Malgorzata Szultka

Past, Present, and Future of Solid Phase Extraction: A Review

Sample preparation of target compounds from biological, pharmaceutical, environmental, and food matrices is one of the most time-consuming steps in analytical procedures. Extraction techniques are dominant, especially those based on the processes running on the phase such as liquid-liquid and/or liquid-solid. Due to the reproducibility of data, precision, relatively low cost of the appropriate analysis, simplicity of the determination, and the possibility of direct combination of those techniques with other methods (both on-line and off-line), they have become the most widespread in routine determinations. Additionally, sample pretreatment procedures have to be more selective, cheap, quick, and environmentally friendly. Selectivity is obtained by using procedures based on immunoaffinity or molecular imprinting. Reduction of costs can be obtained by automation of the extraction procedures (automated SPE) or techniques like column-switching. Reducing at least the time for sample preparation is achieved by introducing miniaturization techniques (multi-well SPE). This review summarizes the current achievements and application of solid phase extraction (SPE). The main aim is to deal with the utilization of different types of sorbents for solid-phase extraction and emphasize the use of new synthesized sorbents as well as to bring together studies on a systematic approach to SPE method development.

Polypyrrole solid phase microextraction: A new approach to rapid sample preparation for the monitoring of antibiotic drugs.

Simple or even rapid bioanalytical methods are rare, since they generally involve complicated, time-consuming sample preparation from the biological matrices like LLE or SPE. SPME provides a promising approach to overcome these limitations. The full potential of this innovative technique for medical diagnostics, pharmacotherapy or biochemistry has not been tapped yet. In-house manufactured SPME probes with polypyrrole (PPy) coating were evaluated using three antibiotics of high clinical relevance - linezolid, daptomycin, and moxifloxacin - from PBS, plasma, and whole blood. The PPy coating was characterised by scanning electron microscopy. Influences of pH, inorganic salt, and blood anticoagulants were studied for optimum performance. Extraction yields were determined from stagnant media as well as re-circulating human blood using the heart-and-lung machine model system. The PPy-SPME fibres showed high extraction yields, particularly regarding linezolid. The reproducibility of the method was optimised to achieve RSDs of 9% or 17% and 7% for SPME from stagnant or re-circulating blood using fresh and re-used fibres, respectively. The PPy-SPME approach was demonstrated to meet the requirements of therapeutic monitoring of the drugs tested, even from re-circulating blood at physiological flow rates. SPME represents a rapid and simple dual-step procedure with potency to significantly reduce the effort and expenditure of complicated sample preparations in biomedical analysis.

New coated SPME fibers for extraction and fast HPLC determination of selected drugs in human blood.

Polythiophene (PTh) and polypyrrole (PPy) as sorbent phases for solid phase microextraction (SPME) were applied in order to extract the multi-resistant Staphylococcus aureus (MRSA) antibiotic drugs (linezolid and daptomycin) from whole blood followed by high performance liquid chromatography (HPLC) determination with UV detection. Relative standard deviations (RSDs) of in vitro and pseudo in vivo measurements performed in whole blood were in the range of 4.58-15.91% and 6.09-17.33% for linezolid and daptomycin, respectively. Determination coefficients (R(2)) were in range of 0.9884-0.9945 and 0.9807-0.9818 for linezolid and daptomycin, respectively. This study proved better adsorption capacity of PTh SPME coating compared to PPy coating for both, linezolid and daptomycin.

Development of novel molecularly imprinted solid-phase microextraction fibers and their application for the determination of antibiotic drugs in biological samples by SPME-LC/MSn

Novel molecularly imprinted polymer (MIP)-coated fibers for solid-phase microextraction (SPME) fibers were prepared by using linezolid as the template molecule. The characteristics and application of these fibers were investigated. The polypyrrole, polythiophene, and poly(3-methylthiophene) coatings were prepared in the electrochemical polymerization way. The molecularly imprinted SPME coatings display a high selectivity toward linezolid. Molecularly imprinted coatings showed a stable and reproducible response without any influence of interferents commonly existing in biological samples. High-performance liquid chromatography with spectroscopic UV and mass spectrometry (MS) detectors were used for the determination of selected antibiotic drugs (linezolid, daptomycin, amoxicillin). The isolation and preconcentration of selected antibiotic drugs from new types of biological samples (acellular and protein-free simulated body fluid) and human plasma samples were performed. The SPME MIP-coated fibers are suitable for the selective extraction of antibiotic drugs in biological samples.

Microextraction sample preparation techniques in biomedical analysis

Biologically active compounds are found in biological samples at relatively low concentration levels. The sample preparation of target compounds from biological, pharmaceutical, environmental, and food matrices is one of the most time-consuming steps in the analytical procedure. The microextraction techniques are dominant. Metabolomic studies also require application of proper analytical technique for the determination of endogenic metabolites present in biological matrix on trace concentration levels. Due to the reproducibility of data, precision, relatively low cost of the appropriate analysis, simplicity of the determination, and the possibility of direct combination of those techniques with other methods (combination types on-line and off-line), they have become the most widespread in routine determinations. Additionally, sample pretreatment procedures have to be more selective, cheap, quick, and environmentally friendly. This review summarizes the current achievements and applications of microextraction techniques. The main aim is to deal with the utilization of different types of sorbents for microextraction and emphasize the use of new synthesized sorbents as well as to bring together studies concerning the systematic approach to method development. This review is dedicated to the description of microextraction techniques and their application in biomedical analysis.

Fibers with polypyrrole and polythiophene phases for isolation and determination of adrenolytic drugs from human plasma by SPME-HPLC

In this study, polypyrrole (PPy) and polythiophene (PTh) SPME coatings and their ability to extract selected adrenolytic drugs with different physico-chemical properties from standard solutions and human plasma samples were evaluated. In measurements metoprolol, oxprenolol, mexiletine, propranolol, and propaphenon were investigated. The main parameters such as extraction time, desorption conditions and pH influence were examined. Inter-day precisions were in range 0.1-2.0%, 1.1-2.9%, 1.3-2.6%, 0.1-2.6% and 0.3-2.1% for metoprolol, oxprenolol, mexiletine, propranolol and propaphenon, respectively. Accuracies were less than 15%, which was evaluated by analyzing preparation samples of five replicates. The method was successfully applied to human plasma samples spiked with selected adrenolytic drugs. The method was linear in the concentration range from 1 to 10microg/ml for all of studied adrenolytic drugs using human plasma samples. The PTh-SPME coating displayed higher extraction efficiency towards the target analytes in comparison to PPy-SPME. The reproducibility of the extraction using polypyrrole and polythiophene fibers was confirmed by variation coefficients lower than 8% and 3%, respectively.

Simultaneous determination of selected chemotherapeutics in human whole blood by molecularly imprinted polymers coated solid phase microextraction fibers and liquid chromatography-tandem mass spectrometry.

Development and validation of novel, general liquid chromatography-tandem mass spectrometry (LC-MS/MS) method for the simultaneous determination of amoxicillin (AMOX), cefatoxime (CEF), ciprofloxacin (CIP), daptomycin (DAPTO), fluconazole (FLU), gentamicin (GEN), clindamycin (KLI), linezolid (LIN), metronidazole (MET), moxifloxacin (MOXI) in human whole blood are described. Samples were prepared on solid phase microextraction way with the use of polymeric sorption coatings with molecular imprints and analyzed using a gradient separation over an ACE C18-column (4.6mm×150mm, 3μm) with isocratic elution. Positive electrospray ionization was employed as the ionization source. The mobile phase consisted of acetonitrile-water (0.1% formic acid or 5mM ammonium acetate) at a flow 0.4ml/min. The chromatographic run time was kept less than 9min. The intra- and inter-day relative standard deviation across three validation runs over the entire concentration range was less than 7.3%, while the accuracy was within ±8.4%. The mean recovery of all the analytes ranged from 65.0 to 83.0%. This method was successfully applied to clinical samples from patients with clinically diagnosed bacterial infections process.

A new approach for antibiotic drugs determination in human plasma by liquid chromatography–mass spectrometry

Sensitive and selective analytical procedures based on high performance liquid chromatography with mass spectrometric detection were developed for the determination of linezolid (LIN) and amoxicillin (AMOX) in human plasma samples. Samples were prepared by applying protein precipitation (PP), solid phase extraction (SPE), and microextraction in packed syringe (MEPS). The analytical separation was carried out using reversed phase liquid chromatography in isocratic mode. All analytes were monitored by mass spectrometry (MS) detection in the product ion mode and the method was validated covering the corresponding therapeutic range of 1-30 μg/mL and 1-50 μg/mL for LIN and AMOX respectively. The assay was linear over AMOX and LIN concentration ranges. The method provided good validation data: accuracy (102.9% (LIN), 100.9% (AMOX)), limit of detection (0.1407 ng/mL (LIN); 0.1341 ng/mL (AMOX); quantification (0.3814 ng/mL (LIN), 0.4249 ng/mL (AMOX)) and acceptable stability within 24h in the auto-sampler. Three different methods were compared as regards precision, accuracy, recovery and matrix effects. The proposed methods offer a fast and simple way to determine selected antibiotic drugs in human plasma that could be applied in pharmacokinetic studies.

A new way of solid-phase microextraction fibers preparation for selected antibiotic drug determination by HPLC–MS

The polypyrrole (PPy) and polythiophene (PTh) solid phase microextraction (SPME) coatings were obtained with the use of the electropolymerisation and linear sweep voltammetry. Such fibers were modified by an ozone treatment in a gaseous phase in the concentration of 2.1 ± 0.2 × 10(-5) mol dm(-3). Both kinds of fibers were applied in the microextraction of linezolid from standard solutions to compare the extraction efficiencies displayed by these sorption phases. In these investigations a better adsorption capacity was obtained for polypyrrole fibers and hence only these kinds of fibers were utilized in the measurements from human plasma. In all measurements the concentrations of the drugs were in the range from 1 to 20 μg ml(-1) (standard solutions) and 1 to 15 μg ml(-1) (human plasma). Before the measurements, an optimization of the desorption solution experiments was performed. The correlation coefficients (R) obtained in the standard solution and human plasma were in the range from 0.8399 to 0.9970. The relative standard deviations (RSDs) were in the range of 0.1-7.6%.

Pharmacokinetic study of amoxicillin in human plasma by solid-phase microextraction followed by high-performance liquid chromatography-triple quadrupole mass spectrometry.

Sensitive and selective analytical procedures based on high-performance liquid chromatography with mass spectrometric detection were developed for the determination of amoxicillin in human plasma samples. Samples were prepared by applying in-house manufactured molecularly imprinted solid-phase microextraction probes. The detection of target compounds was performed in multiple reaction monitoring mode. The multiple reaction monitoring detection was operated in the positive electrospray ionization mode using the transitions of m/z 366 ([M + H](+) ) → 349 for amoxicillin and m/z 390 ([M + H](+) ) → 372 for gemifloxacin. The method was validated with precision within 15% relative standard deviation and accuracy within 15% relative error. The method was successfully applied to study of the pharmacokinetics of amoxicillin in human plasma after oral administration of amoxicillin.