Supercritical CO2 (ScCO2) has been used to prepare molecularly imprinted polymers of poly(styrene-co-maleic acid) (PSMA) for targeted uracil (URA). The condition of ScCO2 was on 16 MPa between 35 and 50 degrees C. The resultant imprinted membranes prepared at 35 and 50 degrees C bound URA with 9.2 +/- 0.10 and 12.6 +/- 0.06 pmol g(-1), respectively. Competitive binding studies were undertaken in binary substrate solution containing each of .URA/DMURA, URA/Thymine, and URA/Cytosine with 2 W. The URA imprinted membrane showed high separation factor (at) with 17 for both URA/DMURA and URA/Thymine and for URA/Cytosine, alpha = 13. Results strongly suggested that the URA imprinted membrane had effective selectivity hydrogen bonding to separately bind in the binary components to the template. Effect of organic solvents on the URA imprinting in ScC02 was also studied, in addition to comparison of properties with those obtained in both ScC02 and water. Evidence presented that ScC02 medium was effective to prepare the URA imprinted membrane. We discussed that ScC02 fluid was efficient to fix the shape of URA template into the PSMA membrane through hydrogen bonding. (c) 2008 Wiley Periodicals, Inc.