Thin metal films in resistivity-based chemical sensing

0395852 - ÚIACH 2014 HU eng A - Abstract
Podešva, Pavel - Foret, František
Thin metal films in resistivity-based chemical sensing.
CECE 2013. Program and Abstract Book. University of Pécs, 2013 - (Kilár, F.; Nagy, L.; Kiss, I.). s. 87-87. ISBN 978-963-642-517-3.
[CECE 2013. International Interdisciplinary Meeting on Bioanalysis /10./. 25.04.2013-27.04.2013, Pécs]
R&D Projects: GA ČR(CZ) GBP206/12/G014; GA MŠMT(CZ) EE2.3.20.0182
Institutional support: RVO:68081715
Keywords : chemiresistor * thin metal films * sensor
Subject RIV: CB - Analytical Chemistry, Separation

The chemiresistor is the sensor, which changes its resistivity with change of adjacent chemical environment [1,2]. In this case it is the gold thin film sensor [3] interacting with thiols in liquid phase. When thiolated molecule adsorb on the gold surface and building self-assembled monolayer [4,5], there is established the covalent bond between the sulphur and gold atom with 50% of C-C bond strength [6]. Covalently bonded gold atoms do not participate on electric conduction anymore, thus gaining the resistivity of the layer. When the gold layer is sufficiently thin (<80nm), this effect become evident and the difference between clear and completely saturated surface can be represented by shift in resistance up to 5%. The device self was constructed as a microfluidic apparatus with four sensing elements arranged in the Wheatstone bridge to exclude influence of the temperature coefficient of resistivity. In ideal case, when the bridge is balanced, the voltage between the sensing nodes is zero. Only one element was used at a time. Sample was fed into the channels by quartz capillaries. The chip consists of two parts – glass plate with sensors and PDMS part with channels bonded together with aid of plasma activation. We tested dynamic range of the device by aliquote series of thiolated and non-thiolated compounds. The thiolated compounds were chosen the glutathione and cysteine, the non-thiolated were used tripeptide Gly-Pro-Glu and β-alanine because of their similarity to their thiolated counterparts.
Permanent Link: http://hdl.handle.net/11104/0223744