X-Message-Number: 11995 Date: Wed, 23 Jun 1999 13:04:11 -0700 (PDT) From: Doug Skrecky <> Subject: lyophilization is critical for refrigerated storage Authors Brown Thomas J. Duewer DL. Kline MC. Sharpless KE. Institution Analytical Chemistry Division, National Institute of Standards and Technology, Gaithersburg, MD 20899, USA. Title The stability of retinol, alpha-tocopherol, trans-lycopene, and trans-beta-carotene in liquid-frozen and lyophilized serum. Source Clinica Chimica Acta. 276(1):75-87, 1998 Aug 10. Abstract 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. Rate This Message: http://www.cryonet.org/cgi-bin/rate.cgi?msg=11995