A polythiophene–silver nanocomposite for headspace needle trap extraction

• A nanocomposite consisting of silver–polythiophene was synthesized.
• Ag NPs were prepared in microemulsions with n-decane as the oil phase.
• Polythiophene was synthesized by chemical oxidative polymerization in the presence of anhydrous ferric chloride.
• The applicability of the sorbent was examined by needle trap extraction of some PAHs in aqueous samples.

A nanocomposite consisting of polythiophene–silver was prepared and implemented as a desired sorbent for headspace needle trap extraction. Colloidal silver nanoparticles (Ag NPs) with narrow size distribution and high stability were synthesized in water–in–oil microemulsion. This simple procedure was adapted to prepare highly monodispersed Ag NPs, starting from an initial synthesis in sodium bis(2-ethylhexyl) sulfosuccinate (AOT) reverse micelles. Polythiophene (PT) was synthesized by chemical oxidative polymerization in the presence of anhydrous ferric chloride while its polymeric structure was confirmed by Fourier transform infrared spectrometry (FTIR). Eventually, the prepared PT was dispersed in an AOT/n-decane solution containing Ag NPs for 1 h in which the NPs were adsorbed on the polymer surface. The dynamic light scattering (DLS) analysis of NPs solution revealed that the monodisperse Ag NPs have been synthesized successfully with the size distribution below 10 nm. Other instrumentations such as scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS) and atomic absorption spectrometry (AAS) confirmed the fabrication of the PT–Ag nanocomposite. The applicability of the synthesized sorbent was examined by needle trap extraction of some polycyclic aromatic hydrocarbons (PAHs) in aqueous samples in conjunction with gas chromatography–mass spectrometry detection (GC–MS). Important parameters influencing the extraction process were optimized. The linearity for all analytes was in the concentration range of 0.01–10 ng mL−1. The limits of detections were in the range of 0.002–0.01 ng mL−1, using time–scheduled selected ion monitoring (SIM) mode while the RSD% values (n = 3) were all below 12%. The developed method was successfully applied to real water samples obtained from different rivers and Persian Gulf, while the relative recovery percentages were in the range of 85–103%.