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Abstract
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In this research, a novel nanocomposite based
on incorporation of graphene oxide (GO) into polyamide
(PA) was prepared by solvent blending method and subsequently
it was coated on stir bar substrate through solvent
exchange method. The morphology and surface characteristic
of PA- and GO/PA-coated stir bars were investigated
using scanning electron microscopy (SEM). The prepared
GO/PA nanocomposite-based stir bar was applied as an
extraction device for stir bar sorptive extraction (SBSE)
of organophosphorous pesticides (OPPs) including chlorpyrifos,
ethion, and phosalone in fruit juice and vegetable
samples followed by gas chromatography–flame ionization
detector (GC-FID) detection. The effect of GO doping
level into the nanocomposite on the extraction capability
of the coating was investigated. Important factors influencing
the extraction and desorption processes including
extraction time, salt content, sample volume, pH, desorption
solvent, its volume, and desorption time were studied
and optimized applying central composite design (CCD).
Limits of detection (LOD) and linear dynamic ranges of the
method were in the range of 0.3–1 ng mL−1 and 1–1000
and 3–1000 ng mL−1, respectively. The method precision
(RSD%) with four replicate determinations was in the
range of 6.2–9.1% for distilled water at the concentration
level of 100 ng mL−1. The developed method was successfully
applied to various fruit juices and vegetable samples,
while the relative recoveries (RR %) were found to be in
the range of 82.0–95.6%.
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