NANOLITER TITRATION BASED ON PIEZOELECTRIC DROP-ON-DEMAND TECHNOLOGY AND LASER-INDUCED FLUORESCENCE DETECTION

An automated technique for fast acid-base titration of 9-nL sample vol umes has been developed, based on the use of piezoelectrically driven pipets and laser-induced waveguide fluorescence detection. As an examp le, a standard titration of a H2SO4 solution with NaOH was examined by utilizing fluorescein as an: indicator. The technique had reproducibi lity in quantitative determination on the order of 1%. The technique a llows hundreds of individually executed unattended titrations to be pe rformed in a few hours on an area less than 3 cm(2). The lowest amount of acid titrated was similar to 670 fmol.