title: Nano-molar deltamethrin sensor based on electrical impedance of PAH/PAZO layer-by-layer sensing films.
abstract: This work reports a novel deltamethrin (DM) sensor able to detect nano-molar concentrations in ethanol solutions. The sensing layer consists of a thin film, obtained via a layer-by-layer technique, from alternate adsorption of poly(allylamine chloride) (PAH) and poly[1-[4-(3-carboxy-4-hydroxyphenylazo)-benzenesulfonamide)-1,2-ethanediyl]sodium salt] (PAZO) onto a solid support with interdigitaded gold electrodes. The sensor response, obtained from impedance spectroscopy measurements, was revealed to be linear with respect to the real part of impedance, taken at 100 Hz, when plotted as a function of the logarithm of deltamethrin molar concentrations in the micro- to nano-molar range. Sensor sensitivity was of 41.1 ± 0.7 kΩ per decade of concentration for an immersion time above 2 min and the reproducibility is approximately 2% in a binary solution of ethanol and deltamethrin. The main insight of this work concerns to DM detection limits as the sensor revealed to be able to detect concentrations below 0.1 nM, a value which is significantly lower than any reported in the literature and close what is appropriate for in situ environmental contaminant detection.
authors: CEFITEC, Departamento de Física, Faculdade de Ciências e Tecnologia, FCT, Universidade Nova de Lisboa, Caparica 2829-516, Portugal. lma@campus.fct.unl.pt
authors: Luís Miguel Gomes
authors: LM
authors: Abegão
authors: Jorge Humberto Fernandes
authors: JH
authors: Ribeiro
authors: Paulo António
authors: PA
authors: Ribeiro
authors: Maria
authors: M
authors: Raposo
mesh_terms: D000499:Allylamine / Q000737:chemistry*; D003217:Conductometry / Q000295:instrumentation*; D004566:Electrodes; D004573:Electrolytes / Q000737:chemistry; D004784:Environmental Monitoring / Q000295:instrumentation*; D004785:Environmental Pollutants / Q000032:analysis; D004867:Equipment Design; D019544:Equipment Failure Analysis; D007306:Insecticides / Q000032:analysis; D008567:Membranes, Artificial; D008832:Microchemistry / Q000295:instrumentation; D053758:Nanoparticles / Q000032:analysis*; D009570:Nitriles / Q000032:analysis*; D011137:Polystyrenes / Q000737:chemistry*; D011722:Pyrethrins / Q000032:analysis*; D014159:Transducers
chemical_list: D004573:Electrolytes; D004785:Environmental Pollutants; D007306:Insecticides; D008567:Membranes, Artificial; D009570:Nitriles; D011137:Polystyrenes; D011722:Pyrethrins; C523575:poly(1-(4-(3-carboxy-4 hydroxyphenylazo)benzene sulfonamido)-1,2-ethanediyl, sodium salt); C017180:decamethrin; D000499:Allylamine
references: Interdiscip Toxicol. 2009 Mar;2(1):1-12
references: 21217838
references: Bull Environ Contam Toxicol. 2003 Feb;70(2):296-9
references: 12545362
references: Biosens Bioelectron. 2003 Oct 1;18(11):1365-9
references: 12896837
references: Langmuir. 2013 Jan 8;29(1):448-55
references: 23215445
references: Spectrochim Acta A Mol Biomol Spectrosc. 2011 Sep;79(5):1704-9
references: 21684806
references: J Nanosci Nanotechnol. 2007 Aug;7(8):2659-66
references: 17685281
references: Anal Chem. 2003 Feb 15;75(4):953-5
references: 12622390
references: Ecotoxicol Environ Saf. 1997 Dec;38(3):195-9
references: 9469868