title: Detection of haemoglobin using an adsorption approach at a liquid-liquid microinterface array.
abstract: The behaviour of haemoglobin (Hb) at the interface between two immiscible electrolyte solutions (ITIES) has been examined for analytical purposes. When Hb is fully protonated under acidic conditions (pH <pI) in the aqueous phase, it undergoes a potential-dependent adsorption and complexation, at the interface, with the anions of the organic phase electrolyte. When utilised as a simple and fast preconcentration step, consisting of adsorbing the protein at the interface, in conjunction with voltammetric desorption, this opens up the ITIES to the adsorptive stripping voltammetry approach. Utilising a 60 s adsorption step and linear sweep voltammetry, a linear response to Hb concentration in aqueous solution over the range 0.01-0.5 μM was achieved. The equation of the best-fit straight line was I(p) = 7.46 C - 0.109, R = 0.996, where I(p) is the peak current (in nanoampere) and C is haemoglobin concentration (in micromolar). The calculated detection limit (3σ) was 48 nM for a 60 s preconcentration period, while the relative standard deviation was 13.3% for six successive measurements at 0.1 μM Hb. These results illustrate the prospects for simple, portable and rapid label-free detection of biomacromolecules offered by electrochemistry at arrays of liquid-liquid microinterfaces.
authors.affiliation: Nanochemistry Research Institute, Department of Chemistry, Curtin University, GPO Box U1987, Perth, WA 6845, Australia.
authors.forename: Eva
authors.initials: E
authors.lastname: Alvarez de Eulate
authors.forename: Lauren
authors.initials: L
authors.lastname: Serls
authors.forename: Damien W M
authors.initials: DW
authors.lastname: Arrigan
mesh_terms: D000327:Adsorption; D000818:Animals; D002417:Cattle; D055664:Electrochemical Techniques / Q000379:methods*; D004573:Electrolytes / Q000737:chemistry*; D006454:Hemoglobins / Q000032:analysis*; D057230:Limit of Detection
chemical_list: D004573:Electrolytes; D006454:Hemoglobins