Determination Of Organophosphorus Pesticide Residues In Several Local Vegetables Using Solid Phase Microextraction Coupled With Gas Chromatography
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Date
2016-03
Authors
Sapahin, Haizarul Aida
Journal Title
Journal ISSN
Volume Title
Publisher
Universiti Sains Malaysia
Abstract
A simple analytical method based on solid-phase microextraction (SPME)
followed by gas chromatography-flame photometric detection (GC-FPD) for the
simultaneous determination of eleven organophosphorus pesticide residues
(ethoprophos, sulphotep, diazinon, tolclofos-methyl, fenitrothion, chlorpyrifos,
isofenphos, methidathion, ethion, triazophos, leptophos) in three types vegetables
samples (cabbage, kale and mustard) was developed. Important parameters that
influence the extraction efficiency (i.e., fibre type, extraction modes, extraction time,
salt addition, desorption time and temperature) were systematically investigated.
Four types of commercially available fibres namely 50/30 μm
divinylbenzene/carboxen/polydimethylsiloxane (DVB/CAR/PDMS), 65 μm
polydimethylsiloxane/divinylbenzene (PDMS/DVB), 100 μm polydimethylsiloxane
(PDMS), and 85 μm polyacrylate (PA) were evaluated. PA fibre exhibited the best
performance and was used for the rest of the studies. The optimized extraction
conditions were: extraction time, 30 min at room temperature; stirring speed, 1275
rpm; salt content, 10% NaCl; desorption time and temperature, 11 min at 260 °C; and
no pH adjustment of the sample extract. The method was validated over the range
0.1–100 μg L-1. Repeatabilities were satisfactory, ranging between 2.44–17.9% for
all analytes. The limits of detection and quantitation ranged from 0.01–0.14 and
0.03–0.42 μg L-1, respectively. The method was applied to 22 locally produced
vegetables (cabbage, kale and mustard). Chlorpyrifos (0.22–1.68 μg kg-1) was the most detected pesticide in the tested samples. However, the obtained values are
lower than the maximum residue limits (MRLs) as stipulated in the Food Act &
Regulations of Malaysia.
Description
Keywords
Solid-phase microextraction