Fast-scan controlled-adsorption voltammetry for the quantification of absolute concentrations and adsorption dynamics

Area of Science:

• Electrochemistry
• Analytical Chemistry
• Biophysics

Background:

• Fast-scan cyclic voltammetry (FSCV) traditionally requires background subtraction for neurotransmitter quantification.
• This reliance limits accurate measurement of absolute concentrations.
• Previous methods were constrained by flow injection techniques for concentration changes.

Purpose of the Study:

• To develop and characterize a novel voltammetric technique for direct, absolute concentration measurements.
• To enable the study of diffusion-controlled adsorption dynamics of biogenic amines.
• To overcome limitations of traditional FSCV in determining absolute analyte levels.

Main Methods:

• Development and characterization of fast-scan controlled-adsorption voltammetry (FSCAV).
• Utilized an implicit finite-difference model for mass-transport-limited adsorption.
• Experimental validation of the FSCAV technique in vitro.

Main Results:

• FSCAV enables direct in vitro measurements of absolute concentrations without flow injection.
• Achieved a sensitivity of 81 ± 11 nA/μM for dopamine.
• Established a limit of detection of 3.7 ± 0.5 nM for dopamine.
• Model simulations agreed with experimental findings for adsorption dynamics.

Conclusions:

• FSCAV is a significant advancement for determining absolute concentrations of adsorbing species.
• The technique facilitates the study of mass-transport-limited adsorption dynamics.
• FSCAV combines novel instrumentation with validated simulations for robust measurements.