Porous beads are provided of a polymer of a non-acidic monomer and a cross-linker having polar functionality, one of which is hydrophilic, the other of which is hydrophobic, further comprising residues of polyvinyl alcohol. The beads may be molecularly imprinted or non-molecularly imprinted. The use of such beads in the removal of nitroso-containing compounds from material containing them is also disclosed. Also disclosed is a non-molecularly imprinted polymer which is selectively adsorbent for at least one tobacco specific nitrosamine in the presence of nicotine, said polymer being a polymerization product of a non-acidic monomer and a cross-linker having polar functionality, one of which is hydrophilic, the other of which is hydrophobic.