Electromembrane extraction of peptides (original) (raw)
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Electromembrane extraction of peptides - Fundamental studies on the supported liquid membrane
Journal of Separation Science, 2011
A large screening of different components in the supported liquid membrane (SLM) in electromembrane extraction (EME) was performed to test the extraction efficiency on eight model peptides. Electromembrane extraction from a 500 mL acidified aqueous sample containing the model peptides in the concentration 10 mg/mL was used. Extraction time was 5 min with an electric potential of 10 V and 900 rpm agitation of the sample vial. The samples were extracted through a hollow fiber-based SLM with different compositions of organic solvents and carriers. A small volume of acidified acceptor solution (25 mL) was after extraction analyzed directly, or with some dilution, on CE or HPLC. This article has identified mono-or di-substituted phosphate groups as the prominent group of carrier molecules needed to obtain acceptable recoveries. For the organic solvents, primary alcohols and ketones have shown promise regarding recovery and reproducibility, with some differences in selectivity. A new composition of the SLM, namely 2-octanone and tridecyl phosphate (90:10 w/w) has proved to give higher extraction recoveries and lower standard deviation than SLMs previously reported in the literature.
Electromembrane extraction: a new technique for accelerating bioanalytical sample preparation
Bioanalysis, 2011
The recent societal requirements to explore more environmentaly friendly solutions in the field of sample preparation have gained increasing focus during recent years. A reduction in the consumption of hazardous organic solvent owing to environmental and cost perspectives, small amounts of sample available and time reduction, have been major incentives for scientists to miniaturize existing sample preparation methods. Some of these challenges were addressed by the introduction of electromembrane extraction (EME), a totally new extraction principle where a potential difference is applied across a thin organic membrane immobilized in the pores in the wall of a porous polypropylene membrane. The potential difference is utilized to extract charged analytes of interest from the sample, across the organic membrane, and into an aqueous acceptor solution present inside the lumen of the hollow fiber. This article focuses on the potential of EME in bioanalysis, including discussions of EME pe...
Supported liquid membrane extraction of peptides
Acta biochimica Polonica, 2001
The application of supported liquid membrane (SLM) extraction for the enrichment of short peptides is presented. The extraction efficiency is dependent on the pH of donor phase and salt concentration in acceptor phase. Moreover, the extraction efficiency is also influenced by the peptide amino-acid sequence and hydrophobicity.
Anal. Methods, 2015
ABSTRACT In the present work, for the first time, cylindrical electrode that surrounded hollow fiber membrane was introduced in electromembrane extraction (EME). The setup introduced produces an efficient, inexpensive, stable, and reproducible method for increasing extraction efficiency of ionizable compounds from different matrices. The method was applied for extraction of diclofenac and mefenamic acid as model analytes from biological fluids. Effective parameters on EME of the analytes such as extraction time, applied voltage, and composition of acceptor/donor phases were investigated and optimized using the experimental design. Under optimized conditions, relative recoveries in the range of 94–105 and preconcentration factors in the range of 50–355 were obtained in various biological matrices. The linear dynamic range of 2.5–500 µg L−1 (with correlation coefficient better than 0.9986) and limit of detection of 0.25 µg L −1 were obtained for both of the analytes in plasma and urine samples. The figures of merit of EME with cylindrical electrode were compared with the results obtained from conventional EME.
Extraction of short peptides using supported liquid membranes
Desalination, 2002
Studies of extraction of short peptides using supported liquid membranes containing Aliquat 336 as a carrier are presented. The extractions are carried out from an aqueous donor phase with pH ≥ 10 to an acceptor phase containing salt. The mass transfer is driven by the gradient of salt concentration between these phases. The extraction efficiency is dependent on the composition of water phases, the type and concentration of counter-ion in the stagnant acceptor phase and the flow rate of the donor phase. Moreover, it is also influenced by the concentration and structure of the examined peptides.
Low-voltage electromembrane extraction of basic drugs from biological samples
Journal of Chromatography A, 2008
The present work has for the first time demonstrated electromembrane extraction (EME) at voltages obtainable by common batteries. Five basic drugs were extracted from acidified aqueous sample solutions, across a supported liquid membrane (SLM) consisting of 1-isopropyl-4-nitrobenzene impregnated in the walls of a hollow fiber, and into an acidified aqueous acceptor solution present inside the lumen of the hollow fiber with potential differences of 1-10 V applied over the SLM. Extractions from 1 ml standard solutions prepared in 10 mM HCl for 5 min and with a potential of 10 V demonstrated analyte recoveries of 50-93% in 25 l of 10 mM HCl as acceptor solution. This corresponds to enrichment factors of 20-37. Similar results were obtained with a common 9 V battery as power supply. Recoveries from low-voltage EME on human plasma, urine, and breast milk diluted with acetate buffer (pH 4) demonstrated recoveries in the range of 37-55% after 5 min of extraction. Excellent selectivity was demonstrated as no interfering peaks were detected. Standard curves in the range of 0.0625-0.625 g/ml demonstrated correlation coefficients of 0.994-0.999. Extraction recoveries from human plasma, urine or breast milk were not found to be sensitive towards individual variations. The results show that low-voltage EME has a future potential as a simple, selective, and time-efficient sample preparation technique of biological fluids.
Pulsed electromembrane extraction: A new concept of electrically enhanced extraction
In the present work, pulsed electromembrane extraction (PEME) is introduced for the first time as an efficient and inexpensive method for the extraction of ionizable compounds from different matrices. The setup proposed for electromembrane extraction (EME) provides a very stable system and satisfactory repeatability (RSDs < 4.4) in comparison with existing methods. In this paper, PEME is conducted for the extraction of model analytes from biological fluids. The effective parameters such as extraction time, applied voltage and the duration of pulse and outage period are optimized using the experimental design. Preconcentration factors in the range of 100–140 and recoveries in the range of 95–108 were obtained in different biological matrices. The linear dynamic ranges of 5–200 ng mL−1 (with correlation coefficient higher than 0.9955) and limits of detection of 1.0 ng mL−1 were obtained for both of the drugs. The figures of merit of PEME were compared with the results from conventional EME, which proves the advantages of the proposed technique.► Pulsed electromembrane extraction (PEME) is introduced for the first time. ► Method was applied for the extraction of ionizable compounds from aqueous matrices. ► PEME solves the problems of EME for extraction of analytes from saline samples. ► The effective parameters were optimized using the experimental design. ► Preconcentration factors as large as >100 were obtained for biological samples.
Extraction of peptides from body fluids using supported liquid membranes
Biocybernetics and Biomedical Engineering
Sample pre-treatment is a very important step in many analytical procedures, especially when the analyte is presented in low concentration in complex sample matrices. In this paper, potential using of the supported liquid membrane (SLM) technique as a sample preparation step in order to isolate, pre-concentrate and separate small peptides and phosphono dipeptides from aqueous solutions and body fluids is discussed. An influence of various parameters including carrier type, donor and acceptor phase compositions, presence of salts and proteins in analysed samples on extraction efficiency and selectivity is presented. Additionally, comparison of SLM extraction efficiency from aqueous samples and body fluids is presented. Finally, a fully automated system consisted of SLM extraction coupled on-line with HPLC-UV for the analysis of selected peptides from blood plasma is shown.