Optimization of the selectivity of pyrene immunoaffinity columns prepared by the sol-gel method

The sol-gel method opened a new path for synthesizing immunoaffinity column packing materials by encapsulating antibodies in the pores of a silica glass matrix. This paper describes different strategies for the optimization of the selectivity of pyrene immunoaffinity columns synthesized by encapsulating the immunoglobulin (IgG) fraction of an anti-pyrene antiserum in a porous silica glass. The selectivity of the columns which are designed for the determination of pyrene in aqueous samples is limited by the retention of cross-reacting and nonspecifically adsorbed polycyclic aromatic hydrocarbons (PAHs). An optimum in selectivity is achieved by a new method to wash the columns with a mixture of a high molecular weight polymer which blocks nonspecific adsorption sites and a surfactant which removes unwanted substances by inclusion into micelles. Optimal results were achieved by washing with 5% (v/v) Roti-Block in 10:90 acetonitrile-water (v/v). Roti-Block is the trade name for a mixture of a high molecular weight poly(vinylpyrrolidone) with a nonionic surfactant dissolved in PBS buffer.