Determination of Trace Cholinergic Compounds and the Evaluation of Their Relative Receptor Activity with the Use of a Receptor Biosensor and an Ion-Selective Choline Electrode

A comparative assessment of the analytical capabilities of a tensoresistive biosensor based on muscarinic acetylcholine receptors and a potentiometric choline sensor was performed. It was found that the receptor biosensor is promising for the determination of ultratrace amounts of cholinergic agents with a detection limit of 10^–7–10^–10 M. The selectivity of the potentiometric choline sensor is equal to the selectivity of the receptor biosensor; however, the sensitivity of the former is lower by two orders of magnitude. Nevertheless, it can be successfully used for evaluating the relative receptor activity of cholinergic agents.