Molecularly imprinted solid-phase extraction combined with ultrasound-assisted dispersive liquid–liquid microextraction for the determination of four Sudan dyes in sausage samples
College of Pharmacy, Hebei University, Baoding, China. The Analyst
(Impact Factor: 4.11).
06/2011; 136(12):2629-34. DOI: 10.1039/c0an00951b
A simple and highly selective molecularly imprinted solid-phase extraction (MISPE) combined with ultrasound-assisted dispersive liquid-liquid microextraction (DLLME) was developed for the determination of four Sudan dye (I, II, III, and IV) residues in sausage products. The novel molecularly imprinted microspheres (MIMs) synthesized by aqueous suspension polymerization using phenylamine-naphthol as the dummy template show high affinity to the four Sudan dyes and were applied as selective sorbents of MISPE-DLLME to overcome the drawbacks of template leakage in quantitative analysis. Good linearity was obtained in a range of 0.005-2.0 μg g(-1) and the average recoveries of the four Sudan dyes at three spiked levels ranged from 86.3 to 107.5%. The MISPE-DLLME-HPLC protocol significantly improved the purification and enrichment of the analytes and eliminated the template leakage of the conventional MISPE on quantitative analysis.
Available from: Mohamed Abdel-Rehim
- "This was performed through a multi-step process . Molecularly imprinted solid-phase extraction in combination with dispersive liquid–liquid microextraction (MISPE–DLLME) and microextraction (MIP SPME–DLLME) are new strategies in sample preparation for extraction and screening of various ranges of analytes in biological, environmental and food analysis      . It seems that development of a simple, single-step, selective, stable method with a longer lifetime for the modification of hollow fiber membrane is a crucial issue. "
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ABSTRACT: In the present study, the modification of a polysulfone hollow fiber membrane with in situ molecularly imprinted sol-gel process (as a novel and one-step method) was prepared and investigated. 3-(propylmethacrylate)trimethoxysilane (3PMTMOS) as an inorganic precursor was used for preparation of molecularly imprinted sol-gel. The modified molecularly imprinted sol-gel hollow fiber membrane (MSHM) was used for the liquid-phase microextraction (LPME) of hippuric acid (HA) in human plasma and urine samples. MSHM as a selective, robust, and durable tool was used for at least 50 extractions without significant decrease in the extraction efficiency. The non-molecularly imprinted sol-gel hollow fiber membrane (NSHM) as blank hollow fiber membrane was prepared by the same process, only without HA. To achieve the best condition, influential parameters on the extraction efficiency were thoroughly investigated. The capability of this robust, green, and simple method for extraction of HA was successfully accomplished with LC/MS/MS. The limits of detection (LOD) and quantification (LOQ) in human plasma and urine samples were 0.3 and 1.0nmolL(-1), respectively. The standard calibration curves were obtained within the concentration range 1-2000nmolL(-1) for HA in human plasma and urine. The coefficients of determination (r(2)) were ≥0.998. The obtained data exhibited recoveries were higher than 89% for the extraction of HA in human plasma and urine samples.
Copyright © 2015 Elsevier B.V. All rights reserved.
Journal of chromatography. B, Analytical technologies in the biomedical and life sciences 07/2015; 995. DOI:10.1016/j.jchromb.2015.05.005 · 2.73 Impact Factor
Available from: Zhong Zhang
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ABSTRACT: A novel colorimetric sensor for cholesterol assay was constructed by combining a molecular imprinting technique with photonic crystals. The molecularly imprinted photonic hydrogel (MIPH) film was prepared by a non-covalent, self-assembly approach using cholesterol as a template molecule, and exhibited a highly ordered three-dimensional macroporous structure characterized by scanning electron microscopy under the optimized imprinting conditions. Various factors affecting rebinding of cholesterol are discussed along with recognition specificity studies on its analogues of stigmasterol and ergosterol through estimation of UV-Vis and electrochemical impedance spectroscopy. The MIPH film generated a significantly readable optical signal directly self-reporting within less than 2 min upon binding cholesterol. The colorimetric measurement of cholesterol concentration strongly relies on the fact that the blue shift effect of the Bragg diffraction peak of the MIPH is gradually enlarged with the increase of cholesterol amounts. The detection level approached 10−13 g mL−1, which is comparable to that of fluorescence measurements. The simultaneous possession of high selectivity, high sensitivity, high stability, easy operation and being label-free enables this sensor to be potentially applicable for rapid on-site detection of trace cholesterol.
Journal of Materials Chemistry 11/2011; 21(48):19267-19274. DOI:10.1039/C1JM14230E · 7.44 Impact Factor
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ABSTRACT: Dispersive liquid-liquid microextraction (DLLME) is a relatively new sample pretreatment method in which the acceptor-to-donor phase ratio is greatly reduced. This technique is based on the dispersion of the extraction solvent into the sample in order to enlarge the contact area between the extractant and the solution so that the equilibrium state is achieved very fast. Conventional DLLME works in a ternary component-system mode, in which a high density and hydrophobic solvent (extractant) is dissolved in a disperser solvent that must be miscible with both extractant and sample solution. The mixture is injected into the sample in which fine extraction-solvent microdroplets are formed and hydrophobic analytes can easily migrate into the extractant phase. Thereafter, the phases can be separated by centrifugation and the settled, enriched extractant phase can be subjected to instrumental analysis. DLLME found wide acceptance since its introduction in 2006, because of several advantages including simplicity, rapidity of operation, low consumption of organic solvents and reagents, low cost, high enrichment factors from low volumes of samples, and ease of method development that made it available to virtually all analytical laboratories. Up to now, DLLME is combined with different instrumental analytical techniques as well as other sample preparation methods.
Comprehensive Sampling and Sample Preparation, 01/2012: pages 181-212; , ISBN: 9780123813749
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