By Arman Aziziyan Supervisor Professor. Parcheh baf

1. In the name of GOD Application of Ionic liquids in analytical chemistry By Arman Aziziyan Supervisor Professor. Parcheh baf

2. content • Definition • History • Principle of ionic liquid • Advantage • Limitation • the applications of ILs in analytical chemistry • Extractions • Gas chromatography • Liquid chromatography (LC) • Capillary electrophoresis • Mass spectrometry (MS) • Electrochemistry • Sensors • Conclusion

3. Definition • The term “ionic liquid” (IL) is currently used to describe a broad class of salts which have appreciable liquid ranges.(ILs melt at or below 100 ◦C) • Room temperature Ionic liquids (RTIL) are salts which are already liquid below room temperature Joan F. Brennecke, Edward J. Maginn, AIChE Journal, Vol. 47, 2001, p. 2384-2389

4. History • 1888 Gabriel and Weiner found ethanolammonium nitrate (m.p. 52–55 ◦C) • 1914 The “first” RTIL ethylammonium nitrate [EtNH3][NO3] with melting point12 ◦C • 1948 Development of IL with chloroaluminate ions by Hurley and Wier at the Rice Institute in Texas • 1982 reported by Wilkes , A new class of RTILs that consist of dialkylimidazolium chloroaluminate • 1992 Development of air- and water-stable imidazolium based ILs by Wilkes et al. • The number of publications based on ionic liquids raised from 14 in 1990 to over 8000 in 2010 Ionic liquid related Publications vs. year Captain (Dr.) John S. Wilkes at the U.S. Air Force Academy in1979 G.I.T laboratory journal Europe issue

5. Principle of ionic liquid • Ionic liquids are composed entirely of ions. • ILs may behave quite differently from common molecular liquids when used as solvents.

6. Principle of ionic liquid • Most RTILs have organic cations. • Anions could be inorganic, and more and more current RTILs consist of organic anions. Ping Sun, Daniel W. Armstrong, Ionic liquids in analytical chemistry,Analytica Chimica Acta Journal,

7. Advantage • wide liquid ranges • wide range of viscosities • Very low vapor pressure • Non-flammable substance • good thermal stabilities • High mechanically stable • electrolytic conductivity • Low toxicity • Non-volatility • adjustable miscibility • ability to be reutilized P.Wasserscheid & T.Welton, Ionic Liquids in Synthesis, Volume 1, 2008 WILEY-VCH

8. Limitation systemic and mechanistic understandings of IL properties are not adequate Toxicity and long-term stability of ILs can vary widely Some ILs are relatively impure

9. the applications of ILs in analytical chemistry divided into eight sections : • Extractions • gas chromatography (GC) • liquid chromatography (LC) • capillary electrophoresis (CE) • mass spectrometry (MS) • Electrochemistry • Sensors

10. 1)Extractions Sr2+ Ag+ • Liquid–liquid extraction La3+ and divalent metal ions (Cu2+, Mn2+, Co2+) gold nanoparticles and nanorods aromatic aliphatic hydrocarbons Organic acids Phenols amines proteins DNA [6] S. Dai, Y.H. Ju, C.E. Barnes, J. Chem. Soc (1999) [7] K. Shimojo, M. Goto, Anal. Chem. (2004) [8]&[9] & [10]&[11]Ping Sun, Daniel W. Armstrong, Ionic liquids in analytical chemistry,Analytica Chimica Acta Journal,

11. Extractions • Jiang and co-workers are among the first who applied ILs as extraction solvents in LPME b) Liquid phase microextraction • analyzed chlorobenzenes in water samples • analysis of some representative pollutants in water samples • coupled with HPLC was applied to detect insecticides and polycyclic aromatic hydrocarbons in water • using 1-hexylpyridinium PF6 as an extractant solvent was developed to preconcentrate zinc in water and milk samples • For preconcentrate and measure organic and inorganic compounds in real samples L. Vidal, E. Psillakis, C.E. Domini, N. Grane, F. Marken, A. Canals, Anal. Chim.Acta(2007) Ping Sun, Daniel W. Armstrong, Ionic liquids in analytical chemistry,Analytica Chimica Acta Journal,

12. Extractions c) Solid-phase microextraction • quantitatively analyze benzene, toluene, ethylbenzene, xylene in paints • Polymeric imidazolium-based IL coatings were synthesized and applied to extract esters Polymeric coating

13. 2) Gas chromatography • In the first time using molten salts in GC started in the 1950 and prepared GC stationary phases using molten salts.

14. Gas chromatography monomer GC capillary was coated by polymerization of ILS as stationary phase. Column temperature: 100 °C hold 2 min, 15 min to 260 °C. Cross-linker Separation of fatty acid methyl esters (C6-C24) Armstrong, D.W; Anderson, J. Analytical Chemistry, 2005

15. 3) Liquid chromatography (LC) Most current HPLC and TLC stationary phases use silica gel as the solid support. the silica surface has residual acidic silanol groups, which have deleterious effects on separations. For example, tailing. Kaliszan first reported in 2004 that IL additives in the mobile phase suppressed free silanol effects on the retention of basic drug compounds in TLC. Ping Sun, Daniel W. Armstrong, Ionic liquids in analytical chemistry,Analytica Chimica Acta Journal, SOMENATH MITRA , Sample Preparation Techniques in Analytical Chemistry,2003, A JOHN WILEY & SONS

16. Liquid chromatography (LC) • ILs was mixed with another solvent of low viscosity and used as the mobile phase. • adding ILs to HPLC mobile phases is to shield the acidic silica surface, in order to improve the peak shape and reduce the peak broadening • using IL additives to suppress the silanol effect when separating basic drug molecules LC mobile phase additives Application ILs in LC • separated anions, amines, and nucleotides • exhibited both a strong anion exchange character and a reversed phase interaction LC stationary phases Ping Sun, Daniel W. Armstrong, Ionic liquids in analytical chemistry,Analytica Chimica Acta Journal H. Qiu, S. Jiang, X. Liu, L. Zhao, J. Chromatogr. A .2006.

17. 4) Capillary electrophoresis Application of Ils in CE the IL-coated capillary can increase recovery The dynamic coating of ILs could also reverse the EOF and improve separations demonstrates the effects of the alkyl group on the imidazolium cation and the anion nature on the separation of polyphenols applications of ILs as dynamic coating materials to separate acidic and basic proteins , inorganic and small organic anions In Non-aqueous CE ILs possess some attractive properties over conventional organic solvent modifiers, such as good electrical conductivity • Mechanism of polyphenols’ separation using 1-alkyl-3 methylimidazolium-based ionic liquids • Separation of polyphenols using (A) 1-ethyl-3- methylimidazolium tetrafluoroborate, (B) 1-butyl-3-methylimidazolium tetrafluoroborate, and (C) 1-ethyl-3-methylimidazolium hexafluorophosphate Warner and coworkers used polymeric surfactants with ILs as modifiers in MCE to separate both achiral and chiral compounds Ping Sun, Daniel W. Armstrong, Ionic liquids in analytical chemistry,Analytica Chimica Acta Journal A. Berthod, S. Carda-Broch,Uses of Ionic Liquids in Analytical Chemistry, CNRS, Université de Lyon2003

18. 5) Mass spectrometry (MS) MALDI matrices • The role of the matrix is: • (i) to absorb strongly the laser UV light and convert it in enough heat so that the solute will be vaporized • (ii) to ionize the solute so it can fly if an electrostatic field is applied • matrix properties: 1) absorption at the laser wavelength 2) capabilities of dissolving or cocrystalizing with the sample 3) low volatility 4) suppressing analyte decompositions 5) promoting the ionization of analytes A UV absorbing liquid that has a low vapor pressure • Ideal matrix: Dissolves the sample and can promote sample ionization (proton transfer) http://www.chm.bris.ac.uk/ms/theory/maldi-ionisation.html Ping Sun, Daniel W. Armstrong, Ionic liquids in analytical chemistry,Analytica Chimica Acta Journal A. Berthod, S. Carda-Broch,Uses of Ionic Liquids in Analytical Chemistry, CNRS, Université de Lyon2003

19. Mass spectrometry (MS) Armstrong first developed effective ILs as MALDI matrixes • properties of Ils that make them suitable for working as MALDI matrixes: • 1) low volatility • 2) wide solubility with various types of compounds As a good IL matrix, the cations must have a high pKa (≥11) and proton affinity (>930 kJ mol−1) • also utilized ILs as MALDI matrixes to detect various types of molecules, including: • peptides and proteins , DNA ,saccharides , and synthetic polymers , and compounds of low molecular weight It was reported that the signal reproducibility was significantly improved using IL matrixes Ping Sun, Daniel W. Armstrong, Ionic liquids in analytical chemistry,Analytica Chimica Acta Journal Daniel W. Armstrong, Li-Kang Zhang, Lingfeng He and Michael L. Gross,Iowa State University , Analytical Chemistry. 2001

20. 6) Electrochemistry • Electrochemistry basically needs two materials: • electro conductive materials • ion conductive materials • Ionic liquids open the possibility of improving ion conductive materials. properties of Ils that make them capable to use electrochemistry • nonflammable • high ionic conductivity • low volatility Some unique feature of Ils in electrochemistry : the electrochemical potential window of ILs is 4–5 V ILs themselves can be electroactive Electrochemistry is a useful technique to study IL-aqueous interfacial properties, which are useful in investigations of extractions using ILs Some materials are not soluble in aqueous and organic solvents , The use of ILs could solve some practical problems during electrochemical studies because this materials could solved by using of IL solvent and reproducible results were obtained Hiroyuki Ohno ,Electrochemical Aspects of Ionic Liquids , Japan , JOHN WILEY & SONS, INC., PUBLICATION Ping Sun, Daniel W. Armstrong, Ionic liquids in analytical chemistry,Analytica Chimica Acta Journal

21. 7)Sensors The RTIL functioned as a nonvolatile electrolyte in the gas sensor and eliminated the use of membranes, Electrochemistry-based sensors able to work in extreme conditions The use of Ils minimized the absorbed water slow response times and irreversible redox reactions optical CO2 sensor using the RTIL ([MBIM][BF4] or [MBIM][Br]) Optical sensors A hybrid electrochemical-colorimetric sensing platform for detecting explosives was developed When analytes were dissolved in an IL, the viscosity of this IL changed rapidly, which gave a frequency shift of the QCM device Sensors based on quartz crystal microbalance as sensor coating materials for organic vapor sensors using QCM developed miniaturized gas sensor arrays using a multichannel monolithic QCM Stochastic sensors supporting electrolytes for nanopore stochastic sensors the translocation velocities of various DNA homo- and copolymers through protein pores in the DNA sensor

22. Sensors Optical sensors Electrochemistry-based sensors

23. Conclusion • The application of Ionic liquids in analytical chemistry is growing: • Chromatography • MALDI • Electrochemistry • Extraction • Commercial availability of ILs will increase • Possible new applications: • Nano science (charged nano-particles, hydrophobic nano-pores) • Laser Induced Back Ablation • New particles: (drug delivery, liquid aerosol)

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