Reversible detection of proteases and their inhibitors by a pulsed chronopotentiometric polyion-sensitive electrode

Polymer membrane electrodes operated by pulsed chronopotentiometry have recently been introduced to replace traditional ion-selective electrodes for a number of applications. While ion-selective electrodes for the polycation protamine have been reported, for instance, a pulsed chronopotentiometric readout mode (called here pulstrode) provides improved stability and reproducibility while exhibiting sufficient selectivity for the direct detection of protamine in undiluted whole blood samples. Here, such protamine-sensitive pulstrodes are applied for the real-time detection of the activity of the protease trypsin and its soybean inhibitor. This is possible because small fragments produced by the trypsin digestion are not detectable by the protamine-sensing membrane. The real-time response to the proteolytic reaction is shown to exhibit good reproducibility and reversibility, and the initial reaction rate is dependent on the concentration of the protease and its inhibitor

Selectivity Enhancement for Chloride Ion by In(III)‐Porphyrin‐Based Polymeric Membrane Electrode Operated in Pulsed Chronopotentiometric Mode

A robust selectivity enhancement of an In(III)‐porphyrin ionophore‐based chloride‐selective electrode under pulsed chronopotentiometric measurement mode that enables the detection of chloride ions in the presence of a normally interfering concentration of salicylate ions is described. This enhancement is achieved by the rapid depletion of the surface concentration of the more dilute lipophilic anion during an initial anodic current pulse period due to extraction of this preferred anion into the membrane phase. Measurement of chloride with a detection limit of 8 mM and near Nernstian response slope in the presence of 1 mM salicylate is possible using the pulstrode method.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/90345/1/643_ftp.pd

Polyion‐Sensitive Polymeric Membrane‐Based Pulstrode as a Potentiometric Detector in Liquid Chromatography

Potentiometric polyion‐sensitive polymeric membrane electrodes are capable of detecting a wide variety of polyionic macromolecules. Herein, we utilize this lack of selectivity to report the first application of this sensor technology as a detector in liquid chromatography (LC). A reversible polycation pulstrode based on tridodecylmethylammonium‐dinonylnaphthalene sulfonate doped within a polymeric membrane is employed as the LC detector. Poly‐arginines/protamine mixtures are separated by cation‐exchange/affinity chromatography on an immobilized heparin column, with eluted polycation peptide bands clearly observed via the pulstrode detector. The LC‐pulstrode system is further applied to follow the production of different polycation peptides derived from thermolysin catalyzed protamine digestion.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/113143/1/1823_ftp.pd

Properties and customization of sensor materials for biomedical applications.

Low-power chemo- and biosensing devices capable of monitoring clinically important parameters in real time represent a great challenge in the analytical field as the issue of sensor calibration pertaining to keeping the response within an accurate calibration domain is particularly significant (1–4). Diagnostics, personal health, and related costs will also benefit from the introduction of sensors technology (5–7). In addition, with the introduction of Registration, Evaluation, Authorization, and Restriction of Chemical Substances (REACH) regulation, unraveling the cause–effect relationships in epidemiology studies will be of outmost importance to help establish reliable environmental policies aimed at protecting the health of individuals and communities (8–10). For instance, the effect of low concentration of toxic elements is seldom investigated as physicians do not have means to access the data (11)