RESUMEN
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 cell kit. 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.
RESUMEN
Nanomaterials are promising in the field of optical sensors due to their unique properties. Emeraldine base of polyaniline (Nano EB-PANI) was prepared, characterized and applied as an optical formaldehyde sensor. FTIR data confirm the formation of the EB-PANI. TEM and SEM revealed the size and shape of the nanoscale EB-PANI. XRD showed that the obtained nano EB-PANI has a partial crystalline nature. The sensing mechanism is based on the reaction of formaldehyde with Nano EB-PANI- to form a complex as described by molecular modeling HF/3-21G** level of theory. Results showed that Nano EB-PANI- detect low concentrations of formaldehyde ranging from 0.0003 to 0.9 ppm in a dose-dependent manner. The molecular modeling theory analysis showed that formaldehyde could interact with the amine of EB-PANI in, ring 3 or 4 or both together. The binding energy and dipole moment of the interaction between formaldehyde and polyaniline nanosensor were calculated by HF/3-21g** level of theory. The interaction with ring 3-NH gives a less stable product with a high dipole moment 6.978 Debye comparing with 1.678 Debye for the product of formaldehyde interaction with the terminal ring 4-NH. The development of such novel EB-PANI nanosensor can be used as, reliable and sensitive formaldehyde sensor.