Search results for "molecular imprinting"

Molecularly imprinted polymer-based device for field collection of oral fluid samples for cocaine identification.

2020

In this paper, a low-cost, rapid, easy, and potentially portable tool for the identification of cocaine and its semi-quantitative determination in oral fluid has been proposed. A field collection device has been designed, based on a cotton pad with an indicator and a molecularly imprinted polymer (MIP) sorbent, to selective retain cocaine from oral fluid components. After sample collection, cocaine is transferred by using phosphate buffer to the MIP and then eluted with 2-propanol. The obtained extract is analysed by ion mobility spectrometry (IMS), providing a cut-off value of 20 µg L-1 that identifies 100 % true-positive and 95 % true-negative samples. The MIP-IMS procedure has been valid…

Effect of solvents on the selectivity of terbutylazine imprinted polymer sorbents used in solid-phase extraction

2002

A solid-phase extraction sample preparation method using a molecularly imprinted polymer (MIP) selective for the triazine type pesticide terbutylazine has been developed. The method involves preconcentration from large volumes of water samples on a C18 disk coupled to selective clean-up on the MIP. The method has been optimised by studying the recovery and retention of terbutylazine and some other structurally related triazine derivates as a function of the selective washing solvent used. The effect of the water content of the selective washing solvent was also investigated on the recovery of the MIP. River water samples were analysed with the coupled technique, and efficient clean-up of th…

Development of a molecularly imprinted monolithic polymer disk for agitation-extraction of ecgonine methyl ester from environmental water

2019

Abstract In this study, a new extraction approach based on rotating molecularly imprinted polymer (MIP) disks was developed. The preparation procedure of MIP-disk is simple. Firstly, in order to immobilize MIP onto the surface of polytetrafluoroethylene (PTFE) disk, previous modification and vinylization steps of this fluoropolymer were conducted. Then, MIP synthesis was done by in situ polymerization. The resulting MIP was characterized by Fourier-transform infrared spectroscopy and scanning electron microscopy. Afterwards, two ring magnets were placed in the sides of the MIP-disk to integrate the stirring and preconcentration of sample in just one step. To demonstrate the feasibility of t…

Selective solid-phase extraction of organophosphorus pesticides and their oxon-derivatives from water samples using molecularly imprinted polymer fol…

2020

Abstract A molecularly imprinted polymer was synthesized and characterized to be used as solid-phase extraction sorbent for simultaneous chlorpyrifos and diazinon and their oxon derivatives. Several imprinted polymers were prepared and evaluated in a retention study of these analytes compared with a non-printed polymer. Several parameters affecting the extraction of imprinted polymer such as washing solvent, composition and volume of the eluting solvent and sample volume, were also investigated. Under the optimum conditions, the developed method provided satisfactory limits of detection ranging between 0.07 µg L−1 to 0.12 µg L−1 and the material showed an excellent reusability (> 50 reuses)…

Screening of oxazepine indole enantiomers by means of high performance liquid chromatography with imprinted polymer stationary phase.

2004

Chromatographic enantiomer separations of different oxazepine indole derivatives were performed using a molecularly imprinted polymer. A 5aR,12R,13S-trans-6,6-dimethyl-12,13-dihydro-6H-5a, 1 3-methanoindolo[2,1-b][1,3]naphthoxazepine-12-carboxamide enantiomerderivative was used as a template and the resultant polymer has shown enantiomer recognition for series of template related compounds. The mechanistic description of the chiral discrimination process is scrutinised, comparing the discrimination between the different conformations and substituents of the oxazepine indoles.

Determination of non-steroidal anti-inflammatory drugs in water and urine using selective molecular imprinted polymer extraction and liquid chromatog…

2016

Abstract A selective solid-phase extraction was employed for the improvement of the determination of non-steroidal anti-inflammatory drugs (NSAIDs) in continental water and urine samples. Ketoprofen, naproxen, diclofenac, and ibuprofen were selected as target analytes due to they are the most frequently administered and consumed NSAIDs. These compounds were extracted using molecular imprinted polymers and determined by liquid chromatography with diode array (DAD), and tandem-mass spectrometry (MS–MS) detectors. Performance of DAD and MS–MS detectors was evaluated throughout this study. The obtained limits of quantification, after a 50-fold preconcentration solid-phase extraction, varied fro…

The application of molecular imprinting technology to solid phase extraction

2001

In parallel to a long lasting search for universal multi-purpose sorbents, the area of solid phase extraction (SPE) is recently experiencing a rapid development of new types of tailor-made class specific or compound-specific sorbents which are designed to respond to the increasing demand for selectivity and efficiency in sample clean-up prior to quantification. An important issue here is the enrichment and clean-up of complex samples, such as environmental waters, sediments, biofluids and foodstuffs prior to detection. This because the analyte is often present in low concentration in a complex mixture of similar compounds and therefore needs to be isolated and enriched in order to be detect…

Layer-by-Layer Grafting of Molecularly Imprinted Polymers via Iniferter Modified Supports

2002

Imbibition of Femtoliter-Scale DNA-Rich Aqueous Droplets into Porous Nylon Substrates by Molecular Printing

2019

This work presents the first reported imbibition mechanism of femtoliter (fL)-scale droplets produced by microchannel cantilever spotting (μCS) of DNA molecular inks into porous substrates (hydrophilic nylon). Differently from macroscopic or picoliter droplets, the downscaling to the fL-size leads to an imbibition process controlled by the subtle interplay of evaporation, spreading, viscosity, and capillarity, with gravitational forces being quasi-negligible. In particular, the minimization of droplet evaporation, surface tension, and viscosity allows for a reproducible droplet imbibition process. The dwell time on the nylon surface permits further tuning of the droplet lateral size, in acc…

Magnetic molecularly imprinted polymer for the simultaneous selective extraction of phenoxy acid herbicides from environmental water samples

2022

[EN] A selective magnetic molecularly imprinted polymer (MMIP) was synthetized with 4-chloro-2-methylphenoxyacetic acid as template and 4-vinylpiridine as monomer in presence of vinylized magnetite nanoparticles. Scanning electron microscopy, nitrogen adsorption-desorption isotherms, Fourier transform infrared spectrometry and vibrating sample magnetometry were applied to characterize the resulting material. The synthesized MMIP was applied as sorbent in magnetic molecularly imprinted solid-phase extraction (MMISPE) for selective extraction of a mixture of the five herbicides 4-chloro-2-methylphenoxyacetic acid (MCPA), 4-(4-chloro-2-methylphenoxy)butyric acid (MCPB), mecoprop (MCPP), fenoxa…