Benchmarking the placement of hydrosulfide in the Hofmeister series using a bambus[6]uril-based ChemFET sensor.

Hydrosulfide (HS) is the conjugate base of gasotransmitter hydrogen sulfide (HS) and is a physiologically-relevant small molecule of great interest in the anion sensing community. However, selective sensing and molecular recognition of HS in water remains difficult because, in addition to the diffuse charge and high solvation energy of anions, HS is highly nucleophilic and readily oxidizes into other reactive sulfur species. Moreover, the direct placement of HS in the Hofmeister series remains unclear.

Hydrosulfide-selective ChemFETs for aqueous HS/HS measurement.

We have prepared and characterized hydrosulfide-selective ChemFET devices based on a nitrile butadiene rubber membrane containing tetraoctylammonium nitrate as a chemical recognition element that is applied to commercially available field-effect transistors. The sensors have fast (120 s) reversible responses, selectivity over other biologically relevant thiol-containing species, detection limits of 8 mM, and a detection range from approximately 5 to 500 mM. Sensitivities are shown to be 53 mV per decade at pH 8.