Separation Of Aqueous Phase Research Articles

Energy recoveries and heavy metal migration behaviors of different oily sludges treated by pyrolysis versus solvent extraction

The pyrolysis and trace element mitigation characteristics are investigated by contrast to solvent extraction for four oily sludges, including storage tank bottom sediment (OS-1), scum from a wastewater separator (OS-2), white-clay-adsorbed waste oil (OS-3), and settlings from wastewater treatment (OS-4). Slow pyrolysis at 700 °C generated a single oil phase for OS-1 and separate oil and aqueous phases for OS-2, OS-3 and OS-4. Up to 73.0–88.3 % of the total energy were recovered from OS-1, OS-2 and OS-3 in the oil phase with 19.9–77.1 % oil yield; however, the oil phase from OS-4 accounted for only 13.3 % of the total energy, while the aqueous product accounted for 68.0 % of the total energy. Quantification of 16 trace elements revealed that OS-2 and OS-4 had much higher contents of Cu/Zn/As/Se/Cd/Pb and Ni/Cu/Zn/Se/Cd contents than the average crustal abundances, respectively. Correlations between evaporation and extraction rates indicated that the mitigation behaviors of trace elements were related to their occurrence modes in different oily sludges. Except for Cd, As and Se, all other trace elements were enriched in the pyrolysis residues of the oily sludges. Ni in the pyrolysis residue of OS-4 posed a moderate potential ecological risk.

Preparation of light weight paraffin microspheres based on CO2/N2 switchable emulsion for enhancing plugging performance of drilling fluid

Owing to the synthesis complexity and environmental hazards for the preparation of paraffin sealants by conventional methods, an alternative strategy for paraffin microspheres preparation was still required. Herein, a simplified and economic method based on CO2/N2 switchable paraffin emulsion that was stabilized by surfactant tween-80/span-80 system, was proposed for paraffin microspheres preparation. Paraffin microspheres were obtained upon CO2-induced stability changes of emulsion. The prepared paraffin microsphere has a small mean diameter of 8814.5 nm which meets the demand for the particle size of practical production. With the paraffin microsphere dosage of 0.5%, the mud cake permeability decreased to 50.4%, which indicates the good plugging performance of microspheres. When repeatedly preparing the separated aqueous phase and the recovered emulsion containing dissolved emulsion, it was found that the mean diameter of paraffin microspheres changed slight, which indicates the recyclability of switchable solvent. Paraffin microspheres, as plugging additive, pose remarkable effects on other properties of drilling fluid. It was found that the density decreased from 1.05 g/cm3 to 0.89 g/cm3, AV from 4.0 to 10.50, PV from 1.0 to 7.50, YP from 1.0 to 3.0, and FLAPI decrease continually with the paraffin microspheres dosage increases to 2.5%. The recovery rate of shale is above 80% with the introduction of paraffin microspheres, which indicates that paraffin microspheres emulsion has good compatibility with drilling fluid matrix in a certain range. Herein, a paraffin microspheres preparation method based on CO2/N2 switchable emulsion is also proposed which has wide application in the preparation of paraffin microspheres.

The Math Correlation of Material Chemistry and Physical Factors on Phase Inversion in the Separation of Aqueous and Organic Phases in an Agitated Vessel

The Math Correlation of Material Chemistry and Physical Factors on Phase Inversion in the Separation of Aqueous and Organic Phases in an Agitated Vessel

Bioinspired Processing of Keratin into Upcycled Fibers through pH-Induced Coacervation.

Keratin is an important byproduct of the animal industry, but almost all of it ends up in landfills due to a lack of efficient recycling methods. To make better use of keratin-based natural resources, the current extraction and processing strategies need to be improved or replaced by more sustainable and cost-effective processes. Here, we developed a simple and environmentally benign method to process extracted keratin, using HCl to induce the formation of a coacervate, a separate aqueous phase with a very high protein concentration. Remarkably, this pH-induced coacervation did not result in the denaturation of keratin, and we could even observe an increase in the amount of ordered secondary structures. The low-pH coacervates could be extruded and wet-spun into high-performance keratin fibers, without requiring heating or any organic solvents. The secondary structure of keratin was largely conserved in these regenerated fibers, which exhibited excellent mechanical performance. The process developed in this study represents a simple and environmentally friendly strategy to upcycle waste keratin into high-performance materials.

Experimental based CO2 transport specification ensuring material integrity

Material choice has a large impact on the total cost of the CO2 transport system for carbon capture and storage (CCS). Cost-considerations make carbon steel the preferred candidate for long pipelines. As carbon steel will corrode if aqueous phases are present, it is important to control the CO2 composition and operate the system such that formation of water containing phases is avoided.There are many suggested specifications and recommendations for the type and concentration of impurities to be allowed in the CO2 stream. The impurity limits were often set from a health, safety, and environmental point of view and are due to lack of knowledge not so much based on material integrity issues. This gap of knowledge makes it difficult to define a specification that will ensure safe operation and long-term integrity.The present paper summarises the results of a large research project that systematically tested CO2 with various combinations and concentrations of potentially reactive impurities (H2O, NO2, SO2, H2S, O2). It was clearly shown that many impurity combinations were basically inert, while other resulted in chemical reactions and some combinations even resulted in the formation of a separate aqueous phase that contained high concentrations of sulfuric and nitric acid as well as elemental sulphur. This aqueous phase was corrosive to carbon steel. Corrosion was also observed in certain situations even when a separate aqueous phase was not observed visually.It is important to avoid precipitation of solid products since it may cause problems at the injection point and in the reservoir. The present work demonstrated that the types and combination of impurities that are present are important for the maximum impurity concentration that can be allowed before chemical reactions and corrosion occur. For the investigated conditions, 100 bar and 25 °C, the concentration limit for each impurity should be below 20 ppmv if NO2, SO2, H2S, O2 are present together. The limits may be different at other temperatures and pressures.

Droplet-assisted electrospray phase separation using an integrated silicon microfluidic platform.

We report a silicon microfluidic platform that enables monolithic integration of transparent micron-scale microfluidic channels, an on-chip segmentation of analyte flows into picoliter-volume droplets, and a nano-electrospray ionization emitter that enables spatial and temporal separation of oil and aqueous phases during electro-spray for subsequent mass spectrometry analysis.

Ternary liquid-liquid equilibrium for eugenol + tert-butanol + water and eugenol + 1-octanol + water systems at 303.15 K and atmospheric pressure

The objective of this work was to determine ternary liquid-liquid equilibrium for eugenol + tert-butanol + water and eugenol + 1-octanol + water systems at 303.15K and atmospheric pressure. The experimental apparatus was 25 mL equilibrium cell equipped jacketed water connected to water bath to maintain equilibrium temperature at constant value. The procedure of this experiment was conducted by inserting mixture of eugenol + tert-butanol + water and eugenol + 1-octanol + water systems at certain composition into equilibrium cell. The solution was stirred for 4 hours and then was allowed for 20 hours in order to separate aqueous and organic phases completely. The equilibrium compositions of each phase were analysed using gas chromatography. The experimental data obtained in this work were correlated with NRTL and UNIQUAC models giving root standard mean deviation of 1.1% and 1.5%, respectively for eugenol + tert-butanol + water system and that of 2.8 % and 3.1%, respectively for eugenol + 1-octanol + water system. 1-octanol which has better capability than tert-butanol as a solvent for eugenol.

In-line characterisation of continuous phase conductivity in slurry flows using artificial intelligence tomography

Electrical Impedance Tomography (EIT) can be applied to monitor a variety of mineral and chemical processes including: velocity measurements in drilling cuttings and hydrocyclone operations. Hydraulic conveying systems rely upon the knowledge of slurry density to ensure efficient transportation of the solids. Typically, density measurements exploit the attenuation of gamma ray photons which poses complex safety, operational and regulatory concerns with Electrical Impedance Tomography affording a non-nuclear alternative to traditional approaches. To optimise the accuracy of this non-nuclear density measurement, the electrical conductivity of the aqueous phase in a multi-component slurry, is required. Whilst conductivity probes are sufficiently accurate, there are often drawbacks and limitations due to installation restrictions, as it is difficult to separate aqueous and solid phases in real-time. Electrical Impedance Fingerprinting (EIF), is a novel measurement technique which characterises formulation properties, in-situ, based upon electrical impedance sensing and artificial intelligence algorithms. This paper outlines the development of EIF and its application to monitor aqueous phase conductivity in multi-component slurries, containing sands and clays. EIF accurately predicts this conductivity with high accuracy and a root-mean squared error of 0.055 mS cm−1. This development ensures accurate non-nuclear density measurements (<5%) are obtained across an extended aqueous electrical conductivity range of 1.5–70 mS cm−1. This encompasses the majority of target hydraulic conveying systems in mining operations. EIF also enhances the functionality of ‘traditional’ electrical tomography as not only are mineral processes able to be visualised, but the process materials are simultaneously characterised, to improve process understanding, optimisation and control.

Gas–particle partitioning of polyol tracers at a suburban site in Nanjing, east China: increased partitioning to the particle phase

Abstract. Gas–particle partitioning of water-soluble organic compounds plays a significant role in influencing the formation, transport, and lifetime of organic aerosols in the atmosphere, but is poorly characterized. In this work, gas- and particle-phase concentrations of isoprene oxidation products (C5-alkene triols and 2-methylterols), levoglucosan, and sugar polyols were measured simultaneously at a suburban site of the western Yangtze River Delta in east China. All target polyols were primarily distributed into the particle phase (85.9 %–99.8 %). Given the uncertainties in measurements and vapor pressure predictions, a dependence of particle-phase fractions on vapor pressures cannot be determined. To explore the impact of aerosol liquid water on gas–particle partitioning of polyol tracers, three partitioning schemes (Cases 1–3) were proposed based on equilibriums of gas vs. organic and aqueous phases in aerosols. If particulate organic matter (OM) is presumed as the only absorbing phase (Case 1), the measurement-based absorptive partitioning coefficients (Kp,OMm) of isoprene oxidation products and levoglucosan were more than 10 times greater than predicted values (Kp,OMt). The agreement between Kp,OMm and Kp,OMt was substantially improved when solubility in a separate aqueous phase was included, whenever water-soluble and water-insoluble OM partitioned into separate (Case 2) or single (Case 3) liquid phases, suggesting that the partitioning of polyol tracers into the aqueous phase in aerosols should not be ignored. The measurement-based effective Henry's law coefficients (KH,em) of polyol tracers were orders of magnitude higher than their predicted values in pure water (KH,wt). Due to the moderate correlations between log⁡(KH,em/KH,wt) and molality of sulfate ions, the gap between KH,em and KH,wt of polyol tracers could not be fully parameterized by the equation defining “salting-in” effects and might be ascribed to mechanisms of reactive uptake, aqueous phase reaction, “like-dissolves-like” principle, etc. These study results also partly reveal the discrepancy between observation and modeling of organic aerosols.

Experimental based CO2 transport specification ensuring material integrity

Material choice has a large impact on the total cost of the transport system for carbon capture and storage (CCS). Cost-considerations make carbon steel the preferred candidate for the pipelines. As carbon steel will corrode if aqueous phases are present, it is important to control the CO2 composition and operate the system such that formation of water containing phases is avoided. There are many suggested specifications and recommendations for the type and concentration of impurities to be allowed in the CO2 stream. These impurity limits are often set from a health, safety, and environmental point of view and due to lack of knowledge are not so much based on material integrity issues. This gap of knowledge makes it difficult to make a specification that will ensure safe operation and long-term integrity. The present paper summarises the results of a large research project that systematically tested CO2 with various combinations and concentrations of potentially reactive impurities (H2O, NO2, SO2, H2S, O2). It was clearly shown that many impurity combinations were basically inert, while other resulted in chemical reactions and some combinations even resulted in formation of a separate aqueous phase that contained high concentrations of sulfuric and nitric acid as well as elemental sulphur. This aqueous phase was corrosive to carbon steel. Corrosion was also observed in certain situations even if a separate aqueous phase was not observed visually. It is important to avoid precipitation of solid products since it may cause problems at the injection point and in the reservoir. The present work demonstrated that the types and combination of impurities that are present is important for the maximum impurity concentration that can be allowed to prevent chemical reactions and corrosion from occurring. The concentration limit for each impurity should be below 20 ppmv if NO2, SO2, H2S, O2 are present together.

Hydrophilic role of deep eutectic solvents for clean synthesis of biphenyls over a magnetically separable Pd-catalyzed Suzuki-Miyaura coupling reaction

The development of an efficient and sustainable catalytic system for the preparation of biphenyls through the Suzuki-Miyaura coupling reaction is still a great challenge to green chemistry. Encouraging the prevailing challenge, in the present work, a heterogeneous Pd catalyst was synthesized through a green method and used for the production of biphenyls in deep eutectic solvents (DESs) as green reaction media. In order to prepare the catalyst, magnetite-graphene oxide nanocomposite was modified with cellulose via the click reaction and applied as support for Pd nanoparticles. Cellulose acted as both reducing and stabilizing agent for Pd nanoparticles and eliminated the requirement of a reducing agent. The prepared catalyst was characterized by different methods such as FT-IR, EDX, EDX-mapping, XPS, SEM, TEM, XRD, VSM, and ICP-OES analyses. Catalytic properties of the obtained catalyst was explored in the coupling reaction of aryl halides with aryl boronic acids in different hydrophilic and hydrophobic DESs. The presence of cellulose with hydrophilic character on the structure of catalyst offered well dispersion of the catalyst in hydrophilic DESs, which led to enhancement of its catalytic activity. Among various hydrophilic DESs, the DES composed of dimethylammonium chloride and glycerol was verified as the most effective solvent for the preparation of biphenyls. The catalyst was compatible with a variety of substrates, with which all the Suzuki coupling products were achieved in high to excellent yields. Thanks to the low solubility of catalyst and DES in organic solvents, the separated aqueous phase containing both of the catalyst and DES could be readily recovered by evaporating water and reused up to five successive runs with a stable activity. This simple and new separation strategy provided a clean and highly efficient synthetic methodology for the synthesis of various biphenyls. Moreover, hot filtration test efficiently confirmed that the catalyst is heterogeneous and completely stable under reaction conditions.

Development and Validation of a Method for Quantification of 28 Psychotropic Drugs in Postmortem Blood Samples by Modified Micro-QuEChERS and LC–MS-MS

The development of new sample preparation alternatives in analytical toxicology leading to quick, effective, automated and environmentally friendly procedures is growing in importance. One of these alternatives is the QuEChERS, originally developed for the analysis of pesticide residues, producing cleaner extracts than liquid-liquid extraction, and easier separation of aqueous and organic phases. However, there are few published studies on the miniaturization of this technique for forensic toxicology, especially in postmortem analysis. We developed and validated a modified micro-QuEChERS and LC-MS-MS assay to quantify 16 antidepressants, 7 antipsychotics and 3 metabolites and semi-quantify norfluoxetine and norsertraline in postmortem blood. The calibration curve was linear from 1 to 500 ng/mL, achieved an r > 0.99, with all standards quantifying within ±15% of target except ±20% at the limit of quantification of 1 ng/mL for 26 substances. The F test was applied to evaluate if the variance between replicates remained constant for all calibrators. Six weighting factors were analyzed (1/x, 1/x2, 1/x0,5, 1/y, 1/y2 and 1/y0,5), with the weighting factor with the lowest sum of residual regression errors (1/x2) selected. No endogenous or exogenous interferences were observed. Method imprecision and bias were <19.0% and 19.7%, respectively. Advantages of this method include a low sample volume of 100 µL, simple but effective sample preparation and a rapid 8.5-min run time. The validated analytical method was successfully applied to the analysis of 100 authentic postmortem samples.

Pd supported on clicked cellulose-modified magnetite-graphene oxide nanocomposite for C-C coupling reactions in deep eutectic solvent

Cellulose-modified magnetite-graphene oxide nanocomposite was prepared via click reaction and utilized for immobilization of palladium (Pd) nanoparticles without using additional reducing agent. The abundant OH groups of cellulose provided the uniform dispersion and high stability of Pd nanoparticles, while magnetite-graphene oxide as a supporting material offered high specific surface area and easy magnetic separation. The as-prepared nanocomposite served as a heterogeneous catalyst for the Heck and Sonogashira coupling reactions in various hydrophilic and hydrophobic deep eutectic solvents (DESs) as sustainable and environmentally benign reaction media. Among the fifteen DESs evaluated for coupling reactions, the hydrophilic DES composed of dimethyl ammonium chloride and glycerol exhibited the best results. Due to the low miscibility of catalyst and DES in organic solvents, the separated aqueous phase containing both of the catalyst and DES can be readily recovered by evaporating water and retrieved eight times with negligible loss of catalytic performance.

THE DEVELOPMENT OF THE METHOD FOR TYLOSIN RESIDUES DETERMINATION IN EGG SAMPLES USING THE METHOD OF ENZYME-LINKED IMMUNOSORBENT ASSAY

The article presents the results of development and validation of the method of eggs sample preparation for the determination of tylosin residues by enzyme-linked immunosorbent assay using the kits manufactured by Europroxima (Netherlands). Tylosin is a natural antibiotic, highly effective against gram-positive and selectively active against gram-negative organisms. It is a product of microbiological synthesis of Streptomyces fradiae. Irresponsible use of antibiotics and the non-compliance with the withdrawal period for animals after their use have escalated the problems associated with the presence of antibiotic residues in food. Biologically reasonable maximum permissible levels (MRLs) of residual antimicrobials in animal products, officially approved in all countries by the Commission of the Codex Alimentarius, in the European Union by EU Regulation № 37/2010, and in Ukraine by the Order of the Ministry of Health of Ukraine products.&#x0D; In order to ensure the compliance with the above standards, it is necessary to have sensitive and specific analytical methods that can rapidly and effectively control the presence of residues at the established levels for routine control of antibiotics in eggs by veterinary and manufacturing laboratories.&#x0D; The influence of different extraction conditions on the percentage of extraction of the target analyte from the homogenized eggs sample fortified with the standard solution was investigated: pH changes of different buffer solutions, different degrees of sample concentration, the influence of separate reagents for the better separation of aqueous and organic phases. The results of the quantitative analysis of tylosin content in the model samples, determined by the developed screening method, were confirmed by liquid chromatography with mass spectrometric detection. Optimal conditions for extraction of the target analyte from egg were provided by the sample preparation method using the extraction with 0.5 M potassium phosphate buffer with pH 8.0, followed by the analyte transfer into the organic phase, the concentration of the analyte by evaporation of an organic extract aliquot and the reconstitution of the dried residue in the buffer solution, degreasing with hexane. It was found that for the better phase separation in "buffer – ethyl acetate" system the procedure of extraction and phase separation is best carried out at room temperature. The research results are presented in tables and chromatograms.&#x0D; The proposed screening method was validated, the necessary statistical analysis of the obtained results was performed, and as a result, the limit value or “technical threshold” and the cut-off factor were calculated, and their graphical representation was presented.&#x0D; The main advantages of the developed method are the rapidity, the simplicity of performance and the sensitivity to the target analyte at the level of 2 μg/kg, which is confirmed statistically by the results of validation tests. The technique is offered to the manufacturer to expand the scope of the kits usage.

A SALTING-OUT ASSISTED LIQUID-LIQUID EXTRACTION FOR THE DETERMINATION OF TEBUCONAZOLE, CARBOFURAN AND IMIDACLOPRID IN WHITE AND ROSÉ WINES

Food safety is a constant and necessary concern due to the worldwide increase of the food demand. The monitoring of quality parameters demands the development of accurate, easy and fast procedures. The aim of this work was to develop a cheap, miniaturized and trustworthy salting-out assisted liquid-liquid extraction (SALLE) procedure for the determination of pesticides in wines. Sample and acetonitrile were mixed and the addition of NaCl and CH3COONa were used for separation of aqueous and organic phases. After centrifugation, the organic phase was directly injected into a liquid chromatograph. The developed SALLE procedure consumed at least 25-fold less reagent compared to conventional QuEChERS procedure. Additionally, the d-SPE step of the QuEChERS method was suppressed, without efficiency losses. The developed procedure was compared to the conventional methodology and no significant difference was observed. It was successfully applied to the determination of three pesticides in wines by liquid chromatography. Low consumption of sample and solvent, low residues generation, simple instrumentation are notable advantages. The suppression of the d-SPE step simplified the process and the risk of analyte losses.

Effect of Different Types of Wave Exposure on Demulsification of Stable Gel-Containing Water-in-Oil Emulsions

An original method for wave-exposed sample preparation of commercial stable gel-containing water-in-oil emulsions is developed to separate aqueous and oil phases that are present in the composition for their subsequent analysis. Real samples of commercial stable water-in-oil emulsions differing in composition (different contents of water, gel, iron sulfide, and mechanical impurities) are studied. The effect of the intensity and duration of exposure to waves of different nature on the completeness of phase separation in real samples of commercial emulsions of different composition are studied. The possibility in principal to separate oil and aqueous phases from the composition of stable water-in-oil emulsions stabilized by gel-like associates under exposure to waves (permanent magnetic field, electromagnetic field, and ultrasonic vibrations) is shown. When a water-in-oil emulsion is exposed to a permanent magnetic field with a induction in the range of 0.1–0.57 T for 1–3 min, the degree of isolation of water from the emulsion samples under study varies in the range from 48 to 71%, depending on the composition of the emulsion under study. Similar results are obtained under direct current and alternating current electromagnetic fields with a magnetic induction of 0.1–1.0 T. For complete separation of aqueous and oil phases from gel-containing water-in-oil emulsions, we propose to use ultrasonic treatment combined with the addition of a suspension of aluminum oxide nanopowder in acetonitrile. In this case, the complete destruction of the gel and 100% separation of the aqueous and oil phases are observed.

Effect of crystallization of oil phase on the destabilization of O/W emulsions containing vegetable oils with low melting points

Mayonnaise is a preferred dressing that is routinely used in many regions. Distribution of products containing frozen mayonnaise is highly desirable due to the development of cold chain and changing lifestyle. However, freezing and thawing of mayonnaise result into separate oil and aqueous phases. A detailed mechanism of this phenomenon is still unknown. In this study, the destabilization of frozen emulsions, using rapeseed, safflower, olive, rice bran, and soybean oils as the oil phase was examined, in which these oil phases crystallize at lower temperature than the aqueous one. The vegetable oils exhibit different crystallization behavior. Irrespective of the type of vegetable oil, it was found that smaller the difference between the storage temperature and the melting point of the oil, which was estimated from the fatty acid composition, quicker was the destabilization of the emulsion prior to the growth of the oil crystal. We consider that the change in the crystallization process of the oil phase increases the energy at the oil–water interface and destabilizes the emulsion.

Microfluidic solvent extraction of calcium: Modeling and optimization of the process variables

In this study, a new systematic method was proposed for the highly efficient separation of species with very low separation factor. Here, solvent extraction and microfluidic technology were integrated for the extraction and separation of Ca2+ion. A cyclic compound (DC18C6) was used as the selective extractant. Full separation of organic and aqueous phases at the end of the microchannel was achieved by exploiting a flow regime map. N-butyl acetate was chosen as organic solvent among from other potential candidates with different characteristics. The Box-Behnken experimental design was used to provide data for modeling, while the variables of the model were DC18C6 concentration, flow rate and pH of the aqueous phase. The results showed that Ca2+ extraction efficiency was 62.28% under the optimum conditions: DC18C6 concentration was 0.014 M, the aqueous phaseflow rate was 20 µl/min and pH of the aqueous phase was 5.1. Multi-stage microfluidic solvent extraction in series was performed and the possibility of numbering-up with maintaining full phase separation was demonstrated. The overall volumetric mass transfer coefficients were determined quantitatively in a single microchannel, and their values were in the ranges of 0.19–0.41 s−1, which are two orders of magnitude higher than those of conventional liquid-liquid contactors.

Coacervation of Lipid Bilayer in Natural Cell Membranes for Extraction, Fractionation, and Enrichment of Proteins in Proteomics Studies.

This is the first report where hexafluoroisopropanol (HFIP) was used to induce the coacervation of lipid components in natural cell membranes that would concomitantly result in solubilization, extraction, and enrichment of hydrophobic proteins (e.g., integral membrane proteins, IMP) into the coacervate phase, and extraction of hydrophilic proteins in a separate aqueous phase. The incorporation of this innovative approach in the proteomics workflow would allow the fractionation of proteins in separate aqueous and coacervate phases and would also eliminate the need for using surfactants. Subsequently, proteins can be identified by the bottom-up proteomics approach where samples were digested in solution after phase separation. Yeast cell wall proteins, anchored membrane proteins, and proteins related to some regulatory activities were mostly found in the aqueous-rich phase. On the other hand, most integral membrane proteins, proteins involved in metabolic processes, and proteins responsible for ions or drug binding were identified in the coacervate phase. The detergent-free, facile, and rapid process of natural lipid coacervation increased the number of identified proteins by 8% (vs no-phase separation experiment). The identification of all IMPs and organelle IMPs was improved by 13% and 29%, respectively. In addition, 25% more low-abundance proteins (less than 20 ppm) were identified.

Investigation of possible aqueous phase formation during vaporization of sevoflurane.

Background and Aims:Ultane® (sevoflurane; AbbVie Inc., North Chicago, IL, USA) has a dissolved water content of approximately 0.035% weight/weight (w/w). A previous report described formation of an aqueous layer in 4 of 13 sevoflurane vaporizers used in operating rooms. We investigated the conditions under which an aqueous layer could develop during vaporization of sevoflurane–water mixtures.Material and Methods:A temperature-controlled glass reactor was used to simulate a vaporizer. In four experiments, the vaporization of different sevoflurane–water mixtures was monitored over approximately 3–4 days. Samples were removed at regular intervals for analysis of water content. For confirmation, one experiment was replicated in a Tec 7 vaporizer.Results:Saturation of sevoflurane with water occurred at 0.11%–0.13% w/w at an ambient temperature; at greater water concentrations a separate aqueous phase was initially present. The sevoflurane–water azeotrope contained approximately 1.2% w/w water at 25°C. When the initial water content was <1.2% w/w (0.11%–1.03% w/w), vaporization resulted in a single phase of drier sevoflurane (final water concentration 0.02%–0.08% w/w). When the starting water concentration exceeded the azeotropic concentration (5.0% w/w), vaporization increased the water content, reaching 13% w/w at 71 h. Results under the low initial water condition were similar in the Tec 7 vaporizer.Conclusions:An increase in water concentration following vaporization of sevoflurane can only occur when the starting water content is higher than the azeotropic concentration and therefore cannot originate from the dissolved water present in the marketed product because the water concentration in Ultane® is 34 times lower than the azeotropic concentration.