| Reference | [1]. Langmuir. 2018 Apr 3;34(13):3797-3805. doi: 10.1021/acs.langmuir.7b04164. Epub 2018 Mar 20.<br />
Interaction of Hydrophobic Ionic Liquids with Lipids in Langmuir Monolayers.<br />
Gonçalves da Silva AMPS(1).<br />
Author information: (1)Centro de Química Estrutural, Instituto Superior Técnico , Universidade de Lisboa , 1049-001 Lisboa , Portugal.<br />
The interaction of two ionic liquids, trihexyl(tetradecyl)phosphonium bis(trifluoromethylsulfonyl)-imide and trihexyl(tetradecyl)phosphonium dicyanamide, [P6 6 6 14][Ntf2] and [P6 6 6 14]/[N(CN)2], with several long-chained lipids with a different net charge at the hydrophilic group, a cationic surfactant, dioctadecyldimethylammonium bromide (DODAB), a zwitterionic phospholipid (DPPC), an anionic phospholipid (DPPG), and the neutral stearic acid (SA), was investigated at the air-water interface using the Langmuir trough technique. The experimental surface pressure-area (π- A) isotherms obtained for selected compositions of each binary system reveal distinct interfacial behavior. The degree and the nature of the IL-lipid interaction strongly depend on the charge distribution in the lipid polar group. Miscibility, or immiscibility, at the monolayer was inferred from the comparison of the experimental π- A isotherm with the theoretical curve calculated for the corresponding ideal mixture based on the π- A isotherms of the pure components. Phase separation and partial miscibility occurred in IL/DODAB and IL/DPPC systems, respectively. In both the IL/DPPG and the IL/SA systems, a new catanionic complex was found. For the IL/SA system, the catanionic complex formation varies with the subphase pH.<br />
DOI: 10.1021/acs.langmuir.7b04164 PMID: 29518336<br />
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[2]. J Chromatogr A. 2020 May 24;1619:460969. doi: 10.1016/j.chroma.2020.460969. Epub 2020 Feb 13.<br />
Can the selectivity of phosphonium based ionic liquids be exploited as stationary phase for routine gas chromatography? A case study: The use of trihexyl(tetradecyl) phosphonium chloride in the flavor, fragrance and natural product fields.<br />
Cagliero C(1), Mazzucotelli M(2), Rubiolo P(2), Marengo A(2), Galli S(3), Anderson JL(4), Sgorbini B(2), Bicchi C(2).<br />
Author information: (1)Laboratory of Pharmaceutical Biology and Food Chemistry, Dipartimento di Scienza e Tecnologia del Farmaco, Via Pietro Giuria 9, 10125 Torino, Italy. Electronic address: [email protected]. (2)Laboratory of Pharmaceutical Biology and Food Chemistry, Dipartimento di Scienza e Tecnologia del Farmaco, Via Pietro Giuria 9, 10125 Torino, Italy. (3)MEGA S.r.l., Via Plinio, 29, 20025 Legnano, MI, Italy. (4)Department of Chemistry, Iowa State University, 50011 Ames, IA, USA.<br />
Room temperature ionic liquids (ILs) are well established stationary phases (SPs) for gas chromatography (GC) in several fields of applications because of their unique and tunable selectivity, low vapor pressure and volatility, high thermal stability (over 300 °C), and good chromatographic properties. This study is focused on an IL based on a phosphonium derivative (trihexyl(tetradecyl)phosphonium chloride, [P66614+] [Cl-]), previously shown to be suitable as a gas chromatographic SP because of its unique selectivity. In particular, it aims to establish the operative conditions to apply [P66614+][Cl-] to routine analysis of samples containing medium to high volatility analytes with different polarity, organic functional groups and chemical structure. In the first part, the study critically evaluates long term [P66614+][Cl-] column stability and maximum allowable operating temperatures (MAOT). The relatively low MAOT (210 °C) requires the adoption of a dedicated approach for analytes eluting above this temperature based on a suitable combination of efficiency and selectivity, and column characteristics (length, inner diameter and film thickness) and operative conditions. The performance of [P66614+][Cl-] as a GC SP have been validated through the Grob test, a model mixture of 41 compounds of different polarity, structure, and with different organic functional groups in the flavor and fragrance field, a standard mixture of 37 fatty acid methyl esters, some essential oils containing pairs or groups of compounds of different volatility critical to separate in particular peppermint, thyme, oregano, sandalwood and frankincense. The above approach has produced highly satisfactory separations with all of the samples investigated.<br />
DOI: 10.1016/j.chroma.2020.460969 PMID: 32089290 [Indexed for MEDLINE]<br />
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[3]. Phys Chem Chem Phys. 2021 Mar 18;23(10):6190-6203. doi: 10.1039/d0cp05845a.<br />
Transition anionic complex in trihexyl(tetradecyl)phosphonium-bis(oxalato)borate ionic liquid – revisited.<br />
Shimpi MR(1), Rohlmann P(2), Shah FU(1), Glavatskih S(3), Antzutkin ON(4).<br />
Author information: (1)Chemistry of Interfaces, Luleå University of Technology, SE-97 187, Luleå, Sweden. [email protected] [email protected]. (2)System and Component Design, KTH Royal Institute of Technology, SE-10 044 Stockholm, Sweden. (3)System and Component Design, KTH Royal Institute of Technology, SE-10 044 Stockholm, Sweden and School of Chemistry, University of New South Wales, UNSW Sydney NSW 2052, Australia and Department of Electromechanical, Systems and Metal Engineering, Ghent University, B-9052 Ghent, Belgium. (4)Chemistry of Interfaces, Luleå University of Technology, SE-97 187, Luleå, Sweden. [email protected] [email protected] and Department of Physics, Warwick University, CV4 7AL, Covertly, UK.<br />
It was found that Li[BOB]·nH2O salts were not readily suitable for the synthesis of high-purity orthoborate-based tetraalkylphosphonium ionic liquids, as exemplified here for trihexyl(tetradecyl)phosphonium bis(oxalato)borate, [P6,6,6,14][BOB]; along with [BOB]-, a metastable transition anionic complex (TAC) of dihydroxy(oxalato)borate with oxalic acid, [B(C2O4)(OH)2·(HOOC-COOH)]-, was also formed and passed into the ionic liquid in the course of the metathesis reaction with trihexyl(tetradecyl)phosphonium chloride. On the contrary, Na[BOB] was found to be a more suitable reagent for the synthesis of this IL, because [BOB]- anions safely passed into the final IL without hydrolysis, when metathesis reactions were performed using aqueous-free media. Since ultra-pure Na[BOB] is not commercially available, in this work, a preparation protocol for ultra-pure (>99%) Na[BOB] was developed: (i) molar ratios of boric and oxalic acids were optimised to minimise boron-containing impurities, (ii) the Na[BOB] product was thoroughly purified by sequential washing of a fine powder product in hot acetonitrile and ethanol and (iii) characterised using powder X-ray diffraction and solid-state 11B MAS NMR spectroscopy. The physico-chemical properties of the prepared boron-impurity-free IL, i.e., its density, viscosity, electric conductivity, glass-transition temperature and thermal stability, were found to be significantly different from those of the previously reported [P6,6,6,14][BOB], containing ca. 45 mol% of TAC, [B(C2O4)(OH)2·(HOOC-COOH)]-. It was found that a high-purity [P6,6,6,14][BOB] prepared in this work has a considerably lower viscosity, a higher viscosity index and a wider electro-chemical window (ECW) compared to those of the sample of [P6,6,6,14][BOB] with ca. 45 mol% of TAC. Interestingly, [B(C2O4)(OH)2·(HOOC-COOH)]- in the latter sample almost completely transformed into [BOB]- anions upon heating of the IL sample at 413 K for 1 hour, as confirmed using both 11B and 13C NMR. Therefore, in this work, apart from a well-optimised synthetic protocol for boron-impurity-free [P6,6,6,14][BOB], implications of boron-containing transition anionic complexes in tetraalkylphosphonium-orthoborate ILs used in different applications were highlighted.<br />
DOI: 10.1039/d0cp05845a PMID: 33687391<br />
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[4]. ACS Omega. 2020 May 5;5(19):11151-11159. doi: 10.1021/acsomega.0c01098. eCollection 2020 May 19.<br />
Magnetic Ionic Liquids as Solvents for RNA Extraction and Preservation.<br />
Zhu C(1), Varona M(1), Anderson JL(1).<br />
Author information: (1)Department of Chemistry, Iowa State University, Ames, Iowa 50011, United States.<br />
Ribonucleic acid (RNA) is particularly sensitive to enzymatic degradation by endonucleases prior to sample analysis. In-field preservation has been a challenge for RNA sample preparation. Very recently, hydrophobic magnetic ionic liquids (MIL) have shown significant promise in the area of RNA extraction. In this study, MILs were synthesized and employed as solvents for the extraction and preservation of RNA in aqueous solution. RNA samples obtained from yeast cells were extracted and preserved by the trihexyl(tetradecyl) phosphonium tris(hexafluoroacetylaceto)cobaltate(II) ([P66614 +][Co(hfacac)3 -]) and trihexyl(tetradecyl) phosphonium tris(phenyltrifluoroacetylaceto)cobaltate(II) ([P66614 +][Co(Phtfacac)3 -]) MIL with a dispersion of the supporting media, polypropylene glycol, at room temperature for up to a 7 and 15 day period, respectively. High-quality RNA treated with ribonuclease A (RNase A) was recovered from the tetra(1-octylimidazole)cobaltate(II) di(l-glutamate) ([Co(OIM)4 2+][Glu-]2) and tetra(1-octylimidazole)cobaltate(II) di(l-aspartate) ([Co(OIM)4 2+][Asp-]2) MILs after a 24 h period at room temperature. Quantitative reverse transcription polymerase chain reaction (qRT-PCR) and agarose gel electrophoresis were used to determine the effect of RNA preservation. Furthermore, the preservation mechanism was investigated by exploring the partitioning of RNase A into the MIL using high-performance liquid chromatography.<br />
DOI: 10.1021/acsomega.0c01098 PMCID: PMC7241037 PMID: 32455238<br />
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[5]. Anal Bioanal Chem. 2021 Jan;413(1):205-214. doi: 10.1007/s00216-020-02992-z. Epub 2020 Oct 23.<br />
A gadolinium-based magnetic ionic liquid for dispersive liquid-liquid microextraction.<br />
Abdelaziz MA(1)(2), Mansour FR(3)(4), Danielson ND(5).<br />
Author information: (1)Department of Chemistry and Biochemistry, Miami University, 651 E. High Street, Oxford, OH, 45056, USA. (2)Department of Pharmaceutical Analytical Chemistry, Faculty of Pharmacy, Kafrelsheikh University, Kafrelsheikh, 33511, Egypt. (3)Department of Pharmaceutical Analytical Chemistry, Faculty of Pharmacy, Tanta University, Tanta, 31111, Egypt. (4)Pharmaceutical Services Center, Faculty of Pharmacy, Tanta University, Tanta, 31111, Egypt. (5)Department of Chemistry and Biochemistry, Miami University, 651 E. High Street, Oxford, OH, 45056, USA. [email protected].<br />
A hydrophobic gadolinium-based magnetic ionic liquid (MIL) was investigated for the first time as an extraction solvent in dispersive liquid-liquid microextraction (DLLME). The tested MIL was composed of trihexyl(tetradecyl)phosphonium cations and paramagnetic gadolinium chloride anions. The prepared MIL showed low water miscibility, reasonable viscosity, markedly high magnetic susceptibility, adequate chemical stability, low UV background, and compatibility with reversed-phase HPLC solvents. These features resulted in a more efficient extraction than the corresponding iron or manganese analogues. Accordingly, the overall method sensitivity and reproducibility were improved, and the analysis time was reduced. The applicability of the proposed MIL was examined through the microextraction of four sartan antihypertensive drugs from aqueous samples followed by reversed-phase HPLC with UV detection at 240 nm. The DLLME procedures were optimized for disperser solvent type, MIL mass, disperser solvent volume, as well as acid, base, and salt addition. The limits of quantitation (LOQs) obtained with the analysis of 1.2-mL samples after DLLME and HPLC were 80, 30, 40, and 160 ng/mL for azilsartan medoxomil, irbesartan, telmisartan, and valsartan, respectively. Correlation coefficients were greater than 0.9988 and RSD values were in the range of 2.48-4.07%. Under the optimized microextraction conditions and using a 5-mL sample volume, enrichment factors were raised from about 40 for all sartans using a 1.2-mL sample to 175, 176, 169, and 103 for azilsartan medoxomil, irbesartan, valsartan, and telmisartan, respectively. The relative extraction recoveries for the studied sartans in river water varied from 82.5 to 101.48% at a spiked concentration of 0.5 μg/mL for telmisartan and irbesartan and 1 μg/mL for azilsartan medoxomil and valsartan. Graphical abstract.<br />
DOI: 10.1007/s00216-020-02992-z PMCID: PMC7581952 PMID: 33095289
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