Abstract:The liquid chromatographic separation of permethrin enantiomers on chiral beta-cyclodextrin-based stationary phase has been investigated. All four enantiomers are obtained by using simple methanol and water mobile phase, under gradient mode. The method was optimized and validated. The relationship between temperature and chromatographic parameters: k' (capacity factor), alpha (separation factor) and Rs (resolution factor) was studied. Van't Hoff's curves for each enantiomer were plotted for temperature range 2… Show more
“…Therefore, characterising the stereochemistry of their interaction with potential analyte molecules is important. Although CDs are often employed in chiral separations [9][10][11], they are equally applicable to separations involving other molecular geometry differences such as structural and positional isomers [12][13][14]. However, these studies focus on particular systems and there is no comparative study of the influence of The van der Waals term is the main contribution to the total energy, particularly inside the cavity, so it directly determines the configuration of the inclusion complex [15][16][17].…”
“…Therefore, characterising the stereochemistry of their interaction with potential analyte molecules is important. Although CDs are often employed in chiral separations [9][10][11], they are equally applicable to separations involving other molecular geometry differences such as structural and positional isomers [12][13][14]. However, these studies focus on particular systems and there is no comparative study of the influence of The van der Waals term is the main contribution to the total energy, particularly inside the cavity, so it directly determines the configuration of the inclusion complex [15][16][17].…”
“…Chiral LC-MS/MS, first proposed in this work for determination of PM enantiomers, was undertaken by using a chiral stationary phase (β-cyclodextrin covalently bonded to silica particles, ChiraDex) previously reported for their determination by LC-UV . Resolutions achieved in that study were 1.32 and 2.27 for the enantiomers of trans- and cis-PM, respectively, using methanol–water mixtures as the mobile phase and a chromatographic run of 46 min …”
Section: Resultsmentioning
confidence: 99%
“…Enantiomers of PM have been separated by both normal , and reverse LC phases prior to their detection by UV photometry. Chiral gas chromatography (GC) using β-cyclodextrin stationary phases allows the separation of ( 1S )- and ( 1R )-cis-PM but not ( 1S )- and ( 1R )-trans-PM .…”
Permethrin (PM) is one of the chiral insecticides most widely used around the world. The significant differential toxicity of its four enantiomers and its important adverse effects on human health highlights the need for determination of PM enantiomers. The aim of this work was to develop the first enantioselective method for quantification of PM in fruits and vegetables. The method is based on the extraction of PM enantiomers in supramolecular solvents with restricted access properties (SUPRAS-RAM) and their separation/detection by chiral liquid chromatography-tandem mass spectrometry (LC-MS/MS) which is first reported in this article. SUPRAS-RAM-based extraction is proposed as an innovative treatment approach that drastically reduces solvent consumption and avoids the need for sample cleanup. Extraction of PM enantiomers is quick (vortexing for 5 min) and efficient (recoveries 93−107%). The method is sensitive (quantification limits from 1.0 to 1.2 μg kg −1 ) and suitable for control of PM enantiomers in agri-food products.
“…Permethrin (3-Phenoxybenzyl-cis,trans-(1RS)-3-(2,2dichlorovinyl)-2,2-dimethylcyclopropanecarboxylate) is one of the widely used pyrethroid insecticides for elimination of the insects dangerous to agriculture and human lives [4][5][6]. Similar to the organochlorine pesticide DDT, permethrin acts by interfering with sodium channels to disrupt the function of neurons in the nervous system [7,8]. Pyrethroid insecticides, including permethrin, are lipophilic compounds that appear in a very low concentration level in aquatic environments due to their low water solubility [9,10].…”
Background Extensive use of high-efficiency pyrethroid pesticides as pest-control agents lead to remarkable adsorption and release of these materials in soil and aquatic environment which could have serious adverse effects on water and food chain quality as well as human health. In this study, a molecularly imprinted polymer was synthesized and used as a selective sorbent in the sample preparation procedure in order to facilitate sensitive and quantitative exposure assessment of insecticide permethrin. Methods Molecular imprinted nanoparticles were prepared by precipitation polymerization technique using 1:4:20 mmol ratio of the template, functional monomer, and cross-linker, respectively, as well as 80 mL of chloroform as progen solvent. The obtained nanoparticles were characterized by field emission scanning electron microscopy (FESEM) and Fourier transform infrared spectrometry (FT-IR). The optimization of critical variables in the MISPE process was done using the central composite design (CCD) of the response surface methodology. Results Quadratic regressional models were developed to correlate the response and independent variables and the analysis of variance (ANOVA) verified the excellent fitting of proposed models for experimental data. Optimum conditions for the highest MISPE yield were selected as follow: sorbent mass of 7.71 mg, sample pH 5.58 and 5.68 for cis and trans-permethrin, respectively, sample flow rate of 0.6 mL/min, as well as 5 and 3.94 mL of methanol/acetic acid at the flow rate of 2 mL/min as elution solvents for cis and trans-permethrin, respectively. Under optimized conditions, the linear range was obtained 20-120 μg/L (R2 = 0.99) and the detection limits were 5.51 and 5.72 μg/L for cis and trans-permethrin, respectively. Analysis of real samples demonstrated the high extraction efficiency of designed protocol ranging from 93.01 to 97.14 with the relative standard deviation (RSD) less than 4.51%. Conclusions The satisfactory results confirmed the reliability and efficiency of the proposed method for trace analysis of permethrin isomers in biological and environmental samples.
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