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Martinez Bueno M.J.,University of Almeria | Herrera S.,University of Almeria | Ucles A.,University of Almeria | Aguera A.,University of Almeria | And 6 more authors.
Analytica Chimica Acta | Year: 2010

This paper describes the development of an analytical procedure to determine malachite green (MG) residues in salmon samples using molecularly imprinted polymers (MIPs) as the extraction and clean-up material, followed by liquid chromatography-linear ion trap mass spectrometry (LC-QqQLIT-MS/MS). MG and two structurally related compounds, crystal violet (CV) and brilliant green (BG) were employed for the selectivity test. The imprinted polymers exhibited high binding affinity for MG, while CV and BG showed less binding capacity: 47% and 34%, respectively. The recovery values of MG in salmon samples fortified with leucomalachite green (LMG) were determined by measuring the amount of MG in the sample, after carrying out the oxidation reaction with 2,3-dichloro-5,6-dicyano-1,4-benzoquinone (DDQ), which converts the LMG back into chromic-form. The average recovery of MG in spiked salmon muscle over the concentration range 1-100ngg-1 was 98% with a relative standard deviation value (R.S.D.) below 12%. The method detection limits (MDLs) obtained for MG, CV, BG and their leuco-metabolites were in the range of 3-20ngkg-1 (ppt). © 2010 Elsevier B.V.

Leeman M.,MIP Technologies AB | Santacruz S.,San Francisco de Quito University
Analytical and Bioanalytical Chemistry | Year: 2011

Asymmetrical-flow field-flow fractionation combined with multiangle light scattering and refractive index detection has been revealed to be a powerful tool for starch characterization. It is based on size separation according to the hydrodynamic diameter of the starch components. Starch from a wide range of different botanical sources were studied, including normal starch and high-amylose and high-amylopectin starch. The starch was dissolved by heat treatment at elevated pressure in a laboratory autoclave. This gave clear solutions with no granular residues. Amylose retrogradation was prevented by using freshly dissolved samples. Programmed cross flow starting at 1.0 mL min-1 and decreasing exponentially with a half-life of 4 min was utilised. The starches showed two size populations representing mainly amylose and mainly amylopectin with an overlapping region where amylose and amylopectin were possibly co-eluted. Most of the first population had molar masses below 106 g mol-1, and most of the second size population had molar masses above 107 g mol-1. Large differences were found in the relative amounts of the two populations, the molar mass, and hydrodynamic diameters, depending on the plant source and its varieties. © 2010 Springer-Verlag.

Chimuka L.,University of Witwatersrand | van Pinxteren M.,Helmholtz Center for Environmental Research | Billing J.,MIP Technologies AB | Yilmaz E.,MIP Technologies AB | Jonsson J.T.,Lund University
Journal of Chromatography A | Year: 2011

A selective extraction technique based on the combination of membrane assisted solvent extraction and molecularly imprinted solid phase extraction for triazine herbicides in food samples was developed. Simazine, atrazine, prometon, terbumeton, terbuthylazine and prometryn were extracted from aqueous food samples into a hydrophobic polypropylene membrane bag containing 1000 μL of toluene as the acceptor phase along with 100. mg of MIP particles. In the acceptor phase, the compounds were re-extracted onto MIP particles. The extraction technique was optimised for the type of organic acceptor solvent, amount of molecularly imprinted polymers particles in the organic acceptor phase, extraction time and addition of salt. Toluene as the acceptor phase was found to give higher triazine binding onto MIP particles compared to hexane and cyclohexane. Extraction time of 120. min and 100. mg of MIP were found to be optimum parameters. Addition of salt increased the extraction efficiency for more polar triazines. The selectivity of the technique was demonstrated by extracting spiked cow pea and corn extracts where clean chromatograms were obtained compared to only membrane assisted solvent extraction or only molecularly imprinted solid phase extraction. The study revealed that this combination may be a simple way of selectively extracting compounds in complex samples. © 2010 Elsevier B.V.

Kecili R.,MIP Technologies AB | Kecili R.,TU Dortmund | Billing J.,MIP Technologies AB | Leeman M.,MIP Technologies AB | And 4 more authors.
Separation and Purification Technology | Year: 2013

The present study describes an easy and efficient approach for the removal of methyl p-toluenesulfonate, a potentially genotoxic impurity (GTI) from a model active pharmaceutical ingredient (API), 21-chlorodiflorasone. For this purpose, several polystyrene-divinylbenzene based and silica based scavengers were tested and the scavengers which showed the highest removal efficiency and selectivity were chosen for further evaluations. The time course of GTI and API scavenging and also the capacities of different scavengers were studied in this paper. The best GTI removal performance and selectivity was obtained with silica based Si-Trisamine and macroporous polystyrene-divinylbenzene based MP-Trisamine, both leading to 100% methyl p-toluenesulfonate removal with no loss of 21-chlorodiflorasone. Non-specifically bound API could be recovered quantitatively by using 2-propanol:THF (1:1). © 2012 Published by Elsevier B.V. All rights reserved.

Yilmaz E.,MIP Technologies AB | Billing J.,MIP Technologies AB | Nilsson C.,MIP Technologies AB | Boyd B.,Straumann | And 5 more authors.
Advances in Biochemical Engineering/Biotechnology | Year: 2015

The crossreactivity of molecularly imprinted polymers (MIPs) and its practical implications are discussed. Screening of MIP libraries is presented as a fasttrack route to discovery of resins selective towards new targets, exploiting the fact that MIPs imprinted with one type of template molecule also show recognition to related and sometimes also to apparently unrelated molecules. Several examples from our own and others’ studies are presented that illustrate this crossreactivity and the pattern of recognition is discussed for selected examples. © 2015, Springer International Publishing Switzerland.

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