Surface assembly of nano-metal organic framework on amine functionalized indium tin oxide substrate for impedimetric sensing of parathion

The present paper reports the assembly and pesticide sensing application of a nanometal organic framework [Cd(atc)(H2O)(2)](n) ('atc'=2-aminoterephthalic acid). The assembly of the NMOF film has been achieved by sequential dipping of a 2-aminobenzylamine (2-ABA) modified indium tin oxide (ITO) slide in organic linker 'atc' and metal ion 'Cd2+' solutions. The different structural and morphological characteristics of the NMOF thin film have been characterized. The availability of pendent -COOH functional groups on the assembled NMOF film is exploited to synthesize a pesticide immunosensor by conjugating the NMOF film with anti-parathion antibody. This immunosensor has been explored for the electrochemical impedance spectroscopy (EIS) based analysis of parathion in the concentration range of 0.1-20 ng/mL. The proposed detection is specific with respect to other organophosphate compounds, e.g. malathion, paraoxon, fenitrothion, monochrotophos and dichlorovos. The proposed sensor shows the detection limit of 0.1 ng/mL and it is applicable for analysis of parathion in a rice sample. The sensor's performance is validated by computing the obtained results with gas chromatographic data. (C) 2014 Elsevier B.V. All rights reserved.