Vitamin A / Q000097:blood*; D014810:Vitamin E / Q000097:blood*; D019207:beta Carotene / Q000097:blood*
D016588:Anticarcinogenic Agents; D000975:Antioxidants; D019207:beta Carotene; D014801:Vitamin A; D014810:Vitamin E; D002338:Carotenoids; D000077276:Lycopene