Morpholinium-based ionic liquids show antimicrobial activity against clinical isolates of Pseudomonas aeruginosa.

Pseudomonas aeruginosa is a multi-drug resistant (MDR) pathogen. It is classified by WHO as one of the most life-threatening pathogens causing nosocomial infections. Some of its clinical isolates and their subpopulations show high persistence to many antibiotics that are recommended by the European Committee on Antimicrobial Susceptibility Testing (EUCAST). Thus, there is a need for non-traditional classes of antibiotics to fight the increasing threat of MDR P. aeruginosa. Ionic liquids (IL) are one such promising class of novel antibiotics. We selected four strains of P. aeruginosa and studied the growth inhibition and other effects of 12 different ILs. We used the well-characterized P. aeruginosa PAO1 (ATCC 15692) as model strain and compared it to three other isolates from chronic lung infection (LES B58), skin burn infection (UCBPP-PA14) and keratitis infection (39016), respectively. The ILs consisted of either 4,4-didecylmorpholinium [Dec2Mor]+ or 4-decyl-4-ethylmorpholinium [DecEtMor]+ cations combined with different anions. We found that the ILs with 4,4-didecylmorpholinium [Dec2Mor]+ cations most effectively inhibited bacterial growth as well as reduced strain fitness and virulence factor production. Our results indicate that these ILs could be used to treat P. aeruginosa infections.

Determination of sulfonylureas in cereal samples with electrophoretic method using ionic liquid with dispersed carbon nanotubes as electrophoretic buffer.

A capillary electrophoresis method to determine four sulfonylureas in grain samples was developed using 10mM of 1-butyl-3-methyl imidazolium tetrafluoroborate (bminBF4) as electrophoretic buffer solution. 2mgL(-1) of Surfactant Coated-Single Wall-Carbon Nanotubes (SC-SWCNTs) was added to the buffer solution to improve the resolution. In this way, the separation of nicosulfuron, ethoxysulfuron, sulfometuron methyl and chlorsulfuron was carried out in 16min without using organic solvents. A clean up-preconcentration procedure was done prior to inject the sample into the CE instrument, in order to achieve the established maximum residue limits (MRLs). So, the detection limits (LODs) for each analytes were between 16.8 and 26.6µgkg(-1). The relative standard deviations (RSDs) were in the range 1.9-6.7%. A recovery study using the so-called matrix matched calibration demonstrates that no matrix interferences were found throughout the determination. The recovery percentages were ranged between 80% and 113%.

Separation of ionic liquid [Mmim][DMP] and glucose from enzymatic hydrolysis mixture of cellulose using alumina column chromatography.

Pretreatment of cellulose with ionic liquids (ILs) can improve the efficiency of the hydrolysis by increasing the surface area of the substrates accessible to solvents and cellulases. However, the IL methods are facing challenges to separate the hydrolyzed sugar products as well as the renewable ILs from the complex hydrolysis mixtures. In this study, an alumina column chromatography (ACC) method was developed for the separation of hydrophilic IL N-methyl-N-methylimidazolium dimethyl phosphate ([Mmim][DMP]) and glucose, which was the main ingredient of the monosaccharide hydrolyzate. The processing parameters involved in ACC separation were investigated in detail. Our results showed that the recovery yields of [Mmim][DMP] and glucose can reach up to 93.38% and 90.14%, respectively, under the optimized parameters: the sampling ratio of 1:20 between the applied sample volume and the bed volume of the column; a gradient elution using methanol (100%, 150 ml) and then water (170 ml) as eluents with 1 ml/min flow rate. The recovered [Mmim][DMP] showed qualified property and was effective in a new hydrolysis reaction. In addition, scale-up ACC separations were successfully done with satisfied separation performance. The results indicated that the ACC is one of the available methods for the separation of ILs and monosaccharides from the hydrolysis mixtures.

On the dielectric conductivity of molecular ionic liquids.

The contribution of the conductivity to the spectrum of the generalized dielectric constant or susceptibility of molecular ionic liquids is analyzed, both in theoretical terms and computationally by means of molecular dynamics simulation of the concrete system 1-ethyl-3-methyl-imidazolium dicyanoamide at 300 K. As a central quantity the simulated current autocorrelation function is modeled by a carefully designed fit function. This not only gives a satisfactory numerical representation but yields the correct conductivity upon integration. In addition the fit function can be Fourier-Laplace transformed analytically. Both, the real and imaginary parts of the transform show expected behavior, in particular, the right limits for zero frequency. This altogether demonstrates that the components of the fit function are of physical relevance.