Solid-phase extraction Dotaz Zobrazit nápovědu
Extrakce na pevnou fázi je rychlý, jednoduchý, účinný a flexibilní způsob přípravy vzorků k vlastníanalýze, využitelný v mnoha oblastech analýzy (farmacie, biochemie, potravinářství, životní prostředí aj.). Výhodná je možnost použití v on-line systémech a v automatických systémech. Velmiširoká ikála nabízených typů sorbentů a využití jejich kombinace tak z extrakce na pevnou fázivytváří účinný způsob k izolaci a prekoncentraci analytu ze složité matrice vzorku.
Extraction on the solid phase is a rapid, simple, effective, and flexible method of preparation ofsamples for the analysis proper and it can be used in many areas of analysis (pharmacy, biochemistry, food industry, environmental examination, etc.). Possible use in on-line and automatic systemsis also advantageous. A very wide scale of proposed sorbents and the use of their combinations thusmake extraction on the solid phase an effective method for the isolation and preconcentration of theanalyte from the complex matrix of the sample.
The aim of the work was to synthesize a molecularly imprinted material for the selective solid-phase extraction (SPE) of β-N-methylamino-L-alanine (L-2-amino-3-methylpropionic acid; BMAA) from cyanobacterial extracts. BMAA and its structural analogs that can be used as template are small, polar and hydrophilic molecules. These molecules are poorly soluble in organic solvents that are commonly used for the synthesis of acrylic-based polymers. Therefore, a sol gel approach was chosen to carry out the synthesis and the resulting sorbents were evaluated with different extraction procedures in order to determine their ability to selectively retain BMAA. The presence of imprinted cavities in the sorbent was demonstrated by comparing elution profiles obtained by using molecularly imprinted silica (MIS) and non-imprinted silica (NIS) as a control. The molecularly imprinted solid-phase extraction (MISPE) procedure was first developed in a pure medium (acetonitrile) and further optimized for the treatment of cyanobacterial samples. It was characterized by high elution recoveries (89% and 77% respectively in pure and in real media).The repeatability of the extraction procedure in pure medium, in real medium and the reproducibility of MIS synthesis all expressed as RSD values of extraction recovery of BMAA were equal to 3%, 12% and 5%, respectively. A MIS capacity of 0.34 µmol/g was measured. The matrix effects, which affected the quantification of BMAA when employing a mixed mode sorbent, were completely removed by adding a clean-up step of the mixed-mode sorbent extract on the MIS.
Until now, analysis of Ofloxacin in human blood plasma using solid-phase extraction (SPE) by HPLC UV detector has not been reported. This study aims to determine the validity of analytical methods in Ofloxacin study in human blood plasma (in vitro) using an HPLC SPE UV detector. Plasma samples were extracted by SPE. Analytes were analyzed using a C18 column (octadecylsilane) 250x4.6 mm, particle size 10 μm, mobile phase 85,5:14,5 v v 0.025 M phosphate buffer (pH 2.2) and acetonitrile with a flow rate of 2 ml/min, detection performed at 294 nm with the internal standard ciprofloxacin. Validated analytical method was based on the parameters: selectivity, accuracy, precision, repeatability, linearity, LOD, LOQ, and the suitability of the system. Validation analysis showed selectivity test Rs>1.5, test repeatability with CV(%) <10%, linearity was obtained in the range of 0.1 to 6 µg/ml with correlation coefficient (r) from 0.9998 to 0.9999. Based on the area ratio of peak height and a segment of the chromatogram obtained LOD values 0.023 and 0.024 µg/ml, LOQ value of 0.076 and 0.080 tg/ml, percent accuracy from 94.32 to 100.45% and 97.68 to 101.63%, and precision CV (%) 0.31 to 0.85% and 0.84 to 1.08%. System suitability test results on the retention time, area ratio, and high ratios of peak chromatogram shows the CV(%) <10%. Can be concluded that the analytical methods used have validity in accordance with the requirements.
- MeSH
- antibakteriální látky izolace a purifikace MeSH
- ciprofloxacin * analýza izolace a purifikace krev MeSH
- extrakce na pevné fázi * metody přístrojové vybavení MeSH
- krevní plazma MeSH
- lidé MeSH
- ofloxacin * analýza izolace a purifikace krev MeSH
- vysokoúčinná kapalinová chromatografie * metody MeSH
- Check Tag
- lidé MeSH
Porous polymer monoliths have been used to develop an online solid-phase extraction with liquid chromatography method for determination of dopamine in urine as well as for a continuous monitoring of dopamine in flowing system. A polymerization mixture containing 4-vinylphenylboronic acid monomer has been used to prepare a trapping column based on specific ring formation reaction with dopamine cis-diol functionality. Additionally, a monolithic stationary phase with zwitterion functionality has been used to prepare capillary column for the separation of dopamine. Experimental conditions including molarity, pH, and flow rate of the loading buffer together with a valve switching time have been optimized to provide the highest recovery for dopamine. Experimental setup has been used to determine dopamine in a urine. By using both calibration curve and standard addition method, the dopamine level was determined to be 1.19 and 1.28 mg/L, respectively. Further, we have used experimental design to optimize coupling of two extraction monolithic loops to separation capillary column with monolithic phase for a comprehensive monitoring of dopamine. After multivariate analysis, sample loading flow-rate and a flow-rate of flushing buffer were selected as the most significant variables. Optimized experimental setup was applied to continuously monitor dopamine degradation.
- MeSH
- dopamin moč MeSH
- extrakce na pevné fázi * MeSH
- lidé MeSH
- polymerizace MeSH
- polymery MeSH
- vysokoúčinná kapalinová chromatografie * MeSH
- Check Tag
- lidé MeSH
- Publikační typ
- časopisecké články MeSH
A molecularly imprinted polymer (MIP) was synthesized and evaluated to selectively extract ephedrine from human plasma. The MIP synthesis was performed in chloroform with methacrylic acid as a functional monomer and the target alkaloid as a template molecule. The resulting MIP was applied to the selective extraction of ephedrine from a pure aqueous medium. A recovery about 74% was obtained using the MIP with only 7% on the nonimprinted polymer (NIP). A very straightforward selective SPE procedure was then successfully applied to the direct extraction of ephedrine from spiked human plasma with a high extraction recovery (68%) on the MIP with no recovery on the NIP. Moreover, the MIP was used for the selective extraction of catecholamine neurotransmitters, i.e. adrenaline and noradrenaline.
Zosyntetizovali sa polyméry s odtlačkami molekúl na extrakciu 1-metyl-2-piperidínoetylesterov 2-metoxyfenylkarbámovej kyseliny, ktorá sa použila ako templát. Pri syntéze sa použili funkčné monoméry akrylamid a kyselina metakrylová. Pripravené polyméry sa testovali ako sorbenty na extrakciu tuhou fázou (MISPE). Študovala sa ich kapacita a selektivita k derivátom 1-metyl-2-piperidínoetylesterov alkoxyfenylkarbámových kyselín, ktoré sú lokálne anestetiká. Zároveň rovnakou metódou sa pripravili polyméry bez použitia templátu, čím sa mohli zistiť nešpecifické interakcie medzi sorbentom a skúmanými látkami. Polymér pripravený pomocou metakrylovej kyseliny sa použil na predkoncentráciu 1-metyl-2-piperidínoetylesteru 2-metoxyfenylkarbámovej kyseliny z ľudskej plazmy, do ktorej sa pridala uvedená látka (1 µg v 1 ml plazmy).
Molecularly imprinted polymers for 1-methyl-2-piperidinoethylester of 2-methoxyphenylcarbamic acid (template) have been synthesised. Acrylamide and methacrylic acids, respectively, were used as the functional monomers. Imprinted polymers were used as the sorbents for solid-phase extraction (MISPE). The capacity and selectivity of prepared imprinted polymers were investigated with the use of some derivatives of 1-methyl-2-piperidinethylesters of alkoxyphenylcarbamic acids. The non-imprinted (blank) polymers were prepared by the same way without a template to study the non-specific interactions. The molecularly imprinted polymer prepared from methacrylic acid was used to preconcentrate 1-methyl-2-piperidinoethylester of 2-methoxyphenylcarbamic acid and its analogues from spiked human plasma (1 µg in 1 ml of plasma).
Seven solid phase sorbent materials with reversed-phase, mixed-mode interactions (ion-exchange and reversed-phase), and molecularly imprinted polymers (MIP), namely Oasis HLB, Oasis MAX, Oasis MCX, Bond Elute Plexa, Bond Elute Plexa PAX, Bond Elute Plexa PCX, and SupelMIP sorbents, were investigated. The present study was focused on the retention and elution of pharmaceutically active substances based on several analyte-sorbent interaction properties. Basic drugs, such as β-blockers (i.e., atenolol, pindolol, acebutolol, metoprolol, labetalol, and propranolol) were selected as the model compounds for this study. These compounds are frequently encountered in anti-doping tests. The extraction efficiencies of the individual sorbents were compared based on the recovery of known amounts of the targeted analytes in a metered elution volume (500 μL) in three separate elution fractions. The elution efficiency of the total amount of the target analytes on various sorbents was not appreciably influenced by the volume of eluent required for complete elution. Based on the small matrix effects and clear baseline, SupelMIP was the most suitable sorbent for urine analysis. The relative analyte recoveries of the SPE-HPLC procedure proved satisfactory for the range from 94% to 105%, with an RSD ranging from 2% to 4%. The regression equations for all of the targeted compounds exhibited excellent linearity (r(2) > 0.9991) over the range of 10 to 1000 ng mL(-1). The limits of detection and quantification for the selected β-blocker compounds in urine were in the ranges of 0.6 to 2.0 ng mL(-1) and 2.0 to 6.7 ng mL(-1), respectively.
- MeSH
- adsorpce MeSH
- beta blokátory izolace a purifikace moč MeSH
- extrakce na pevné fázi přístrojové vybavení metody MeSH
- lidé MeSH
- molekulový imprinting MeSH
- polymery chemická syntéza chemie MeSH
- Check Tag
- lidé MeSH
- Publikační typ
- časopisecké články MeSH
- hodnotící studie MeSH
- práce podpořená grantem MeSH
The efficiency of solid phase extraction (SPE) of DNA on polymer particles is limited by the features of the applied solid support, such as size, hydrophilicity, and functionality and their application in SPE also requires additional steps and compounds to finally obtain sufficient amount of high-quality DNA. The present study describes a preparation of sub-micrometer monodisperse poly(methacrylic acid-co-ethylene dimethacrylate) (PME) particles by precipitation polymerization. The effect of the ethylene dimethacrylate (EDMA) crosslinker concentration on morphology and particle size, which varied from 730 to 900 nm, was investigated. The particles with 5 and 15 wt% EDMA were selected for a study of SPE of plasmid DNA under various adsorption and elution conditions, followed by the enzymatic restriction of isolated DNA to verify a quality the nucleic acid. The particles with 15 wt% EDMA were suitable for the SPE because they retained better colloidal stability during the adsorption without additional induction of DNA conformational change. The quality of isolated DNA was finally verified by enzymatic restriction by restriction endonuclease EcoRI. Moreover, the developed method using PME particles was successfully utilized for DNA isolation from Escherichia coli lysate.
- MeSH
- DNA bakterií chemie izolace a purifikace MeSH
- DNA chemie izolace a purifikace MeSH
- extrakce na pevné fázi * metody MeSH
- hydrofobní a hydrofilní interakce MeSH
- koncentrace vodíkových iontů MeSH
- polymery chemie MeSH
- polymethylmethakrylát chemie MeSH
- velikost částic MeSH
- Publikační typ
- časopisecké články MeSH
