Abstract: Silica gel was used as a carrier for preparing an immunoaffinity column (IAC) to determine chloramphenicol. Amino groups were introduced to the surface of silica gel using 3-aminopropyltriethoxysilane (APTES) as a silane coupling agent and the modified silica gel was conjugated with anti-chloramphenicol antibodies using glutaraldehyde. As a result, a conjugation ratio of 72% was obtained. The maximum adsorption capacity of the prepared IAC was 80 ng/mL. The elution solvent was PBS containing 70% methanol. After sample pretreatment by three different methods, chloramphenicol residues in milk were purified and enriched using the IAC and determined by ELISA

Key words: immunoaffinity column, silica gel, anti-chloramphenicol antibody, glutaraldehyde