1 Electrodeposition of Silver Amalgam on Thin Gold Film Electrodes for Voltammetric Detection of 4-nitrophenol and DNA labeled by osmium tetroxide-bipyridine complex Pavlina Havranova a , Filip Ligmajer a,b,c , Ales Danhel a * a Institute of Biophysics of the Czech Academy of Sciences, Kralovopolska 135, CZ-61265 Brno, Czech Republic b Central European Institute of Technology, Brno University of Technology, Purkynova 123, CZ-612 00 Brno, Czech Republic c Institute of Physical Engineering, Brno University of Technology, Technicka 2, CZ-616 69 Brno, Czech Republic * e-mail: danhel@ibp.cz Abstract Alternative electrode materials suitable for preparation of novel working electrode architectures applicable in detection of biopolymers such as nucleic acids, proteins or glycoproteins, represent a significant contribution in bio-electroanalysis. Herein, electrodes made of vapor-deposited gold thin films (vAuE) were used as alternative substrate for the electrodeposition of silver amalgam particles (AgAPs), next to already used indium tin oxide and pyrolytic graphite. Conditions and parameters of double pulse chronoamperometry were optimized towards the most-sensitive voltammetric detection of 4-nitrophenol (4-NP). The resulting electrodes were characterized by scanning electron microscope with energy dispersive X-ray spectroscopy. While 4-NP could not be detected by bare nonactivated vAuEs at all, their electrochemical activation offered limit of detection (LoD) 25 and 5 µmol.l −1 by means of CV and DPV, respectively. Herein introduced AgAP electrodeposited on vAuE offered 2.5-times lower LoDs 10 µmol.l −1 by CV and comparable LoD 5 µmol.l −1 by DPV. Advantageously, AgAPs could be repeatedly deposited on and anodically dissolved from the vAuE with relative standard deviation 13% of ten-times repeated DPV signal of 4-NP (100 µmol.l −1 ). In coparison to vAuE, the vAuE-AgAP offered about 400 mV broader