Enzyme-linked immunosorbent assay for detection of organophosphorylated butyrylcholinesterase: a biomarker of exposure to organophosphate agents

Lowering of the detection limit of solid-state lead-selective electrodes was achieved by using the tuned galvanostatic polarization method. A Nernstian response was obtained down to nanomolar concentrations (low detection limit 10(-9) mol dm(-3)Pb(2+)). Good repeatability of the calibration curves was achieved by using a well established measuring procedure. Relatively high cathodic current densities were applied to the solid-state membrane in order to shorten the measurement time. Successful determination of lead in a synthetic sample (pPb(2+)=7.97±0.08) was achieved by introducing an analytical protocol and favourably compared to inductively coupled plasma mass spectrometry (pPb=7.93). By applying this method, a significant improvement in the detection limit of solid-state lead-selective electrodes was attained.