Ultra-trace electrochemical impedance determination of bovine serum albumin by a two dimensional silica network citrate-capped gold nanoparticles modified gold electrode

In this work, a gold electrode (GE) was modified by coating with two dimensional silica network/citrate capped gold nanoparticles–poly(diallyldimethylammonium chloride) (GE–TDSN–CGNP–PDDA) for ultra-sensitive determination of Bovine Serum Albumin (BSA). After covalently binding of a silica network (in two-dimensional form) on the surface of a gold electrode, via twice in situ hydrolysis of 3-mercaptopropyl-tri-ethoxysilane, citrate capped gold nanoparticles (CGNP) were chemically adsorbed on the silica cage. Subsequently, PDDA was bonded to CGNP via electrostatic interaction of positively charged polymer and negatively charged stabilizer of CGNP. Analytical properties of GE–TDSN–CGNP–PDDA were studied by Electrochemical Impedance Spectroscopy (EIS). The detection limit for measured BSA was found to be 8.4×10−13molL−1 and the measuring linear concentration range of the proposed sensor was 9.9×10−12–1.6×10−10molL−1 of BSA. In addition, GE–TDSN–CGNP–PDDA exhibited good stability with high selectivity and was applied for determination of BSA in some samples with satisfactory results. [Display omitted] •A novel sensor with good stability and high sensitivity.•Ultra-trace determination of Bovine Serum Albumin, 8.4×10−13M.•Use of intrinsic sensitive electrochemical impedance spectroscopy sensor.•A gold electrode with silica network/citrate capped gold nanoparticles.