The use of poly(dimethylsiloxane) surface modification with gold nanoparticles for the microchip electrophoresis

Abstract: Poly(dimethylsiloxane) (PDMS) microfluidic channels modified by citrate-stabilized gold nanoparticles after coating a layer of linear polyethylenimine (LPEI) were successfully used to separate dopamine and epinephrine, which were difficult to be separated from baseline in native and hybrid PDMS microchannels. In-channel amperometric detection with a single carbon fibre cylindrical electrode was employed. Experimental parameters of separation and detection processes were optimized in detail. The analytes were well separated within 100s in a 3.7cm long separation channel at a separation voltage of +800V using a 30mM phosphate buffer solution (PBS, pH 7.0). Linear responses of them were obtained both from 25 to 600μM with detection limits of 2μM for dopamine and 5μM for epinephrine, respectively. The modified PDMS channels have a long-term stability and an excellent reproducibility within 2 weeks. [Copyright &y& Elsevier]