Sonic-spray Ionization Mass Spectrometry Research Articles

Caffeine quantification in dietary supplements using high-throughput on-line solid phase extraction coupled to Venturi easy ambient sonic-spray ionization mass spectrometry.

Caffeine is present in a large number of beverages and is an additive used in dietary supplements. Therefore, the concern about its quality and safety for consumers has been increasing and hence requires faster and simpler analytical methods to determine the caffeine amount. The high-throughput analysis is an appropriate solution to pharmaceuticals, bioanalysis, forensic and food laboratory routines. In this sense, Venturi easy ambient sonic-spray ionization mass spectrometry (V-EASI-MS), a specific ambient ionization source, is suitable to enable direct analysis of sample solutions in real time and is appropriate to be coupled to liquid chromatography (LC). The development of an on-line solid phase extraction system coupled to V-EASI-MS optimizes the advantages of LC-MS hyphenation by enhancing the figures of merit of the analytical method according to AOAC guidelines and simultaneously minimizing the runtime analysis to 1.5 min per sample, as well as sample preparation steps and solvent consumption, which is currently a challenge for quantitative applications of ambient ionization MS.

Peroxides on the Surface of Organic Aerosol Particles Using Matrix-Assisted Ionization in Vacuum (MAIV) Mass Spectrometry.

Organic peroxides are key intermediates in the atmosphere but are challenging to detect, especially in the particle phase, due to their instability, which has led to substantial gaps in the understanding of their environmental effects. We demonstrate that matrix-assisted ionization in vacuum (MAIV) mass spectrometry (MS), which does not require an ionization source, enables in situ characterization of peroxides and other products in the surface layers of organic particles. Hydroxyl radical oxidation of glutaric acid particles yields hydroperoxides and organic peroxides, which were detected with signals of the same order of magnitude as the major, more stable products. Product identification is supported by MS/MS analysis, peroxide standards, and offline high-resolution MS. The peroxide signals relative to the stable carbonyl and alcohol products are significantly larger using MAIV compared to those in the offline bulk analysis. This is also the case for analysis using fast, online easy ambient sonic-spray ionization mass spectrometry. These studies demonstrate the advantage of MAIV for the real-time characterization of labile peroxides in the surface layers of solid particles. The presence of peroxides on the surface may be important for surface oxidation processes as well as for the toxicity of inhaled particles.

Interfacial Extraction to Trap and Characterize the Criegee Intermediates from Phospholipid Ozonolysis.

Criegee intermediates (CIs) play a significant role in cell membrane peroxidation, but their identification remains elusive at the molecular level. Herein, we combined interfacial extraction and sonic spray ionization mass spectrometry to study the oxidation reaction of 1-palmitoyl-2-oleoyl-sn-glycero-3-phospho-(1'-rac-glycerol) (POPG) mediated by ozone (O3) at/near the surface of a hung water droplet. On-line interfacial extraction and ionization provided a snapshot of the short-lived CIs. Experiments in which the content of water was varied provided evidence for the formation of CIs, which has not been previously observed. Capture experiments using 5,5-dimethyl-pyrroline N-oxide (DMPO) indicated that CIs could be selectively characterized, and the extracted ion current (EICs) of CIs vs DMPO-CI adducts further confirmed the successful observation of CIs. Theoretical calculation suggested that surface ozonolysis of POPG was mainly mediated by anti-CI. These results open a new route for aqueous surface reactive species identification, and benefit toward the understanding of disease development associated with cell oxidative stress mediated by CIs.

Rapid and direct detection of artificially aged papers employing easy ambient sonic-spray ionization mass spectrometry.

The effort to make fake documents look real leads to the use of crickets and beverages to produce artificially aged papers, as land titles, based on yellowing caused by the use of these methods. An old practice in Brazil, called "cricketing", has led to the misappropriation of Brazilian land using these documents. We propose a rapid, simple, instantaneous and non-destructive method to identify artificially aged papers by easy ambient sonic-spray ionization mass spectrometry (EASI-MS) analysis. Three typical aging procedures were used to obtain artificially aged papers using coffee, cola drink, and crickets, with the papers being analyzed by EASI-MS. Multivariate statistical analyses were performed on the data to find the sample groups and to study the most relevant ions of each ageing procedure. High-resolution MS (HRMS) was used to obtain the exact masses and attribute formulae to relevant ions present in the samples. The combination of EASI-MS and multivariate statistical analyses allowed us to identify the most relevant ions to classify the adulteration of documents and HRMS identified most of these relevant ions. TMS fingerprinting in combination with multivariate analysis also demonstrated that this approach can qualitatively differentiate all the examined paper samples. We developed a cheap, fast and easy method that can help to elucidate counterfeit documents that have been artificially aged, helping to identify chemical additives and one that can be used in forensic laboratories.

Improvement of lipid quality on nile tilapia fillet composition with low protein feeding treatment

The lipid composition is directly related to nutritious significance of fish meat. In this paper we evaluate the possibility of tuning lipid composition of Nile Tilapia fillet changing the feeding treatments with different levels of energy and protein using lipidomic approach. Five feeding treatments were used varying protein and energy content with soy protein, corn carbohydrates and soy oil. Easy Ambient Sonic-Spray Ionization mass spectrometry in negative mode was used for lipidomic characterization of polar lipids in Nile Tilapia fillet, that were extracted using the Bligh & Dyer method and evaluated by principal component analyzes revealing differences over the treatments. High Resolution Mass Spectrometry data obtained were imported into Lipid Maps (www.lipidmaps.org, accessed on 10/19/2018) for molecular identification. The major influence to separate the treatments was protein content, energy does not appear to differentiate the groups. Thirteen different ions were observed as the major differentiators of the groups and nine compounds were identified comparing the mass spectrometric results to Lipidomic library, and they are related to high metabolic activity, lipids with anti-diabetic effect, and fat levels reducers.

The effect of nitrogen starvation on membrane lipids of Synechocystis sp. PCC 6803 investigated by using easy ambient sonic-spray ionization mass spectrometry

BackgroundGlycerolipids are important components of membranes in cyanobacteria that possess vital roles in biological processes. The effect of nitrogen deprivation on membrane lipids of Synechocystis sp. PCC 6803 lipids has not been previously examined. MethodsEasy ambient sonic-spray ionization mass spectrometry (EASI-MS) was used for the analysis of Synechocystis 6803 cells with minimal sample preparation, providing rapid qualitative and relative quantitative information on the lipid content of their membranes. ResultsChanges in the degree of unsaturation of membrane lipids were observed for cells grown under normal conditions during different growth phases. This physiological remodeling was disrupted when nitrogen was withdrawn from the cultivation medium. However, this disruption was reversed when the cells were resuspended in normal N-containing medium. Mass spectrometric data were supported by examination of cells by electron microscopy. ConclusionsEASI-MS was applied for the first time in the analysis of Synechocystis 6803 cells grown under nitrogen deprived conditions and was found to be a powerful technique operating in a high-throughput manner for the rapid lipid profiling of cells at different growth stages and under different growth conditions. General significanceThe effect of nitrogen deprivation on membrane lipids of Synechocystis 6803 cells was revealed using an ambient ionization technique which enabled high-throughput cell analysis with minimal sample preparation. The results obtained have the potential to be used in future studies to decipher the involvement of enzymes in the observed lipid profile changes.

The impacts of the raising regime of Salmon species on their triacylglycerol composition revealed by easy ambient sonic-spray ionization mass spectrometry

Marine fish consumption is rising around the world due to the high quality of its nutritional components, including long chain polyunsaturated fatty acids (LC-PUFA), which are abundant and found as triacylglycerol (TAG) in the muscle and skin of Salmonidae family. Farm raised and wild species of Salmon have different diets, that directly influences their TAG composition. In this work, we demonstrate the evaluation of TAG composition of salmon species as an authenticity screening parameter. For this purpose, we propose the use of ambient mass spectrometry, here represented by the thermal imprinting (TI) easy ambient sonic-spray ionization mass spectrometry (EASI-MS), to offer a fast and ecofriendly method for TAG extraction and characterization of fish muscles and skins. Specifically, TI-EASI-MS was employed to obtain the TAG profiles of different species from Salmonids, which were compared using multivariate statistical analysis. Clear differentiation of wild-raised fishes was achieved based on their higher content of ions attributed to TAG containing PUFA when compared to farm-raised fishes. The TI extraction method was also compared to the standard Bligh & Dyer extraction protocol and the techniques were equivalent for Salmon species differentiation.

Progress of Sonic-Spray Ionization Mass Spectrometry and Its Applications

Abstract Sonic-spray ionization (SSI) is a previously developed soft ionization technique which does not need auxiliary methods such as voltage, heating, laser, or corona discharge. Spray ionization can be achieved under normal temperature and atmospheric pressure by inputting high-speed gas coaxial within the capillary. As an atmospheric pressure ion source, this technique was widely used as the interface of liquid chromatography-mass spectrometry at the beginning of its development. Based on the principles of sonic-spray ionization, a variety of easy ambient sonic-spray ionization derived techniques have been developed, which can be used for the in-situ, rapid and real-time analysis of samples with little or without any sample pretreatment. In this paper, the principless and characteristics of sonic-spray ionization were elaborated, and the progress of its application in life sciences, food safety, forensic chemistry, reaction monitoring, and other related fields were summarized.

Ambient mass spectrometry in foodomics studies

The current and future potential role of ambient mass spectrometry (AMS) in the fields of recently created discipline of foodomics is discussed. The main focus was set on the literature published between 2014 and 2018, although a few earlier papers of special interest have been included. Several examples for the successful application of AMS techniques including direct analysis in real time (DART), desorption electrospray ionization (DESI), easy ambient sonic spray ionization mass spectrometry (EASI-MS) and paper spray mass spectrometry (PS-MS) are presented.

Effect of Concentration on the Electrochemistry and Speciation of the Magnesium Aluminum Chloride Complex Electrolyte Solution.

Magnesium batteries offer an opportunity to use naturally abundant Mg and achieve large volumetric capacities reaching over four times that of conventional Li-based intercalation anodes. High volumetric capacity is enabled by the use of a Mg metal anode in which charge is stored via electrodeposition and stripping processes, however, electrolytes that support efficient Mg electrodeposition and stripping are few and are often prepared from highly reactive compounds. One interesting electrolyte solution that supports Mg deposition and stripping without the use of highly reactive reagents is the magnesium aluminum chloride complex (MACC) electrolyte. The MACC exhibits high Coulombic efficiencies and low deposition overpotentials following an electrolytic conditioning protocol that stabilizes species necessary for such behavior. Here, we discuss the effect of the MgCl2 and AlCl3 concentrations on the deposition overpotential, current density, and the conditioning process. Higher concentrations of MACC exhibit enhanced Mg electrodeposition current density and much faster conditioning. An increase in the salt concentrations causes a shift in the complex equilibria involving both cations. The conditioning process is strongly dependent on the concentration suggesting that the electrolyte is activated through a change in speciation of electrolyte complexes and is not simply due to the annihilation of electrolyte impurities. Additionally, the presence of the [Mg2(μ-Cl)3·6THF]+ in the electrolyte solution is again confirmed through careful analysis of experimental Raman spectra coupled with simulation and direct observation of the complex in sonic spray ionization mass spectrometry. Importantly, we suggest that the ∼210 cm-1 mode commonly observed in the Raman spectra of many Mg electrolytes is indicative of the C3v symmetric [Mg2(μ-Cl)3·6THF]+. The 210 cm-1 mode is present in many electrolytes containing MgCl2, so its assignment is of broad interest to the Mg electrolyte community.

Determination of chlorate, perchlorate and bromate anions in water samples by microbore reversed-phase liquid chromatography coupled to sonic-spray ionization mass spectrometry.

Sonic-spray ionization mass spectrometry (SSI-MS) has recently been shown to provide similar mass spectra to those generated by electrospray ionization mass spectrometry for a wide range of compounds, i.e. from small inorganic species to peptides, proteins and numerous other biomolecules. However, limited information about this new ionization technique, such as sensitivity, limit of detection and quantification accuracy, has been reported. In particular, its coupling to liquid chromatography needs further development and assessment, along with the introduction of a broad range of applications. A high-efficiency glass pneumatic nebulizer, used for decades for sample introduction in atomic spectrometry, was used for the SSI-MS analysis of chlorate (ClO3- ), perchlorate (ClO4- ) and bromate (BrO3- ) anions, following their separation using reversed-phase microbore high-performance liquid chromatography and tandem mass spectrometry (MS/MS) operated in selected reaction monitoring mode. The developed and optimized microbore HPLC/SSI-MS/MS technique exhibited low limits of detection: 5.3ng L-1 for chlorate, 10ng L-1 for perchlorate and 33.7ng L-1 for bromate, and provided reliable and accurate measurements of chlorate concentrations in water samples as demonstrated when comparing it with Ion Chromatography-Conductivity Detection (IC-CD), the benchmark technique for ion quantitation. This is the first time that the use of HPLC/SSI-MS/MS has been reported for the detection and quantitation of chlorate, perchlorate and bromate in water samples. In addition, the exceptionally low LODs achieved using SSI render the technique competitive with the established and dominating electrospray ionization technique. Here, we have demonstrated that a commercially available high-efficiency glass pneumatic nebulizer can also be used, without any further modification, as an efficient gas-phase ion source. Copyright © 2017 John Wiley & Sons, Ltd.

Incorporation of conjugated fatty acids into Nile tilapia (Oreochromis niloticus).

The aim of this work was to improve the nutritional quality of Nile tilapia meat through enriched diets with conjugated isomers of linolenic acid from tung oil. The transfer process of conjugated fatty acids (CFAs) into fish muscle tissue was evaluated by gas chromatography-flame ionization detection (GC-FID) and easy ambient sonic-spray ionization mass spectrometry (EASI-MS). The results showed that conjugated fatty acids were transferred from enriched diet for muscle tissue of Nile tilapia. Conjugated linoleic acids biosynthesis from conjugated linolenic acids was also observed after 10 days. Other important fatty acids such as docosahexaenoic (DHA), eicosapentaenoic (EPA) and arachidonic (AA) acids were also identified over time; however, DHA showed the highest concentration when compared with EPA and AA compounds. Therefore, the nutritional quality of Nile tilapia was improved through feeding with enriched diets. The ingestion of these fish may contribute to reaching adequate levels of daily CFA consumption. Furthermore, other important substances which play an important role in human metabolism, such as EPA, DHA and AA, can also be ingested together with CFA. © 2016 Society of Chemical Industry.

Easy ambient sonic-spray ionization mass spectrometry for tissue imaging

Easy ambient sonic-spray ionization mass spectrometry (EASI-MS) can be applied for tissue imaging when the application of high voltage is impractical or undesirable.

Elemental and molecular analysis of metal containing biomolecules using laser induced breakdown spectroscopy and sonic spray ionization mass spectrometry: A step towards full integration and simultaneous analysis

A novel methodology is proposed that combines sonic spray ionization (SSI) mass spectrometry (MS) with laser induced breakdown spectroscopy (LIBS) for analyzing metal-containing biomolecules and complexes. Focusing pulses from a nanosecond laser (Nd:YAG, λ=1064nm) in the microdroplet ensemble produced by a pneumatic nebulizer yielded LIBS spectra that enabled highly sensitive detection of several metal ions in aqueous and aqueous methanolic solutions. Based on the calibration curve method, LOD values at the ng/mL level were achieved for Ca (15ng/mL), Ba (27ng/mL), Cu (67ng/mL) and Fe (650ng/mL) with accuracy >90%. LIBS measurements were performed for the first time on aerosols of solutions of known biomolecules such as superoxide dismutase and alpha-lactalbumin, which led to the reliable determination of the concentration of Cu and Ca, respectively, both in the range of a few μg/mL. In parallel, the relative molecular mass of the metalloproteins was determined by separate SSI-MS measurements performed using an identical pneumatic nebulizer based sample introduction system. This is a first step towards the ultimate aim of integrating the two analytical techniques by use of a single pneumatic nebulization system for simultaneous sample introduction for both LIBS and SSI-MS. Such a system is expected to greatly enhance our capabilities to simultaneously acquire molecular and atomic data.

Synthesis of structured triacylglycerols enriched in n-3 fatty acids by immobilized microbial lipase.

The search for new biocatalysts has aroused great interest due to the variety of micro-organisms and their role as enzyme producers. Native lipases from Aspergillus niger and Rhizopus javanicus were used to enrich the n-3 long-chain polyunsaturated fatty acids content in the triacylglycerols of soybean oil by acidolysis with free fatty acids from sardine oil in solvent-free media. For the immobilization process, the best lipase/support ratios were 1:3 (w/w) for Aspergillus niger lipase and 1:5 (w/w) for Rhizopus javanicus lipase using Amberlite MB-1. Both lipases maintained constant activity for 6 months at 4 °C. Reaction time, sardine-free fatty acids:soybean oil mole ratio and initial water content of the lipase were investigated to determine their effects on n-3 long-chain polyunsaturated fatty acids incorporation into soybean oil. Structured triacylglycerols with 11.7 and 7.2% of eicosapentaenoic acid + docosahexaenoic acid were obtained using Aspergillus niger lipase and Rhizopus javanicus lipase, decreasing the n-6/n-3 fatty acids ratio of soybean oil (11:1 to 3.5:1 and 4.7:1, respectively). The best reaction conditions were: initial water content of lipase of 0.86% (w/w), sardine-free faty acids:soybean oil mole ratio of 3:1 and reaction time of 36 h, at 40 °C. The significant factors for the acidolysis reaction were the sardine-free fatty acids:soybean oil mole ratio and reaction time. The characterization of structured triacylglycerols was obtained using easy ambient sonic-spray ionization mass spectrometry. The enzymatic reaction led to the formation of many structured triacylglycerols containing eicosapentaenoic acid, docosahexaenoic acid or both polyunsaturated fatty acids.

Sacha inchi (Plukenetia volubilis L.) oil composition varies with changes in temperature and pressure in subcritical extraction with n-propane

Sacha inchi is an oilseed crop that shows high oil content and it is an excellent source of polyunsaturated fatty acids. Temperature and pressure can influence in lipid composition on the subcritical extraction with n-propane. The highest extraction yield obtained was 30% under the conditions of 60°C and 12MPa. The extracted oil presented 442mg of fatty acid g−1 in terms of alpha linolenic acid. Analysis by easy ambient sonic-spray ionization mass spectrometry showed a typical TAG (Triacylglycerols) profile for Sacha inchi oil with major ions of m/z (mass-to-charge ratio) 895 (ALA-ALA-ALA), 897 (ALA-ALA-LA), 899 (ALA-LA-LA) and 901 (LA-LA-LA or OL-LA-ALA) in a form of adduct of [TAG+Na]+, in which ALA is alfa linoleic acid, LA is linoleic acid and OL is oleic acid. The phytosterols content (86.39–101.92mg 100g−1 of total lipids) varied according to the conditions applied for the n-propane extraction. In general, the subcritical fluid extraction with n-propane was found to preserve the important Sacha inchi oil bioactive constituents, that is, fatty acids, triacylglycerols and phytosterols. Regression analysis also showed that higher temperatures and pressures result in higher yields of phytosterols.

A simpler sampling interface of venturi easy ambient sonic-spray ionization mass spectrometry for high-throughput screening enzyme inhibitors

High-throughput screening (HTS) is often required in enzyme inhibitor drugs screening. Mass spectrometry (MS) provides a powerful method for high-throughput screening enzyme inhibitors because its high speed, sensitivity and property of lable free. However, most of the MS methods need complicated sampling interface system. Overall throughput was limited by sample loading in these cases. In this study, we develop a simple interface which coupled droplet segmented system to a venturi easy ambient sonic-spray ionization mass spectrometer. It is fabricated by using a single capillary to act as both sampling probe and the emitter, which simplifies the construction, reduces the cost and shorten the sampling time. Samples sucked by venturi effect are segmented to nanoliter plugs by air, then the plugs can be detected by MS directly. This system eliminated the need for flow injection which was popular used in classic scheme. The new system is applied to screen angiotensin converting enzyme inhibitors. High-throughput was achieved in analyzing 96 samples at 1.6 s per sample. The plugs formation was at 0.5s per sample. Carry-over between samples was less than 5%, the peak height RSD was 2.92% (n = 15). Dose-response curves of 3 known inhibitors were also measured to validate its potential in drug discovery. The calculated IC50 agreed well with reported values.

Food quality and authenticity screening via easy ambient sonic-spray ionization mass spectrometry.

This review is the first to summarize a decade of studies testing the use of easy ambient sonic-spray ionization mass spectrometry (EASI-MS) and its several sister techniques, Venturi (V-EASI), thermal imprinting (TI-EASI) and Spartan (S-EASI) mass spectrometry in food quality control and authentication. Since minimal or no sample preparation is required, such ambient desorption/ionization techniques have been shown to provide direct, fast and selective fingerprinting characterization at the molecular level based on the pools of the most typical components. They have also been found to be applicable on intact, undisturbed samples or on simple solvent extracts. Fundamentals of EASI-MS and its sister techniques, including mechanisms, devices, parameters and strategies, as well as the many applications reported for food analysis, are summarized and discussed.

Immediate differentiation of unusual seed oils by easy ambient sonic-spray ionization mass spectrometry and chemometric analysis

We have applied the easy ambient sonic-spray ionization mass spectrometry technique to typification and differentiation of unusual vegetable seed oils.

Using the L/O ratio to determine blend composition in biodiesel by EASI-MS corroborated by GC-FID and GC-MS

Easy ambient sonic-spray ionization mass spectrometry (EASI-MS) is applied to the analysis of biodiesel blends prepared from soybean and animal fat biodiesel.