Microscale separations
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Miniaturization continues to be one of the leading trends in analytical chemistry and one that brings advantages that can be particularly beneficial in biochemical research. Use of a miniaturized scale enables efficient analysis in a short time and requires very small amounts of samples, solvents, and reagents. This can result in a remarkable decrease in costs of enzyme kinetics studies, especially when expensive or rare enzymes and/or substrates are involved. Free zone electrophoresis is without a doubt the most common microscale separation technique for capillary and on-chip enzyme assays. Progress and applications in this field are reviewed frequently whereas other modes of separation, although successfully applied, receive only marginal interest in such publications. This review summarizes applications of less common modes of separation in capillary or chip formats, namely micellar electrokinetic chromatography, liquid chromatography, gel electrophoresis, isoelectric focusing, and isotachophoresis. Because these techniques are based on separation mechanisms different from those of free zone electrophoresis, they can be, and have been, successfully used in cases where zone electrophoresis fails. Advantages and drawbacks of these alternative separation techniques are discussed, as also are the difficulties encountered most often and solutions proposed by different research groups.
- MeSH
- chromatografie micelární elektrokinetická kapilární metody MeSH
- elektroforéza kapilární metody MeSH
- enzymatické testy metody MeSH
- isoelektrická fokusace metody MeSH
- izotachoforéza metody MeSH
- kapilární elektrochromatografie metody MeSH
- kinetika MeSH
- lidé MeSH
- miniaturizace metody MeSH
- zvířata MeSH
- Check Tag
- lidé MeSH
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
- přehledy MeSH
Cytokinins (CKs) are pivotal plant hormones that have crucial roles in plant growth and development. However, their isolation and quantification are usually challenging because of their extremely low levels in plant tissues (pmol g-1 fresh weight). We have developed a simple microscale magnetic immunoaffinity-based method for selective one-step isolation of CKs from very small amounts of plant tissue (less than 0.1 mg fresh weight). The capacity of the immunosorbent and the effect of the complex plant matrix on the yield of the rapid one-step purification were tested using a wide range of CK concentrations. The total recovery range of the new microscale isolation procedure was found to be 30-80% depending on individual CKs. Immunoaffinity extraction using group-specific monoclonal CK antibodies immobilized onto magnetic microparticles was combined with a highly sensitive ultrafast mass spectrometry-based method with a detection limit close to one attomole. This combined approach allowed metabolic profiling of a wide range of naturally occurring CKs (bases, ribosides and N9 -glucosides) in 1.0-mm sections of the Arabidopsis thaliana root meristematic zone. The magnetic immunoaffinity separation method was shown to be a simple and extremely fast procedure requiring minimal amounts of plant tissue.
- MeSH
- elektroforéza kapilární metody využití MeSH
- počítačová simulace MeSH
- proteiny analýza MeSH
- teoretické modely MeSH
- Publikační typ
- kongresy MeSH
In this work, we have designed, constructed, and evaluated simple, inexpensive open-source data acquisition systems based on various analog-to-digital converter modules (ADS 1115, MCP 3424, LTC 2400, with resolution from 16 to 24-bit) and a miniature Arduino Nano TM microcontroller. The constructed data acquisition systems provide excellent performance and are comparable to a commercial, 24-bit device. We provide full schematics and corresponding source codes so that analytical chemists can easily construct any of the developed systems without extensive electronic or programming knowledge. The 24-bit LTC 2400 based device provided the best and comparable performance to a commercial, high-end 24-bit sigma to delta converter (ORCA 2800) at a fraction of cost (less than 50 USD compared to 870 USD for the commercial counterpart). The excellent performance was verified using a capillary electrophoresis system with contactless conductivity detection and separation of inorganic ions in clinical skin wipe and tap water samples.
- MeSH
- elektrická vodivost MeSH
- elektroforéza kapilární * MeSH
- ionty MeSH
- software * MeSH
- voda MeSH
- Publikační typ
- časopisecké články MeSH
The success of microfluidic immunocapture based on magnetic beads depends primarily on a sophisticated microscale separation system and on the quality of the magnetic immunosorbent. A microfluidic chip containing a magnetically stabilized fluidized bed (μMSFB), developed for the capture and on-chip amplification of bacteria, was recently described by Pereiro et al.. The present work shows the thorough development of anti-Salmonella magnetic immunosorbents with the optimal capture efficiency and selectivity. Based on the corresponding ISO standards, these parameters have to be high enough to capture even a few cells of bacteria in a proper aliquot of sample, e.g. milk. The selection of specific anti-Salmonella IgG molecules and the conditions for covalent bonding were the key steps in preparing an immunosorbent of the desired quality. The protocol for immunocapturing was first thoroughly optimized and studied in a batchwise arrangement, and then the carrier was integrated into the μMSFB chip. The combination of the unique design of the chip (guaranteeing the collision of cells with magnetic beads) with the advanced immunosorbent led to a Salmonella cell capture efficiency of up to 99%. These high values were achieved repeatedly even in samples of milk differing in fat content. The rate of nonspecific capture of Escherichia coli (i.e. the negative control) was only 2%.
- MeSH
- Escherichia coli izolace a purifikace MeSH
- imunoglobulin G chemie MeSH
- imunomagnetická separace přístrojové vybavení metody MeSH
- laboratoř na čipu MeSH
- mikrofluidní analytické techniky přístrojové vybavení metody MeSH
- mikrosféry MeSH
- mléko chemie MeSH
- Salmonella cytologie imunologie izolace a purifikace MeSH
- zvířata MeSH
- Check Tag
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
sv.
- MeSH
- elektroforéza MeSH
- klinická chemie metody MeSH
- Publikační typ
- periodika MeSH
- Konspekt
- Chemie. Mineralogické vědy
- NLK Obory
- chemie, klinická chemie
- chemie, klinická chemie
The review brings a comprehensive overview of recent developments and applications of high performance capillary and microchip electroseparation methods (zone electrophoresis, isotachophoresis, isoelectric focusing, affinity electrophoresis, electrokinetic chromatography, and electrochromatography) to analysis, microscale isolation, purification, and physicochemical and biochemical characterization of peptides in the years 2015, 2016, and ca. up to the middle of 2017. Advances in the investigation of electromigration properties of peptides and in the methodology of their analysis (sample preseparation, preconcentration and derivatization, adsorption suppression and EOF control, and detection) are described. New developments in particular CE and CEC methods are presented and several types of their applications to peptide analysis are reported: qualitative and quantitative analysis, determination in complex (bio)matrices, monitoring of chemical and enzymatical reactions and physical changes, amino acid, sequence and chiral analysis, and peptide mapping of proteins. Some micropreparative peptide separations are shown and capabilities of CE and CEC methods to provide important physicochemical characteristics of peptides are demonstrated.
- MeSH
- aminokyseliny chemie MeSH
- chemická frakcionace MeSH
- elektroforéza kapilární metody MeSH
- lidé MeSH
- mikročipová analýza metody MeSH
- peptidové mapování MeSH
- peptidy analýza izolace a purifikace MeSH
- stereoizomerie MeSH
- zvířata MeSH
- Check Tag
- lidé MeSH
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
- přehledy MeSH
The paper describes a novel control strategy for simultaneous manipulation of several microscale particles over a planar microelectrode array using dielectrophoresis. The approach is based on a combination of numerical nonlinear optimization, which gives a systematic computational procedure for finding the voltages applied to the individual electrodes, and exploitation of the intrinsic noise, which compensates for the loss of controllability when two identical particles are exposed to identical forces. Although interesting on its own, the proposed functionality can also be seen as a preliminary achievement in a quest for a technique for separation of two particles. The approach is tested experimentally with polystyrene beads (50 microns in diameter) immersed in deionized water on a flat microelectrode array with parallel electrodes. A digital camera and computer vision algorithm are used to measure the positions. Two distinguishing features of the proposed control strategy are that the range of motion is not limited to interelectrode gaps and that independent manipulation of several particles simultaneously is feasible even on a simple microelectrode array.
- MeSH
- algoritmy MeSH
- design vybavení MeSH
- elektrody MeSH
- elektroforéza metody MeSH
- hluk MeSH
- mikromanipulace přístrojové vybavení metody MeSH
- mikrosféry MeSH
- počítačové zpracování signálu přístrojové vybavení MeSH
- teoretické modely MeSH
- zpětná vazba * MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
... Ion Exchange Separation of Chromium Complexes 103 -- Ion Exchange Chromatography 103 Ligand Exchange ... ... Microscale Synthesis of Vaska’s Complex 1??1(??)[?(???5)?] ...
3rd ed. 272 s.
