Mehdi Taghdiri; Setareh Zakeri-Shahvari; Hamidreza Zare-mehrjardi
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.
Mayur Sanjay Tekade; Pallavi M Patil
Abstract
The purpose of this study was to create, optimise, and validate a high-performance thin layer chromatographic (HPTLC) method for identifying Molnupiravir (MOL) and its impurity (IMP-MOL). (3aR,4R,6R,6aR) -6-(4-(hydroxyamino) -2-oxopyrimidin-1(2H)-yl) Molnupiravir A is 2,2 dimethyltetrahydrofuro [3,4-d][1,3]dioxol-4-yl)methyl ...
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The purpose of this study was to create, optimise, and validate a high-performance thin layer chromatographic (HPTLC) method for identifying Molnupiravir (MOL) and its impurity (IMP-MOL). (3aR,4R,6R,6aR) -6-(4-(hydroxyamino) -2-oxopyrimidin-1(2H)-yl) Molnupiravir A is 2,2 dimethyltetrahydrofuro [3,4-d][1,3]dioxol-4-yl)methyl isobutyrate (MOL IMP) Over concentration ranges of 0.1 µg/band to 0.6 µg/band and 0.02 to 0.6 µg/band, the proposed technique was employed to analyse Molnupiravir and its impurity, with mean percentage recovery of 99.92% ±1.521 and 99.28% ±2.296, respectively. This method has been done with the separation of two components and ends with the densitometric measurement of the separated peaks at 276 nm. The separation was done on silica gel HPTLC F254 plates with a Toluene: n-Butanol: Methanol: Water developing system (5:3:1.5:0.5, by volume). The MOL was kept under conditions like oxidative, hydrolytic, thermal stress, and photolytic tests that the International Conference on Harmonization (ICH) requires. In acid, alkali, and oxidative hydrolysis, the MOL was unstable, but it was not affected by acidic, heat or UV light. The alkaline degradation of Molnupiravir was studied using the proposed HPTLC approach. The degradant are separated using HPTLC method, and their structures are confirmed using IR, MS, and NMR spectrum data.
Majid Haji Hosseini; Mohammad Reza Rezaei; Mohammad Rezaee; Peyman Asaadi; Khatereh Ashtari
Volume 1, Issue 1 , March 2014, , Pages 20-28
Abstract
This study propose a new analytical protocol for the determination of benzene, xylene, toluene and styrene in water samples using homogeneous liquid-liquid microextraction via flotation assistance (HLLME-FA) technique followed by gas chromatography-mass spectrometry (GC-MS). In this research, a special ...
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This study propose a new analytical protocol for the determination of benzene, xylene, toluene and styrene in water samples using homogeneous liquid-liquid microextraction via flotation assistance (HLLME-FA) technique followed by gas chromatography-mass spectrometry (GC-MS). In this research, a special extraction cell was designed to facilitate collection of the low-density solvent extraction. No centrifugation was required in this procedure. The water sample solution was added into the extraction cell which contained an appropriate mixture of extraction and homogeneous solvents. By using air flotation, the organic solvent was collected at the conical part of the designed cell. The effects of different variables on the efficiency of the extraction were studied simultaneously using experimental design. Response surface methodology was applied to investigation the optimum conditions of each variable. Using optimized variables in the extraction process, for all target analytes, the detection limits, the precisions and the linearity of the method were found in the range of 0.8-8.2 ng mL-1, 3.09-7.96% (RSD, n=4) and 1-100 ng mL-1, respectively. The headspace method was used for the accuracy of comparison. The performance of the method was evaluated for extraction and determination of analytes in water samples and satisfactory results were obtained (RSD ≤10.06 %).
