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Abstract
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In this work, a novel thin film microextraction (TFME) 1, 2 method was developed using ZnO
nanoparticles (ZnO NPs) incorporated into polyamide (PA) nanocomposite. In this regard the ex-situ
prepared ZnO NPs 3 was dispersed into PA solution and the obtained solvent blend was deposited onto
cellulose paper applying solvent exchange method. The characterization of prepared ZnO NPs/PA
nanocomposite was performed applying energy dispersive X-ray spectroscopy (EDX), X-ray diffraction
(XRD) and scanning electron microscopy (SEM). The prepared thin film based on ZnO NPs/PA
nanocomposite was employed for ultrasound assisted thin film microextraction (USA-TFME) of some
organophosphorous pesticides (OPPs) as model compounds including fenthion, chlorpyrifos, fenithrothion,
phosalone, edifenphos and ethion in environmental water samples followed by gas chromatography-flame
ionization detector (GC-FID) determination. TFME is a relatively new approach based on membrane solid
phase microextraction (SPME) in sample preparation techniques which has exhibited more advantages over
SPME such as small thickness of the extraction phase, a larger surface area-to-volume ratio, higher
extraction rate and shorter equilibration time. Ultrasonic (US) radiation can be used in microextraction
techniques as a powerful tool to increase the speed of the mass transfer process of the solutes towards the
adsorbent surface 4, leading to enhance of the extraction efficiency in a shorter duration time 5. Important
parameters influencing the extraction and back-extraction steps of USA-TFME were optimized applying
orthogonal array Taguchi design. The developed methods limits of detection (LODs) were in the range of
0.05 to 0.3 ng mL and its linear dynamic ranges (LDRs) were 0.2-1000, 0.3-1000 and 1-1000 ng mL-1 for
all analytes. The method precision (RSD %) with three replicates experiments was in the range of 2.1 to
9.8% using spiked distilled water (100 ng mL ).
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