Setareh Zakeri-Shahvari; Hamidreza Zare-mehrjardi; Mehdi Taghdiri
Abstract
The principle of this research is based on the development of multi-residue method by QuEChERS sample preparation follow by gas chromatography with mass spectrometric detection in the selected ion monitoring mode (GC–MS-SIM) for the routine analysis of 42 pesticides in rice samples. The rice samples ...
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The principle of this research is based on the development of multi-residue method by QuEChERS sample preparation follow by gas chromatography with mass spectrometric detection in the selected ion monitoring mode (GC–MS-SIM) for the routine analysis of 42 pesticides in rice samples. The rice samples were initially extracted with acetonitrile, and the targeted pesticides were purified following the dispersive solid phase extraction (d-SPE) cleanup method. The calibration curve for each analyte quantified by matrix-matched calibration was linear over the concentration range of 10.0–1000.0 μg L−1 with a correlation coefficient range between 0.990 and 0.999. Mean recoveries from three replicates ranged from 79% to 112%, with satisfactory precision (RSD<7%). The limit of detection and the limit of quantification were in the range of 3.04–12.52 μg L−1 and 10.14–41.76 μg L−1 respectively, for all 42 pesticides.
Mohammad Ali Karimi; Abdolhamid Hatefi-Mehrjardi; Alireza Mohadesi; Sayed Zia Mohammadi; Mehdi Taghdiri; Javad Yarahmadi; Havva Mahmoodian; Shahla Nezhad Khorasani
Volume 1, Issue 1 , March 2014, , Pages 7-11
Abstract
In this work, a new, simple and fast method for the solid phase extraction-spectrophotometric determination of phosphate using cetyltrimethyl ammonium bromide immobilized on alumina-coated magnetite nanoparticles (CTAB@ACMNPs) has been developed. The determination of phosphate is based on the molybdenum ...
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In this work, a new, simple and fast method for the solid phase extraction-spectrophotometric determination of phosphate using cetyltrimethyl ammonium bromide immobilized on alumina-coated magnetite nanoparticles (CTAB@ACMNPs) has been developed. The determination of phosphate is based on the molybdenum blue method which was monitored at λmax of 810 nm. MNPs and ACMNPs characterized by SEM, VSM, and XRD spectroscopy. This method avoided the time-consuming column-passing process of loading large volume samples in traditional SPE through the rapid isolation of CTAB@ACMNPs with an adscititious magnet. Under the optimal experimental conditions, the preconcentration factor (PF), detection limit (DL), linear range (LR) and relative standard deviation (RSD) of phosphate were 80 (for 400 mL of sample solution), 0.038 µg mL−1, 0.8-10.0 µg mL−1 and 2.5 % (for 5.0 µg mL-1, n=7), respectively. The proposed method was successfully applied to the separation/preconcentration and determination of phosphate in different water samples and suitable recoveries were obtained.