This work extends the present working range of isotachophoresis (ITP) with electrospray-ionization mass-spectrometric (ESI-MS) detection and describes for the first time a functional cationic electrolyte system for analyses at medium-alkaline pH. So far no ITP-MS application was published on the analysis of medium strong bases although there is a broad spectrum of potential analytes like biogenic amines, alkaloids or drugs, where this technique promises interesting gains in both sensitivity and specificity. The presented results include a selection of suitable sufficiently volatile ESI-compatible system components, discussion of factors affecting system properties, and recommendations for functional ITP electrolyte systems. Theoretical conclusions based on calculations and computer simulations are confirmed by experiments with a model mixture of beta-blockers. Practical applicability of the method is demonstrated on the example of analysis of sotalol in dried blood spots where direct injection of aqueous extract, ITP stacking and MS detection provide a fast, simple and sensitive technique with limits of quantitation on the sub-nM level.
This review brings a survey of studies on analytical ITP published since 2016 until the first quarter of 2018 and includes chapters about theory and principles, instrumentation and techniques, and analytical applications of ITP. It shows the position of analytical ITP among contemporary separation techniques, where particularly its unique concentrating capabilities keep the interest to include it into novel high-sensitivity analytical procedures. The reviewed papers are considered according to their nature, techniques used, and instrumentation employed. The significance of electrolyte system composition is emphasized by providing explicit values where possible.
- MeSH
- biologické markery analýza MeSH
- elektroforéza kapilární * MeSH
- izotachoforéza * MeSH
- lidé MeSH
- myši MeSH
- zvířata MeSH
- Check Tag
- lidé MeSH
- myši MeSH
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
- přehledy MeSH
Electrophoretic focusing on inverse electromigration dispersion (EMD) gradient is a new analytical technique based on a unique separation principle where weak non-amphoteric ionogenic species are focused, separated and transported to the detector by an EMD profile of suitable properties. The present work extends the theoretical description of this method by introducing the concept of resolution and deriving the fundamental equation expressing resolution as function of basic system parameters. The results indicate that at constant current operation, resolution is proportional to the square root of time. For variable current regimes (e.g. constant voltage), the time variable is replaced by the product of electric current and passed electric charge. Computer simulations for a model pair of substances support the validity of the presented theory and confirm the theoretical conclusion that resolution can be increased by allowing longer electromigration of the gradient in terms of time or passed charge. The experimental example shown comprises an anionic electrolyte system based on maleic acid and 2,6-lutidine, combined with ESI-MS detection and operated in the reverse mode due to strong electroosmotic flow and ESI suction. The practical implementation of the proposed methodology is done by application of negative pressure at the inlet vial, resulting in very substantial resolution enhancement and baseline separation of otherwise unresolved substances. The performance and high sensitivity of the developed technique is demonstrated on the example of simultaneous analysis of four sulfonamides and three dichlorophenols in waters with limits of detection on the 1 nM level.
- MeSH
- chlorfenoly analýza MeSH
- elektroforéza kapilární MeSH
- elektrolyty chemie MeSH
- hmotnostní spektrometrie s elektrosprejovou ionizací * MeSH
- limita detekce MeSH
- maleáty chemie MeSH
- pitná voda analýza MeSH
- pyridiny chemie MeSH
- sulfonamidy analýza MeSH
- tlak MeSH
- Publikační typ
- časopisecké články MeSH
This review brings a survey of papers on analytical ITP published since 2014 until the first quarter of 2016. The 50th anniversary of ITP as a modern analytical method offers the opportunity to present a brief view on its beginnings and to discuss the present state of the art from the viewpoint of the history of its development. Reviewed papers from the field of theory and principles confirm the continuing importance of computer simulations in the discovery of new and unexpected phenomena. The strongly developing field of instrumentation and techniques shows novel channel methodologies including use of porous media and new on-chip assays, where ITP is often included in a preseparative or even preparative function. A number of new analytical applications are reported, with ITP appearing almost exclusively in combination with other principles and methods.
- MeSH
- anorganické látky analýza MeSH
- elektroforéza kapilární * přístrojové vybavení metody MeSH
- izotachoforéza * přístrojové vybavení metody MeSH
- mikročipové analytické postupy MeSH
- nanočástice analýza MeSH
- organické látky analýza MeSH
- počítačová simulace MeSH
- povrchové vlastnosti MeSH
- Publikační typ
- časopisecké články MeSH
- přehledy MeSH
Capillary isotachophoresis (ITP) is an electrophoretic technique offering high sensitivity due to permanent stacking of the migrating analytes. Its combination with electrospray-ionization mass-spectrometric (ESI-MS) detection is limited by the narrow spectrum of ESI-compatible components but can be compensated by experienced system architecture. This work describes a methodology for sensitive analysis of hydroxyderivatives of s-triazine herbicides, based on implementation of the concepts of moving-boundary isotachophoresis and of H+ as essential terminating component into cationic ITP with ESI-MS detection. Theoretical description of such kind of system is given and equations for zone-related boundary mobilities are derived, resulting in a much more general definition of the effective mobility of the terminating H+ zone than used so far. Explicit equations allowing direct calculation for selected simple systems are derived. The presented theory allows prediction of stacking properties of particular systems and easy selection of suitable electrolyte setups. A simple ESI-compatible system composed of acetic acid and ammonium with H+ and ammonium as a mixed terminator was selected for the analysis of 2-hydroxyatrazine and 2-hydroxyterbutylazine, degradation products of s-triazine herbicides. The proposed method was tested with direct injection without any sample pretreatment and provided excellent linearity and high sensitivity with limits of detection below 100ng/L (0.5nM). Example analyses of unspiked and spiked drinking and river water are shown.
- MeSH
- atrazin analogy a deriváty analýza chemie MeSH
- elektrolyty chemie MeSH
- herbicidy analýza chemie MeSH
- hmotnostní spektrometrie s elektrosprejovou ionizací * MeSH
- izotachoforéza * MeSH
- látky znečišťující životní prostředí analýza MeSH
- sladká voda chemie MeSH
- voda chemie MeSH
- Publikační typ
- časopisecké články MeSH
This paper brings a survey of papers on analytical capillary ITP published since 2012 until the first quarter of 2014. These papers are ranged according to their nature, the techniques used, and the instrumentation employed. The sequence of the related chapter titles is as follows: Theory and simulations, techniques and instrumentation, single-column and column-switching applications of ITP, ITP in microfluidic systems, on-line ITP-CZE and transient ITP (tITP) techniques and applications. The review shows the position of analytical capillary ITP among contemporary separation techniques and implies the potential future trends.
- MeSH
- elektroforéza kapilární přístrojové vybavení metody MeSH
- izotachoforéza přístrojové vybavení metody MeSH
- lidé MeSH
- mikrofluidní analytické techniky přístrojové vybavení metody MeSH
- zvířata MeSH
- Check Tag
- lidé MeSH
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
- přehledy MeSH
This contribution is a methodological review of the publications about the topic from the last 2 years. Therefore, it is primarily organized according to the methods and procedures used in surveyed papers and the origin and type of sample and specification of analytes form the secondary structure. The introductory part about navigation in the architecture of stacking brings a brief characterization of the various stacking methods, with the description of mutual links to each other and important differences among them. The main body of the article brings a survey of publications organized according to main principles of stacking and then according to the origin and type of the sample. Provided that the paper cited gave explicitly the relevant data, information about the BGE(s) used, procedure, detector employed, and reached LOD and/or concentration effect is given. The papers where the procedure used is a combination of diverse fragments and parts of various stacking techniques are mentioned in a special section on combined techniques. The concluding remarks in the final part of the review evaluate present state of art and the trends of sample stacking in CE.
- MeSH
- analýza moči přístrojové vybavení metody MeSH
- analýza potravin přístrojové vybavení metody MeSH
- elektroforéza kapilární přístrojové vybavení metody MeSH
- hematologické testy přístrojové vybavení metody MeSH
- koncentrace vodíkových iontů MeSH
- lidé MeSH
- monitorování životního prostředí přístrojové vybavení metody MeSH
- voda analýza MeSH
- zvířata MeSH
- Check Tag
- lidé MeSH
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
- přehledy MeSH
The subject of this work is the definition of a simple model based on general ITP theory that allows describing and predicting the behavior of ITP systems compatible with ESI-MS detection. The model is exemplified by anionic ITP of weak acids that represent an interesting potential application field of ITP-ESI-MS. Suitable ESI-compatible electrolyte systems of very simple composition are proposed including a special free-acid ITP arrangement. The properties of these systems are discussed using illustrative diagrams of their stacking windows. The use of anionic ITP-ESI-MS in negative-ion ESI mode is reported for the first time and its suitability for sensitive trace analysis is demonstrated. The presented ITP-ESI-MS application example comprises a free-acid ITP system formed of formic and propionic acids and direct injection analysis of ibuprofen and diclofenac in waters with quantitation limits of the order 10(-10) M.
- MeSH
- anionty chemie MeSH
- antiflogistika nesteroidní analýza MeSH
- diklofenak analýza MeSH
- elektroforéza kapilární MeSH
- elektrolyty chemie MeSH
- hmotnostní spektrometrie s elektrosprejovou ionizací metody MeSH
- ibuprofen analýza MeSH
- izotachoforéza metody MeSH
- kyseliny chemie MeSH
- limita detekce MeSH
- neopioidní analgetika analýza MeSH
- pitná voda analýza MeSH
- řeky chemie MeSH
- Publikační typ
- časopisecké články MeSH
- hodnotící studie MeSH
- práce podpořená grantem MeSH
In this contribution we present an innovative way to easy, fast, and highly sensitive analyses by CE with ESI-MS detection. The new method is designed to be applied to ESI-compatible electrolytes (e.g. ammonium acetate) and offers advanced tuning of selectivity conditions within a wide range of analyte mobilities. We use a full capillary ITP format to provide powerful on-line analyte stacking at the ITP boundary all the way to detection and introduce the model of extended ITP where a controlled concentration of the leading ion is added to the terminating zone. Such systems preserve all properties of an ITP system and the velocity of the stacking ITP boundary can be tuned by the composition of both the leading and terminating zone. In this way, the system properties can be controlled flexibly and the mobility window of stacked analytes can be tailored to actual needs. The presented theory and the newly defined concept of zone-related boundary mobility allow easy assessment of system selectivity using simple diagrams. We demonstrate the model and its potential on the example of simple acidic cationic systems composed of only two substances (ammonium and acetate) including the example of thiabendazole analysis with a detection limit of 10(-10) M (20 ng/L) and its determination in orange juice by direct sampling after filtration, selective stacking by a tuned extended ITP system, and ESI-MS detection.
- MeSH
- acetáty chemie MeSH
- elektroforéza kapilární metody MeSH
- elektrolyty chemie MeSH
- hmotnostní spektrometrie s elektrosprejovou ionizací metody MeSH
- izotachoforéza metody MeSH
- kationty analýza chemie MeSH
- limita detekce MeSH
- nápoje analýza MeSH
- pomerančovník čínský chemie MeSH
- rezidua pesticidů analýza chemie MeSH
- thiabendazol analýza chemie MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
This review brings a survey of the literature on analytical isotachophoresis (ITP) from the years 2010-2012. It confirms the fact that ITP alone is not used for analyses frequently but that its online combinations with other methods are of paramount importance. This review shows that the inherent features of the technique and first of all its concentrating ability are still unique for reaching high sensitivity and efficient sample cleanup in analytical applications. The part devoted to theory is mostly represented by computer simulations and confirms the power and significance of this approach. The section oriented at instrumentation and techniques shows the advantages of ITP in column combinations and microchip techniques. The chapter reviewing the applications is categorized according to the techniques applied, viz., column switching, on line ITP-CZE and on-chip analyses. The final part of the review is devoted to the nearly omnipresent electrophoresis principle of transient isotachophoresis, and to the advantages that it may offer for detection and sampling. In all parts, the significance of the operational conditions is also considered and where possible, the electrolyte system is explicitly presented.
