Easy Ambient Sonic-spray Ionization Mass 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.

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.

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.

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.

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.

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.

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.

Monitoring binding affinity between drug and α1-acid glycoprotein in real time by Venturi easy ambient sonic-spray ionization mass spectrometry

A new approach for monitoring the binding affinity between drugs and alpha 1-acid glycoprotein in real time was developed based on a combination of drug–protein reaction followed by Venturi easy ambient sonic-spray ionization mass spectrometry determination of the free drug concentrations. A known basic drug, propranolol was used to validate the new built method. Binding constant values calculated by venturi easy ambient sonic-spray ionization mass spectrometry was in good accordance with a traditional ultrafiltration combined with high performance liquid chromatography method. Then six types of basic drugs were used as the samples to conduct the real time analysis. Upon injection of alpha 1-acid glycoprotein to the drug mixture, the ion chromatograms were extracted to show the changes in the free drug concentrations in real time. By observing the drop-out of six types of drugs during the whole binding reaction, the binding affinities of different drugs were distinguished. A volume shift validating experiment and an injection delay correcting experiment were also performed to eliminate extraneous factors and verify the reliability of our experiment. Therefore, the features of Venturi easy ambient sonic-spray ionization mass spectrometry (V-EASI-MS) and the experimental results indicate that our technique is likely to become a powerful tool for monitoring drug–AGP binding affinity in real time.

Chemical Characterization of Jatropha curcas L. Seed Oil and Its Biodiesel by Ambient Desorption/Ionization Mass Spectrometry

Biodiesel has become increasingly attractive because of its environmental benefits and production from renewable resources. The use of Jatropha curcas L. oil as the feedstock for biodiesel production has attracted growing interest because it is a non-edible oil. Herein, easy ambient sonic-spray ionization mass spectrometry (EASI–MS) was used to chemically characterize, at the molecular level, J. curcas L. oil and its biodiesel via monitoring its triacylglycerols (TAG), free fatty acids (FFA), and profiles of fatty acid methyl esters (FAME). The results provide further support for those obtained by the standard parameters of fuel quality. The EASI–MS analysis described herein is simple, requires only a tiny droplet of the sample, and is conducted without any pre-separation or chemical manipulation steps.

Analysis of sexual assault evidence: statistical classification of condoms by ambient mass spectrometry.

Desorption electrospray ionization mass spectrometry (DESI-MS) and easy ambient sonic-spray ionization mass spectrometry (EASI-MS) are employed here in the forensic analysis of chemical compounds found in condoms and relative traces, and their analytical performances are compared. Statistical analysis of data obtained from mass spectra only was applied in order to obtain classification rules for distinguishing ten types of condoms. In particular, two supervised chemometric techniques [linear discriminant analysis (LDA) and soft independent modeling of class analogy (SIMCA)] were carried out on absolute and relative intensity values to test the performances of statistical models in terms of predictive capacity. The achieved classification of samples was excellent because of the high prediction percentages of the method used both for DESI and EASI mass spectrometry analyses, confirming these two as potential ambient ionization techniques for forensic analyses in case of sexual assault crimes. EASI-MS showed 99% prediction ability for LDA using relative data and 100% prediction ability for SIMCA using both absolute and relative ones, while DESI showed 94% prediction ability for both LDA and SIMCA. The absence of any sample preparation technique gives advantages in terms of sample preservation and reduced contamination, allowing successive analyses to be performed on the same sample by other techniques.

Characterization of ANFO explosive by high accuracy ESI(±)–FTMS with forensic identification on real samples by EASI(−)–MS

Ammonium nitrate fuel oil (ANFO) is an explosive used in many civil applications. In Brazil, ANFO has unfortunately also been used in criminal attacks, mainly in automated teller machine (ATM) explosions. In this paper, we describe a detailed characterization of the ANFO composition and its two main constituents (diesel and a nitrate explosive) using high resolution and accuracy mass spectrometry performed on an FT-ICR-mass spectrometer with electrospray ionization (ESI(±)–FTMS) in both the positive and negative ion modes. Via ESI(−)–MS, an ion marker for ANFO was characterized. Using a direct and simple ambient desorption/ionization technique, i.e., easy ambient sonic-spray ionization mass spectrometry (EASI–MS), in a simpler, lower accuracy but robust single quadrupole mass spectrometer, the ANFO ion marker was directly detected from the surface of banknotes collected from ATM explosion theft.

Study on variation of lipids during different growth phases of living cyanobacteria using easy ambient sonic-spray ionization mass spectrometry.

Lipids are important components of cell membranes and thylakoids in cyanobacteria, and they play vital roles in various biological activities. Real-time tracing of the variation of membrane lipids can provide insights of the physiological status of cyanobacterial cells. In this work, easy ambient sonic-spray ionization mass spectrometry (EASI-MS) was utilized to investigate the changes of acidic lipids in unicellular (Synechocystis 6803, Synechococcus 7002) and filamentous (Anabaena 7120) cyanobacteria during different growth phases. A sqdX mutant with a reduced synthesis of sulfoquinovosyl diacylglycerol (SQDG) was constructed to verify the acquired data of EASI-MS. Principal component analysis (PCA) was performed to compare the acquired data, enabling the discrimination of different species of cyanobacteria in day-to-day analysis. The results showed that the three representative cyanobacteria and their growth status can be easily determined on the basis of the lipids components detected by EASI-MS. Very interestingly, significant decreases of the ratios of SQDG/PG and dramatic changes of the unsaturation level of lipids were observed in different culture times in these cyanobacteria, and these two unique characters can be used describe the aging of cyanobacteria.

Real-time analysis of self-assembled nucleobases by Venturi easy ambient sonic-spray ionization mass spectrometry

In this study, the real-time analysis of self-assembled nucleobases was employed by Venturi easy ambient sonic-spray ionization mass spectrometry (V-EASI-MS). With the analysis of three nucleobases including 6-methyluracil (6MU), uracil (U) and thymine (T) as examples, different orders of clusters centered with different metal ions were recorded in both positive and negative modes. Compared with the results obtained by traditional electrospray ionization mass spectrometry (ESI-MS) under the same condition, more clusters with high orders, such as [6MU7+Na]+, [6MU15+2NH4]2+, [6MU10+Na]+, [T7+Na]+, and [T15+2NH4]2+ were detected by V-EASI-MS, which demonstrated the soft ionization ability of V-EASI for studying the non-covalent interaction in a self-assembly process. Furthermore, with the injection of K+ to the system by a syringe pumping, the real-time monitoring of the formation of nucleobases clusters was achieved by the direct extraction of samples from the system under the Venturi effect. Therefore, the effect of cations on the formation of clusters during self-assembly of nucleobases was demonstrated, which was in accordance with the reports. Free of high voltage, heating or radiation during the ionization, this technique is much soft and suitable for obtaining the real-time information of the self-assembly system, which also makes it quite convenient for extraction samples from the reaction system. This “easy and soft” ionization technique has provided a potential pathway for monitoring and controlling the self-assembly processes.