Coliform bacteria immobilized on titanium dioxide nanoparticles as a biosorbent for trace lead preconcentration followed by atomic absorption spectrometric determination

Coliform bacteria physically immobilized on titanium dioxide nanoparticles can be used as a biosorbent for solid phase extraction of lead (II) ions from aqueous solution using a flow injection system coupled to flame atomic absorption spectrometry (FAAS). Effects of pH value, sample volume, flow rates of loading and elution, and the type and volume of eluent were investigated. Lead ions were sorbed on a biosorbent mini-column at pH 6.0, eluted with 1 mol L-1 HCl and then determined by FAAS. The limit of detection for the water samples is in order of 0.90 mu g L-1. The accuracy of the method was confirmed by analyzing a certified reference material (GBW 07605; tea). The results are in good agreement with the certified value. The precision of the method was also satisfactory. The procedure was applied to the evaluation of lead ions in river water, wine, and baby food.