Background: Nanoparticles have a promising potential in electrochemical sensitivity. Polyaniline
(PANI) received significant attention in the latest years owing to its high conductivity and excellent
electrochemical stability. This research aims to study the effect of gold nanoparticles capped
octadecyl amine (Au/ODA) on polyaniline emeraldine salt (ES) electrochemical sensitivity to formaldehyde
(FA) using DPV technique. Furthermore, ES and Au-ODA/ES have been applied for the first
time in sensing FA. Few relevant patents to the topic have been reviewed and cited in this article.
Methods: Emeraldine salt (ES) was prepared by doping the prepared emeraldine base (EB) powder with dodecylbenzene
sulfonic acid (DBSA) at a ratio of 1:2 W/W. Then ES-DBSA was dissolved in chloroform solution and added to Au/ODA
nanoparticles solution to obtain Au/ES-DBSA nanocomposite. FA sensors were prepared by depositing a film from ESDBSA
or Au/ES-DBSA on a working electrode and the potential was measured at FA different concentrations in Electrochemical
Results: FTIR and XRD confirmed the structure of ES-DBSA and Au/ES-DBSA. The obtained results reveal that the ESDBSA
nanosensor is an efficient sensor because it can recognize the low levels of FA starting from 0.06 ppm. The recorded
electrochemical oxidation current shows a linear direct relationship between the produced current and FA concentration
in case of ES-DBSA nanoparticles while it illustrates a fluctuating signal with lower sensitivity in the case of the
novel prepared nanocomposites (Au/ES-DBSA). This may be due to the gold capping agent (ODA), which in turn could
inhibit the role of DBSA and decrease the conductivity of the nanocomposite.
Conclusion: Herein we described the application of ES-DBSA and Au/ES-DBSA nanocomposite for the first time as a
novel, facile, and cheap method for electrochemical sensitive detection of formaldehyde. The gold capping agent ODA
hinders the ES-DBSA conductivity through interaction with the DBSA sulfo group.