Supramolecular Host-Guest Chemistry in Design of Ionophores for Potentiometric Chemfet Sensors
Datum
2022-10-26
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University of Oregon
Zusammenfassung
Potentiometric sensors are a viable technology for monitoring aqueous anion concentration in real-time, a key process in numerous applications. However, selectivity in ???? ??????? ??????? ??????????? ?? ???? ??? ?? ??????? ????????? ?????????? ??????? solution-state binding, and potentiometric calibrations is needed to tune ionophore design and optimize sensor performance.The work reported in this dissertation explores the use of host-guest chemistry by incorporating synthetically tailored receptors into polymer membrane-coated insulated gate field effect transistors. Potentiometric calibrations and interference studies yield data about reusability, sensitivity, detection limit, and selectivity. In the case of barbituric acid, devices were prepared based on membranes containing Hamilton-type receptors as the ionophore. They exhibit near Nernstian sensitivity and demonstrate utility of Hamilton receptors within polymer membranes for potentiometric detection of barbiturates in water. This work also investigates the effects of receptor preorganization on sensor performance and compares these effects to those observed for similar receptor systems in solution.
Using a similar approach, this work also investigates sensor materials for iv
hydrosulfide. We prepared and evaluated devices based on a nitrile butadiene rubber without ionophore, only containing lipophilic salt as a chemical recognition element applied to an insulated gate field-effect transistor surface. The sensors have quick and reversible responses and selectivity over some thiol-containing species.
To improve HS- sensor performance, we synthesized a novel bambusuril macrocycle to employ as the membrane ionophore. This yielded detection limits below 0.5 mM and selectivity over chloride and cysteine. Continuing to study the utility of bambusuril macrocycles as ionophores, we begin an investigation with the Hofmeister series suing bambus[6]uril-doped membranes. Thus far, we find that in the absence of ionophore, bromide disrupts the expected response with a lower detection limit than iodide and perchlorate. When a bambus[6]uril macrocycle is incorporated as the ionophore, detection limits dropped at least one order of magnitude for all anions tested with the exception of bromide. To further elucidate a trend imparted by the ionophore, further experiments should be performed across the spectrum of the Hofmeister series.
This dissertation includes both co-authored unpublished material and previously published work.