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Development of Headspace Solid-Phase Microextraction Method for the Analysis of Pesticide Residues in Fruit and Vegetable Samples using OFAT Design
ABDULRA’UF, LUKMAN BOLA; LAWAL, AMUDALAT RANTI & TAN, GUAN HUAT
Abstract
A headspace solid-phase microextraction (HS-SPME) method was developed as
a preliminary investigation using univariate approach for the analysis of 14 multiclass pesticide
residues in fruits and vegetable samples. The gas chromatography mass spectrometry
parameters (desorption temperature and time, column flow rate, interface temperature) and solid
phase microextraction parameters (fiber coating type, extraction temperature and time, pH, salt
addition, stirring rate, dilution factor, organic solvent type and amount) were all investigated
and optimized. The optimum values for the optimized parameters are as follows: Injection
Temperature, 270 °C; Interface temperature, 300 °C; Column flow rate, 1.3 mL/min; Fiber
coating, PDMS/DVB; Extraction time, 30 mins; Extraction temperature, 60 °C; Stirring rate,
300 rpm; Salt addition, 10% (v/w) NaCl; pH, 7; Desorption time, 7 min; Desorption
temperature, 270°C; Organic solvent 3 % (methanol/acetone, 21:79%). The optimization of the
mixture of organic solvents was optimized using design of experiment (DOE) with simplex
lattice, designed using Minitab Statistical Software®. The developed method was then applied
to the analysis of samples of apple, tomato, broccoli, lettuce, grape, cucumber, cabbage and
pear. The investigated pesticides were found to be below the maximum residue levels, while
some were not found. This shows that the fruit and vegetable samples are safe for consumption
and do not pose any health risk for consumers.
Keywords
Univariate design; Simple lattice design; design of experiment; GC-MS; HS-SPME
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