Name: chemical analysis of water-accommodated fractions of crude oil spills using tims-ft-icr ms
Uploaded: 2017-03-03T14:00:00
Description: Watch this Scientific Journal Video about Chemical Analysis of Water-accommodated Fractions of Crude Oil Spills Using TIMS-FT-ICR MS at JoVE.com

This work was supported by the National Institute of Health (Grant No. R00GM106414 to FFL). We would like to acknowledge the Advanced Mass Spectrometry Facility of Florida International University for their support.

1. Preparation of the Low-energy Water-accommodated Fractions (LEWAF)
<ol>
	<li>Clean 2-L aspirator bottles by rinsing the bottles with methylene chloride in order to remove any potential contaminants.</li>
	<li>Fill bottles with 50&#160;mL of methylene chloride, close them, and agitate for 30 s. Drain them into the appropriate waste container. Repeat for a total of three washes.</li>
	<li>Use one aspirator bottle for the irradiation exposure and the other bottle as a control sample (perform duplicate sets of each if p...

<ol>
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G., Altin, D., Nordtug, T., Daling, P. S., Hansen, B. H. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Chemical+comparison+and+acute+toxicity+of+water+accommodated+fraction+(WAF)+of+source+and+field+collected+Macondo+oils+from+the+Deepwater+Horizon+spill.">Chemical comparison and acute toxicity of water accommodated fraction (WAF) of source and field collected Macondo oils from the Deepwater Horizon spill.</a> Mar Pollut Bull. 91 (1), 222-229 (2015).</li><li>Wang, J., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Biodegradation+of+dispersed+Macondo+crude+oil+by+indigenous+Gulf+of+Mexico+microbial+communities.">Biodegradation of dispersed Macondo crude oil by indigenous Gulf of Mexico microbial communities.</a> Science of The Total Environment. 557-558, 453-468 (2016).</li><li>McKenna, A. M., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Expansion+of+the+analytical+window+for+oil+spill+characterization+by+ultrahigh+resolution+mass+spectrometry:+beyond+gas+chromatography.">Expansion of the analytical window for oil spill characterization by ultrahigh resolution mass spectrometry: beyond gas chromatography.</a> Environ Sci Technol. 47 (13), 7530-7539 (2013).</li><li>Fernandez-Lima, F. A., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Petroleum+crude+oil+characterization+by+IMS-MS+and+FTICR+MS.">Petroleum crude oil characterization by IMS-MS and FTICR MS.</a> Anal Chem. 81 (24), 9941-9947 (2009).</li><li>Benigni, P., Marin, R., Fernandez-Lima, F. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Towards+unsupervised+polyaromatic+hydrocarbons+structural+assignment+from+SA-TIMS-FTMS+data.">Towards unsupervised polyaromatic hydrocarbons structural assignment from SA-TIMS-FTMS data.</a> Int J Ion Mobil Spectrom. 18 (3), 151-157 (2015).</li><li>Benigni, P., Thompson, C. J., Ridgeway, M. E., Park, M. A., Fernandez-Lima, F. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Targeted+high-resolution+ion+mobility+separation+coupled+to+ultrahigh-resolution+mass+spectrometry+of+endocrine+disruptors+in+complex+mixtures.">Targeted high-resolution ion mobility separation coupled to ultrahigh-resolution mass spectrometry of endocrine disruptors in complex mixtures.</a> Anal Chem. 87 (8), 4321-4325 (2015).</li><li>Benigni, P., Fernandez-Lima, F. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Oversampling+Selective+Accumulation+Trapped+Ion+Mobility+Spectrometry+coupled+to+FT-ICR+MS:+Fundamentals+and+Applications.">Oversampling Selective Accumulation Trapped Ion Mobility Spectrometry coupled to FT-ICR MS: Fundamentals and Applications.</a> Analytical Chemistry. , (2016).</li><li>Castellanos, A., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Fast+Screening+of+Polycyclic+Aromatic+Hydrocarbons+using+Trapped+Ion+Mobility+Spectrometry+Mass+Spectrometry.">Fast Screening of Polycyclic Aromatic Hydrocarbons using Trapped Ion Mobility Spectrometry Mass Spectrometry.</a> Anal Methods. 6 (23), 9328-9332 (2014).</li><li>Benigni, P., DeBord, J. D., Thompson, C. J., Gardinali, P., Fernandez-Lima, F. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Increasing+Polyaromatic+Hydrocarbon+(PAH)+Molecular+Coverage+during+Fossil+Oil+Analysis+by+Combining+Gas+Chromatography+and+Atmospheric-Pressure+Laser+Ionization+Fourier+Transform+Ion+Cyclotron+Resonance+Mass+Spectrometry+(FT-ICR+MS).">Increasing Polyaromatic Hydrocarbon (PAH) Molecular Coverage during Fossil Oil Analysis by Combining Gas Chromatography and Atmospheric-Pressure Laser Ionization Fourier Transform Ion Cyclotron Resonance Mass Spectrometry (FT-ICR MS).</a> Energy &amp; Fuels. 30 (1), 196-203 (2016).</li><li>Qi, Y., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Absorption-Mode+Fourier+Transform+Mass+Spectrometry:+the+Effects+of+Apodization+and+Phasing+on+Modified+Protein+Spectra.">Absorption-Mode Fourier Transform Mass Spectrometry: the Effects of Apodization and Phasing on Modified Protein Spectra.</a> Journal of the American Society for Mass Spectrometry. 24 (6), 828-834 (2013).</li><li>Lababidi, S., Schrader, W. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Online+normal-phase+high-performance+liquid+chromatography/Fourier+transform+ion+cyclotron+resonance+mass+spectrometry:+Effects+of+different+ionization+methods+on+the+characterization+of+highly+complex+crude+oil+mixtures.">Online normal-phase high-performance liquid chromatography/Fourier transform ion cyclotron resonance mass spectrometry: Effects of different ionization methods on the characterization of highly complex crude oil mixtures.</a> Rapid Communications in Mass Spectrometry. 28 (12), 1345-1352 (2014).</li></ol>

Critical Steps within the Protocol
The chemical complexity of LEWAFs requires accurate preparation in order for the laboratory experiments to accurately reflect what occurs naturally. A valid assessment of the data hinges on three criteria: minimizing the introduction of artifacts throughout sample handling (e.g., preparation of the LEWAF, sampling, extractions, and preparation of the sample for analysis), validating the experimental protocol (i.e., using dark controls for the p...

There are numerous sources of environmental exposure to crude oil, both from natural causes and from anthropogenic exposure. Upon release to the environment, particularly in the ocean, the crude oil can undergo partitioning, with the formation of an oil slick on the surface, a loss of volatile components to the atmosphere, and sedimentation. However, low-energy mixing of the poorly soluble oil and the water does occur, and this mixture, which is not classically solubilized, forms what is referred to as the low-energy water-accommodated fraction (LEWAF). The solubilization of the oil components in the water is typically enhanced during exposure of the oil-water interface to solar radiation. This photo-solubilization of the crude oil in the ocean can undergo significant chemical changes due to this exposure to solar radiation and/or due to enzymatic degradation1,2. Understanding these chemical changes and how they occur in the presence of the bulk matrix (i.e., the crude oil) is fundamental to mitigating the effects this exposure has on the environment.
Previous studies have shown that crude oil undergoes oxygenation, particularly the polycyclic aromatic hydrocarbons (PAHs), which represent a highly toxic source of contamination that harms organisms, undergoes bio-accumulation, and is bioactive3,5,6. Understanding the products of the different oxygenation processes is challenging because they occur only in the presence of the bulk matrix. Therefore, a single, standard analysis may not be representative of the changes occurring in nature. The preparation of the LEWAF must replicate the natural processes that take place in an environmental setting. Of particular interest is the oxygenation of PAHs, which occurs due to solar radiation.
The second challenge in the study of the water-accommodated fraction is the molecular identification of the different chemical constituents in the sample. Due to the complexity of the sample, caused by its high mass and degree of oxygen, the oxygenation products are typically unsuitable for the traditional analysis carried out by gas chromatography combined with MS analysis7,8. An alternative approach is to characterize the changes in the chemical formula of the sample by utilizing ultra-high mass resolution MS techniques (e.g., FT-ICR MS). By coupling TIMS to FT-ICR MS, in addition to the isobaric separation in the MS domain, the ion mobility spectrometry (IMS) dimension provides the separation and characteristic information for the different isomers present in the sample9,10,11. Combined with an atmospheric pressure laser ionization (APLI) source, the analysis can be selective to the conjugated molecules found in the sample, allowing the changes that the PAHs undergo to be accurately characterized12,13.
In this work, we describe a protocol for the preparation of LEWAFs exposed to photo-irradiation in order to study the transformation processes of the oil components. We also illustrate the changes that occur upon photo-irradiation, as well as the procedure for sample extraction. We will also present the use of APLI with TIMS coupled with FT-ICR MS to characterize the PAHs in the LEWAF as a function of the exposure to light.

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			<td height="20" style="height:20px;width:228px;">Reagents</td>
			<td style="width:156px;"></td>
			<td style="width:156px;"></td>
			<td style="width:375px;"></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">methylene chloride</td>
			<td></td>
			<td></td>
			<td></td>
		</tr>
		<tr height="20">
			<td height="20" style="height:20px;">methanol</td>
			<td></td>
			<td></td>
			<td></td>
		</tr>
		<tr height="20">
			<td height="20" style="height:20px;">toluene</td>
			<td></td>
			<td></td>
			<td></td>
		</tr>
		<tr height="20">
			<td height="20" style="height:20px;">Na2SO4</td>
			<td></td>
			<td></td>
			<td></td>
		</tr>
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			<td height="20" style="height:20px;">Crude oil</td>
			<td></td>
			<td></td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">Instant Ocean&#174;</td>
			<td>Aquarium Systems</td>
			<td></td>
			<td>33 ppt salinity with 0.45 &#956;m pore filtration&#160;</td>
		</tr>
		<tr height="20">
			<td height="20" style="height:20px;">Name&#160;</td>
			<td>Company</td>
			<td>Catalog Number</td>
			<td>Comments</td>
		</tr>
		<tr height="20">
			<td height="20" style="height:20px;">Equipment</td>
			<td></td>
			<td></td>
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			<td height="20" style="height:20px;">Suntext XLS+</td>
			<td>Atlas Chicalo Ill, USA</td>
			<td></td>
			<td>1500 w xeon arc lamp, light intensity of 765 W/m2&#160;</td>
		</tr>
		<tr height="20">
			<td height="20" style="height:20px;">Atmospheric Pressure Laser Ionization</td>
			<td>Bruker Daltonics Inc, MA</td>
			<td></td>
			<td>Note a 266 nm laser is used</td>
		</tr>
		<tr height="20">
			<td height="20" style="height:20px;">TIMS-FT-ICR MS Instrument</td>
			<td>Bruker Daltonics Inc, MA</td>
			<td></td>
			<td>The set up we had consisted of a 7T magnet with an infinity cell</td>
		</tr>
		<tr height="20">
			<td height="20" style="height:20px;">Name&#160;</td>
			<td>Company</td>
			<td>Catalog Number</td>
			<td>Comments</td>
		</tr>
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			<td height="20" style="height:20px;">Software</td>
			<td></td>
			<td></td>
			<td></td>
		</tr>
		<tr height="20">
			<td height="20" style="height:20px;">DataAnalysis 4.2</td>
			<td>Bruker Daltonics Inc, MA</td>
			<td></td>
		</tr>
		<tr height="20">
			<td height="20" style="height:20px;">Python 2.7</td>
			<td></td>
			<td></td>
			<td>Requires Numpy, Scipy, Pandas, glob, oct2py, and os</td>
		</tr>
		<tr height="20">
			<td height="20" style="height:20px;">Octave 4.0</td>
			<td></td>
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chemical analysis of water-accommodated fractions of crude oil spills using tims-ft-icr ms

Multiple chemical processes control how crude oil is incorporated into seawater and also the chemical reactions that occur overtime. Studying this system requires the careful preparation of the sample in order to accurately replicate the natural formation of the water-accommodated fraction that occurs in nature. Low-energy water-accommodated fractions (LEWAF) are carefully prepared by mixing crude oil and water at a set ratio. Aspirator bottles are then irradiated, and at set time points, the water is sampled and extracted using standard techniques. A second challenge is the representative characterization of the sample, which must take into consideration the chemical changes that occur over time. A targeted analysis of the aromatic fraction of the LEWAF can be performed using an atmospheric-pressure laser ionization source coupled to a custom-built trapped ion mobility spectrometry&#8211;Fourier transform&#8211;ion cyclotron resonance mass spectrometer (TIMS-FT-ICR MS). The TIMS-FT-ICR MS analysis provides high-resolution ion mobility and ultrahigh-resolution MS analysis, which further allow the identification of isomeric components by their collision cross-sections (CCS) and chemical formula. Results show that as the oil-water mixture is exposed to light, there is significant photo-solubilization of the surface oil into the water. Over time, the chemical transformation of the solubilized molecules takes place, with a decrease in the number of identifications of nitrogen- and sulfur-bearing species in favor of those with a greater oxygen content than were typically observed in the base oil.

LEWAF analysis by TIMS-FT-ICR MS results in a two-dimensional spectrum based on m/z and TIMS trapping voltage. Each of the samples, taken at different time points, can therefore be characterized based on the changing chemical composition, as observed by the distribution of chemical formulas and the isomeric contribution identified by the IMS (see Figure 1). Typically, the m/z information can be utilized to assign elemental formulas to the analyzed peaks....

Watch this Scientific Journal Video about Chemical Analysis of Water-accommodated Fractions of Crude Oil Spills Using TIMS-FT-ICR MS at JoVE.com

Chemical Analysis of Water-accommodated Fractions of Crude Oil Spills Using TIMS-FT-ICR MS

The low-energy water-accommodated fraction (LEWAF) of crude oil is a challenging system to analyze, because over time, this complex mixture undergoes chemical transformations. This protocol illustrates methods for the preparation of the LEWAF sample and for performing photo-irradiation and chemical analysis by trapped ion mobility spectrometry&#8211;FT-ICR MS.

Multiple chemical processes control how crude oil is incorporated into seawater and also the chemical reactions that occur overtime. Studying this system ...

The overall goal of these experiments is to illustrate the analytical advantages of enabling emerging technologies based on TIMS-FT-ICR MS for the molecular characterization of complex mixtures, such as water-accommodated fractions for crude oils. The TIMS-FT-ICR MS coupling combines two of the most comprehensive orthogonal and alluvial techniques for the analysis of complex mixtures. TIMS-FT-ICR MS coupling permits in a single analysis the characterization of thousands of molecular components with mobility resolving powers of over 150, mass resolution of 500, 000, and sub-ppm mass accuracy.TIMS-FT-ICR MS enables the separation, identification, and quantitation at the molecular level of complex mixtures, based on differences in size, charge and mass with minimal sample appropriation. To begin the LEGAF preparation, add 50 milliliters of dicholomethane to a two liter glass aspirator bottle. Close the bottle and agitate the bottle for 30 seconds.Discard the dichloromethane wash, and repeat this process two more times. Wash one more two liter aspirator bottle in this way, then add about 1.6 liters of filtered artificial seawater with a salinity of 33 parts per thousand to each bottle. Add a stir bar, and then use a gas-tight syringe to add sufficient crude oil sample to each bottle to achieve a final concentration of one gram per liter of oil and seawater.Wrap the bottles in aluminum foil to exclude light, and stir the mixtures at approximately 100 RPM for 24 hours to finish preparing the LEWAF. It's important that care is used when first mixing the oil and water to avoid over-mixing the solution. Next, unwrap one of the LEWAF bottles in aluminum foil, leaving one as the dark control.Place the bottles in the solar irradiator with the temperature set to maintain the samples at 25 degrees Celsius. Irradiate the mixtures continuously for the desired experiment length. At set intervals during the experiment, obtain 150 milliliter fractions from each bottle by uncorking the bottle and opening the drain valve.Extract each sample aliquot using 50 milliliters of dichloromethane three times using a separatory funnel. Shake the funnel for two minutes each time, remembering to regularly vent the funnel to avoid pressure buildup. Drain the sample into a flat-bottom flask through a funnel containing sulfate and rinse the sodium sulfate with additional DCM.Concentrate the extract to 15 milliliters using a hot water bath set at 58 degrees Celsius. Transfer the concentrate into a concentration tube, rinsing the flask with DCM. Concentrate each sample to one milliliter under a gentle stream of nitrogen gas.For each concentrated sample, using a glass positive displacement micropipette, add 990 microliters of a one to one by volume mixture of methanol and toluene to a glass vial. Then mix in 10 microliters of the sample. To begin the FTR-ICR MS analysis, set the instrument to Operate mode.Draw a sample into a sample syringe. Set the infusion rate to 200 microliters per hour, the nebulizer pressure to two bar, and the vaporizer temperature to 300 degrees Celsius. Set the dry gas rate to 1.2 liters per minute and the temperature to 220 degrees Celsius.Then set the instrument to Tune mode. Based on the resulting spectrum adjust the instrument parameters and recalibrate the mass spectrometer to improve the ion transmission and detection for the desired range of mass to charge ratios. Once the instrument parameters have been optimized, exit Tune mode.Set the desired number of scans to be average per mass spectrum, and then acquire the spectrum. To begin the trapped ion mobility spectrometry analysis turn on the external breaker to the TIMS instrument to engage TIMS mode. Set the FT-ICR instrument to chromatography mode.Turn on the supplementary roughing pump and set the inlet and outlet pressures to the desired values using the TIMS control valve. Allow the pump to warm up for at least three hours, then perform a fast sweep over a wide voltage range at a low IMS and MS resolution to identify the needed voltage range for the analysis. Once the range has been identified, set the voltage per frame to 0.1 volts.Set the number of frames to cover the entirety of the DeltaV ramp and run the analysis. After performing the analyses, process the data with the appropriate software and scripts to determine the chemical composition and mobility values of identified peaks. After sunlight irradiation of an LEWAF of a crude oil sample, changes in the chemical complexity are observed as a function of exposure time.This complexity was detected and visualized in a 2D spectrum based on mass to charge ratio and ion mobility. The use of APLI resulted in greater analytical sensitivity to molecules with double bonds. Four molecular classes were identified in the sample.Distribution plots of double bond equivalents as a function of the number of carbons were used to monitor changes in the molecular composition over time. Two-dimensional plots of inverse mobility versus carbon number were created, with the double bond equivalents represented as the color of each point. Linear trends were observed for each of the four common molecular classes.After watching this video you should have a good understanding of the basic steps and unique advantages of APLI-TIMS-FT-ICR MS for the analysis of LEWAF samples as well as other complex mixtures. While attempting this procedure it's important to remember that sample integrity, such as reducing sources of contamination, is fundamental for accurate results. The characterization at the molecular level of the water-accommodated fractions of crude oils, the transformation products, and their fate during exposure to sunlight in the ocean is of the utmost environmental importance.Compared to other separation techniques such as liquid chromatography and gas chromatography, TIMS separation occurs in a shorter time scale, and is timing dependent, which permits better coupling with ultra high resolution MS analyzers while providing collision cross sections and chemical formulas in a single analysis. The generation of new comprehensive analytical tools for the analysis of complex mixtures at molecular level, such as TIMS-FT-ICR MS has great implications for our understanding of the chemical transformations and fate of crude oil in the ocean.

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Measurement of H2S in Crude Oil and Crude Oil Headspace Using Multidimensional Gas Chromatography, Deans Switching and Sulfur-selective Detection

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Recent soils research has shown that important chemical soil characteristics can change in less than a decade, often the result of broad environmental ...

Measurement of the Rheology of Crude Oil in Equilibrium with CO2 at Reservoir Conditions

A rheometer system to measure the rheology of crude oil in equilibrium with carbon dioxide (CO2) at high temperatures and pressures is described. The system comprises a high-pressure rheometer which is connected to a circulation loop. The rheometer has a rotational flow-through measurement cell with two alternative geometries: coaxial cylinder and double gap. The circulation loop contains a mixer, to bring the crude oil sample into equilibrium with CO2, and a gear pump that transports the mixture from the mixer to the rheometer and recycles it back to the mixer. The CO2 and crude oil are brought to equilibrium by stirring and circulation and the rheology of the saturated mixture is measured by the rheometer. The system is used to measure the rheological properties of Zuata crude oil (and its toluene dilution) in equilibrium with CO2 at elevated pressures up to 220 bar and a temperature of 50 &#176;C. The results show that CO2 addition changes the oil rheology significantly, initially reducing the viscosity as the CO2 pressure is increased and then increasing the viscosity above a threshold pressure. The non-Newtonian response of the crude is also seen to change with the addition of CO2.

Measurement of the Rheology of Crude Oil in Equilibrium with CO2 at Reservoir Conditions

A method for measuring the rheology of crude oil in equilibrium with carbon dioxide at reservoir conditions is presented.

A rheometer system to measure the rheology of crude oil in equilibrium with carbon dioxide (CO2) at high temperatures and pressures is described. The ...

Dispersion of Nanomaterials in Aqueous Media: Towards Protocol Optimization

The sonication process is commonly used for de-agglomerating and dispersing nanomaterials in aqueous based media, necessary to improve homogeneity and stability of the suspension. In this study, a systematic step-wise approach is carried out to identify optimal sonication conditions in order to achieve a stable dispersion. This approach has been adopted and shown to be suitable for several nanomaterials (cerium oxide, zinc oxide, and carbon nanotubes) dispersed in deionized (DI) water. However, with any change in either the nanomaterial type or dispersing medium, there needs to be optimization of the basic protocol by adjusting various factors such as sonication time, power, and sonicator type as well as temperature rise during the process. The approach records the dispersion process in detail. This is necessary to identify the time points as well as other above-mentioned conditions during the sonication process in which there may be undesirable changes, such as damage to the particle surface thus affecting surface properties. Our goal is to offer a harmonized approach that can control the quality of the final, produced dispersion. Such a guideline is instrumental in ensuring dispersion quality repeatability in the nanoscience community, particularly in the field of nanotoxicology.

Here, we present a step-wise protocol for the dispersion of nanomaterials in aqueous media with real-time characterization to identify the optimal sonication conditions, intensity, and duration for improved stability and uniformity of nanoparticle dispersions without impacting the sample integrity.

The sonication process is commonly used for de-agglomerating and dispersing nanomaterials in aqueous based media, necessary to improve homogeneity and ...

Microfluidic Devices for Characterizing Pore-scale Event Processes in Porous Media for Oil Recovery Applications

Microfluidic devices are versatile tools for studying transport processes at a microscopic scale. A demand exists for microfluidic devices that are resistant to low molecular-weight oil components, unlike traditional polydimethylsiloxane (PDMS) devices. Here, we demonstrate a facile method for making a device with this property, and we use the product of this protocol for examining the pore-scale mechanisms by which foam recovers crude oil. A pattern is first designed using computer-aided design (CAD) software and printed on a transparency with a high-resolution printer. This pattern is then transferred to a photoresist via a lithography procedure. PDMS is cast on the pattern, cured in an oven, and removed to obtain a mold. A thiol-ene crosslinking polymer, commonly used as an optical adhesive (OA), is then poured onto the mold and cured under UV light. The PDMS mold is peeled away from the optical adhesive cast. A glass substrate is then prepared, and the two halves of the device are bonded together. Optical adhesive-based devices are more robust than traditional PDMS microfluidic devices. The epoxy structure is resistant to swelling by many organic solvents, which opens new possibilities for experiments involving light organic liquids. Additionally, the surface wettability behavior of these devices is more stable than that of PDMS. The construction of optical adhesive microfluidic devices is simple, yet requires incrementally more effort than the making of PDMS-based devices. Also, though optical adhesive devices are stable in organic liquids, they may exhibit reduced bond-strength after a long time. Optical adhesive microfluidic devices can be made in geometries that act as 2-D micromodels for porous media. These devices are applied in the study of oil displacement to improve our understanding of the pore-scale mechanisms involved in enhanced oil recovery and aquifer remediation.

The goal of this procedure is to easily and rapidly produce a microfluidic device with customizable geometry and resistance to swelling by organic fluids for oil recovery studies. A polydimethylsiloxane mold is first generated, and then used to cast the epoxy-based device. A representative displacement study is reported.

Microfluidic devices are versatile tools for studying transport processes at a microscopic scale. A demand exists for microfluidic devices that are ...

The Effect of the Application of Thyme Essential Oil on Microbial Load During Meat Drying

Meat is a high protein meal that is used in the preparation of jerky, a popular food snack, where preservation and safety are important. To assure food safety and to extend the shelf life of meat and meat products, the use of either synthetic or natural preservatives have been applied to control and eliminate foodborne bacteria. A growing interest in the application of natural food additives for meat has increased. Microorganisms, such as Escherichia coli, contaminate meat and meat products, causing foodborne illnesses. Therefore, it is necessary to improve the meat conservation process. However, the use of essential oils when the meat is being dried has not been deeply studied. In this regard, there is an opportunity to increase the value of dried meat and reduce the risk of foodborne illnesses by applying essential oils during the drying process. In this protocol, we present a novel method of applying thyme essential oil (TEO) during meat drying, specifically in vapor form directly in a drying chamber. For evaluation, we use Minimal Inhibitory Concentration (MIC) to detect the number of harmful bacteria in the treated samples compared to raw samples. The preliminary results show that this method is a viable and alternative option to synthetic preservatives and that it significantly reduces microbial load in dried meat.

Microorganisms such as Escherichia coli that contaminate meat products cause foodborne illnesses. The use of essential oils in the meat drying process has not been deeply studied. Here, we present a novel method of applying thyme essential oil to meat during drying to reduce the microbial load in dried meat.

Meat is a high protein meal that is used in the preparation of jerky, a popular food snack, where preservation and safety are important. To assure food ...

Identification of Pharmaceuticals in The Aquatic Environment Using HPLC-ESI-Q-TOF-MS and Elimination of Erythromycin Through Photo-Induced Degradation

Monitoring pharmaceuticals throughout the water cycle is becoming increasingly important for the aquatic environment and eventually for human health. Targeted and non-targeted analysis are today's means of choice. Although targeted analysis usually conducted with the help of a triple quadrupole mass spectrometer may be more sensitive, only compounds previously selected can be identified. The most powerful non-targeted analysis is performed through time of flight mass spectrometers (TOF-MS) extended by a quadrupole mass analyzer (Q), as used in this study. Preceded by solid phase extraction and high-performance liquid chromatography (HPLC), the non-targeted approach allows to detect all ionizable substances with high sensitivity and selectivity. Taking full advantage of the Q-TOF-MS instrument, tandem mass spectrometry (MS/MS) experiments accelerate and facilitate the identification while a targeted MS method enhances the sensitivity but relies on reference standards for identification purposes. The identification of four pharmaceuticals from Rhine river water is demonstrated. The Rhine river originates in Tomasee, Graub&#252;nden, Switzerland and flows into the North Sea, near Southern Bight, The Netherlands. Its length amounts to 1232.7 km. Since it is of prime interest to effectively eliminate pharmaceuticals from the water cycle, the effect UV-C irradiation is demonstrated on a laboratory scale. This method allows fast degradation of pharmaceuticals, which is exemplarily shown for the macrolide antibiotic erythromycin. Using the above HPLC-Q-TOF-MS method, concentration-time diagrams are obtained for the parent drug and their photodegradation products. After establishing the equations for first-order sequential reactions, computational fitting allows the determination of kinetic parameters, which might help to predict irradiation times and conditions when potentially considered as fourth stage within wastewater treatment.

We present a protocol for non-targeted analysis using time of flight mass spectrometry as a perfect tool to identify pharmaceuticals in waters. We demonstrate the application of UV irradiation for their elimination. Analysis involving irradiation, compound isolation, identification and kinetic modelling of the degradation profiles is illustrated.

Monitoring pharmaceuticals throughout the water cycle is becoming increasingly important for the aquatic environment and eventually for human health. ...

A Novel Method for the Pentosan Analysis Present in Jute Biomass and Its Conversion into Sugar Monomers Using Acidic Ionic Liquid

Recently, ionic liquids (ILs) are used for biomass valorization into valuable chemicals because of their remarkable properties such as thermal stability, lower vapor pressure, non-flammability, higher heat capacity, and tunable solubility and acidity. Here, we demonstrate a method for the synthesis of C5 sugars (xylose and arabinose) from the pentosan present in jute biomass in a one-pot process by utilizing a catalytic amount of Br&#248;nsted acidic 1-methyl-3-(3-sulfopropyl)-imidazolium hydrogen sulfate IL. The acidic IL is synthesized in the lab and characterized using NMR spectroscopic techniques for understanding its purity. The various properties of BAIL are measured such as acid strength, thermal and hydrothermal stability, which showed that the catalyst is stable at a higher temperature (250 &#176;C) and possesses very high acid strength (Ho 1.57). The acidic IL converts over 90% of pentosan into sugars and furfural. Hence, the presenting method in this study can also be employed for the evaluation of pentosan concentration in other kinds of lignocellulosic biomass.

We present a protocol for the synthesis of C5 sugars (xylose and arabinose) from a renewable non-edible lignocellulosic biomass (i.e., jute) with the presence of Br&#248;nsted acidic ionic liquids (BAILs) as the catalyst in water. The BAILs catalyst exhibited better catalytic performance than conventional mineral acid catalysts (H2SO4 and HCl).

Recently, ionic liquids (ILs) are used for biomass valorization into valuable chemicals because of their remarkable properties such as thermal stability, ...

Isolation of Mandibular Gland Reservoir Contents from Bornean 'Exploding Ants' (Formicidae) for Volatilome Analysis by GC-MS and MetaboliteDetector

The aim of this manuscript is to present a protocol describing the metabolomic analysis of Bornean &#39;exploding ants&#39; belonging to the Colobopsis cylindrica (COCY) group. For this purpose, the model species C. explodens is used. Ants belonging to the minor worker caste possess distinctive hypertrophied mandibular glands (MGs). In territorial combat, they use the viscous contents of their enlarged mandibular gland reservoirs (MGRs) to kill rival arthropods in characteristic suicidal &#39;explosions&#39; by voluntary rupture of the gastral integument (autothysis). We show the dissection of worker ants of this species for the isolation of the gastral portion of the wax-like MGR contents as well as listing the necessary steps required for solvent-extraction of the therein contained volatile compounds with subsequent gas chromatography-mass spectrometry (GC-MS) analysis and putative identification of metabolites contained in the extract. The dissection procedure is performed under cooled conditions and without the use of any dissection buffer solution to minimize the changes in the chemical composition of the MGR contents. After solvent-based extraction of volatile metabolites contained therein, the necessary steps for analyzing the samples via liquid-injection-GC-MS are presented. Lastly, data processing and putative metabolite identification with the use of the open-source software MetaboliteDetector is shown. With this approach, the profiling and identification of volatile metabolites in MGRs of ants belonging to the COCY group via GC-MS and the MetaboliteDetector software become possible.

Isolation of Mandibular Gland Reservoir Contents from Bornean &#039;Exploding Ants&#039; Formicidae for Volatilome Analysis by GC-MS and MetaboliteDetector

Minor workers of the ant species Colobopsis explodens are dissected to isolate the wax-like content stored in their hypertrophied mandibular gland reservoirs for subsequent solvent-extraction and analysis by gas chromatography-mass spectrometry. The&#160;annotation and identification of volatile constituents using the open-source software MetaboliteDetector is also described.

The aim of this manuscript is to present a protocol describing the metabolomic analysis of Bornean &#39;exploding ants&#39; belonging to the Colobopsis ...