Jandyson M. Santos

Subcritical extraction of flaxseed oil with n-propane: Composition and purity

Flaxseed (Linum usitatissimum L.) oil was obtained via subcritical n-propane fluid extraction (SubFE) under different temperatures and pressures with an average yield of 28% and its composition, purity and oxidative stability were compared to oils obtained via conventional solvent extraction methods (SEMs). When the oxidative stability was measured by differential scanning calorimetry, the oil was found to be up to 5 times more resistant to lipid oxidation as compared to the SEM oils. Direct infusion electrospray ionization mass spectrometry (ESI-MS) analysis showed characteristic and similar TAG profiles for SubFE and SEMs oils but higher purity for the SubFE oil. The flaxseed oil content of β-tocopherol, campesterol, stigmasterol and sitosterol were quantified via GC-MS. SubFE showed to be a promising alternative to conventional SEM since SubFE provides an oil with higher purity and higher oxidation stability and with comparable levels of biologically active components.

Forensic Chemistry and Ambient Mass Spectrometry: A Perfect Couple Destined for a Happy Marriage?

Ambient mass spectrometry has been demonstrated, via various proof-of-concept studies, to offer a powerful, rather universal, simple, fast, nondestructive, and robust tool in forensic chemistry, producing reliable evidence at the molecular level. Its nearly nondestructive nature also preserves the sample for further inquiries. This feature article demonstrates the applicability of ambient mass spectrometry in forensic chemistry and explains the challenges that need to be overcome for this technique to make the ultimate step from the academic world into forensic institutes worldwide. We anticipate that the many beneficial and matching figures of merit will bring forensic chemistry and ambient mass spectrometry to a long-term relationship, which is likely to get strongly consolidated over the years.

Comprehensive characterization of lipids from Amazonian vegetable oils by mass spectrometry techniques

An integrative approach in mass spectrometry (MS) comprising gas chromatography coupled to MS (GC-MS), ultra-efficiency liquid chromatography coupled to MS (UPLC-MS) and easy ambient sonic-spray ionization MS (EASI-MS) is proposed for the comprehensive characterization of Amazonian oils. Coconut, andiroba and castor seed oils, which are vastly sold in markets of the Amazonian region of Brazil, were selected as a representative test set. These oils were found to contain several lipids such as triacylglycerides (TAGs), fatty acids (FAs), phytosterols and limonoids. In the analyzed samples 30 different TAGs, 11 FAs, 6 phytosterols and 7 limonoids were identified. The antioxidant capacity (AOC) of the oils, as measured by their oxygen radical absorbance capacity (ORAC), was also used to evaluate their potential biological properties as well as their possible consumption as food. Edible virgin coconut oil was the most active (0.720±0.001 Trolox eq./mmol), whereas considerable lower activity was observed for andiroba and castor seed oils. The antimicrobial activities of the oils were also recorded against a panel of pathogenic bacteria and fungi in which andiroba oil was the only one that was active, solely against Enterococcus aeruginosa.

Subcritical Extraction of Salvia hispanica L. Oil with N-Propane: Composition, Purity and Oxidation Stability as Compared to the Oils Obtained by Conventional Solvent Extraction Methods

This study evaluated the Chia (Salvia hispanica L.) oil composition in terms of fatty acids (FA), sterols, acylglycerols and oxidative stability obtained via subcritical n-propane fluid extraction (SubFE-propane), in different temperatures and pressure conditions, as compared to Bligh & Dyer (BD), Soxhlet (SE) and Folch (FLS) extractions. Total lipid varied from 23.25 to 30.21% and the best yield was obtained by both SubFE-propane extraction at 45 oC and 12 MPa (A). α-Linolenic acid (18:3n-3) was the most abundant FA and SubFE-propane extraction provided the best results for the sum of n-3 and PUFA. All oil samples were similar in regard to triacylglycerols (TAG) profiles as measured via direct electrospray ionization mass spectrometry (ESI-MS) analysis. The total amounts of stigmasterol, β-tocopherol and tocopherol total were highest in the Chia oil obtained by BD, campesterol and sitosterol by SE and γ-tocopherol by SubFE-propane extraction. The SubFE-propane oil also presented the best (2 to 5 times) oxidation stability. SubFE-propane was the most efficient extraction method for Chia oil, providing the highest extraction yields, purity, oxidation stability and diverse profile of sterols.

Petroleomics by ion mobility mass spectrometry: resolution and characterization of contaminants and additives in crude oils and petrofuels

Ion mobility-mass spectrometry (IM-MS), performed with exceptional resolution and sensitivity in a new uniform-field drift tube ion mobility quadrupole time-of-flight (IM-QTOF) instrument, is shown to provide a useful tool for resolving and characterizing crude oils and their contaminants, as well as petrofuels and their additives. Whereas direct analysis of a crude oil sample contaminated with demulsifiers by the classical ESI(±)-FTICR-MS petroleomic approach was unsatisfactory since it responds only with abundance and m/z, and ionization is impaired due to suppression of polar compounds of crude oil by additives likely used in petroleum industry, IM-MS enables mobility separation of ions, particularly of double bond equivalent (DBE) series for a giving CnX class providing separated spectra which are typical obtained either for the crude oil or the contaminants, even suffering of ion suppression or low ionization efficiency. The combination of improved IM resolution and high mass resolving power (40,000@400) of the QTOF instrument provides useful information on class (N, NO, NS, etc.), carbon number (Cn), and unsaturation (DBE) levels for crude oils, allowing one to infer geochemical properties from DBE trends that can be compared with IM-MS data. As demonstrated by results of gasoline samples with additives, the IM-MS system also allows efficient separation and characterization of additives and contaminants in petrofuels.

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.

Simple, Expendable, 3D-Printed Microfluidic Systems for Sample Preparation of Petroleum

In this study, we introduce a simple protocol to manufacture disposable, 3D-printed microfluidic systems for sample preparation of petroleum. This platform is produced with a consumer-grade 3D-printer, using fused deposition modeling. Successful incorporation of solid-phase extraction (SPE) to microchip was ensured by facile 3D element integration using proposed approach. This 3D-printed μSPE device was applied to challenging matrices in oil and gas industry, such as crude oil and oil-brine emulsions. Case studies investigated important limitations of nonsilicon and nonglass microchips, namely, resistance to nonpolar solvents and conservation of sample integrity. Microfluidic features remained fully functional even after prolonged exposure to nonpolar solvents (20 min). Also, 3D-printed μSPE devices enabled fast emulsion breaking and solvent deasphalting of petroleum, yielding high recovery values (98%) without compromising maltene integrity. Such finding was ascertained by high-resolution molecular analyses using comprehensive two-dimensional gas chromatography and gas chromatography/mass spectrometry by monitoring important biomarker classes, such as C10 demethylated terpanes, ααα-steranes, and monoaromatic steroids. 3D-Printed chips enabled faster and reliable preparation of maltenes by exhibiting a 10-fold reduction in sample processing time, compared to the reference method. Furthermore, polar (oxygen-, nitrogen-, and sulfur-containing) analytes found in low-concentrations were analyzed by Fourier transform ion cyclotron resonance mass spectrometry. Analysis results demonstrated that accurate characterization may be accomplished for most classes of polar compounds, except for asphaltenes, which exhibited lower recoveries (82%) due to irreversible adsorption to sorbent phase. Therefore, 3D-printing is a compelling alternative to existing microfabrication solutions, as robust devices were easy to prepare and operate.

A dopant for improved sensitivity in easy ambient sonic‐spray ionization mass spectrometry

Recently, 3-nitrobenzonitrile (3-NBN) has been used to improve sensitivity of sonic-spray ionization mass spectrometry. Easy ambient sonic-spray ionization (EASI) is one of the simplest, gentlest and most used spray-based desorption/ionization ambient techniques, but limited sensitivity has been commonly taken as its major drawback. Herein we investigate the use of 3-NBN as a dopant in EASI-MS for improved sensitivity. Using a few typical EASI samples as test cases, the presence of 10 ppm (µg ml(-1) ) of 3-NBN in the spray solvent showed two to fourfold gains in EASI-MS sensitivity as measured both by total ion current and S/N ratios, accompanied with significant reductions in chemical noise. Sensitivity for DESI using 3-NBN as a dopant also improved and dopant DESI versus dopant EASI sensitivities were compared. The use of solvent dopants seems therefore to be a promising strategy to improve sensitivity for spray-based ambient MS techniques. Copyright

Comprehensive Characterization of Second-Generation Biofuel from Invasive Freshwater Plants by FT-ICR MS

Ultra-high resolution and mass accuracy Fourier transform-ion cyclotron resonance mass spectrometry (FT-ICR MS) with an electrospray ionization source (ESI) was applied to characterize the bio-oils that were obtained using a micropyrolysis process of alternative biomasses from Eichornia crassipes (water hyacinth), Eichornia azurea, and Nymphaea ssp. The methods that have been developed for petroleomic analyses using FT-ICR MS data from crude oils and derivatives have been successfully employed herein to process such data for bio-oils, which are known as second-generation liquid biofuels. Class distributions and DBE versus carbon number plots (DBE × Cn) were, therefore, obtained. The class distribution for the oil obtained from water hyacinth was similar to those of classical bio-oils and appeared to be applicable as a fingerprint for bio-oils in general. The N2 and O2 classes obtained via ESI(+) and the O2 and O3 classes obtained via ESI(−) were the major classes detected in the bio-oil samples. In the DBE x Cn plot of the ESI(−)-FT-ICR MS data, the distribution of saturated and unsaturated fatty acids could be visualized, and characteristic profiles were determined for each bio-oil. It is, therefore, demonstrated that the FT-ICR MS methodology that is commonly applied to petroleomic studies can also be applied to biofuel characterization in a comprehensive “bio-oilomics” approach.

Forensic Application of X-ray Fluorescence Spectroscopy for the Discrimination of Authentic and Counterfeit Revenue Stamps

Energy-dispersive X-ray fluorescence (ED-XRF) spectroscopy with data treatment via chemometric tools was explored as an analytical protocol to discriminate between authentic and counterfeit revenue stamps. Untreated samples were directly analyzed, and the discrimination was based on the characterization of constituent elements present in the inks and paper. Authentic samples and samples that were suspected of being counterfeit were analyzed at three different areas on their surfaces: the ink-printed area, the non-printed area, and the holographic area. Principal component analysis (PCA) was applied to the data to discriminate between authentic and counterfeit revenue stamps. Major differences in the elemental composition were noted (according to chemometrics and t-test, p < 0.05), and ED-XRF spectroscopy plus PCA protocol is proposed for use by non-specialist operators to screen for counterfeit stamps.