Search

A direct, rapid, and convenient method for the determination of iodine value (IV) of biodiesels from vegetable oils has been developed by the application of nuclear magnetic resonance (500 and 600 MHz 1H NMR) techniques. The method is based on the correlation of integrated intensities (Ius) of unsaturated hydrogen in the 1H NMR spectra of biodiesels with (1) the predetermined iodine values by the standard iodometry based method (EN 14111), (2) iodine values determined from the fatty acid profile by GC-MS method, and (3) iodine values from the absolute number of double bonds (ADB) determined by 1H NMR. The simple mathematical equation, IV = K(Ius) (K = 15.78), derived from the correlations, provides a direct method for the determination of iodine value in the range of 5–140 g of I2/(100 g). The constant “K” has been found to be independent of the nature and source of vegetable oils. It is equally applicable to blends of biodiesels, blends of biodiesel and oils in all proportions, and biodiesel samples cont...

Rationale Brazil is the largest producer of sugar cane bioethanol in the world. Isotope ratio mass spectrometry (IRMS) is the technique of choice to certify the origin/raw materials for ethanol production, but the lack of certified reference materials (CRMs) for accurate measurements of δ13C values traceable to Vienna Pee Dee Belemnite (VPDB), the international zero point for 13C/12C measurements, certified and compatible with gas chromatography (GC)/IRMS instruments may compromise the accuracy of δ13C determinations. Methods We evaluated the influence of methods for the calibration and normalization of raw δ13C values of ethanol samples. Samples were analyzed by GC/C/IRMS using two different GC columns. Different substances were used as isotopic standards for the working gas calibration. The δ13C values obtained with the three methods of normalization were statistically compared with those obtained with elemental analyzer (EA)/IRMS, since the δ13C results obtained using EA are traceable to VPDB via the NBS 22 reference material. Results It was observed that both the isotopic reference material for CO2 calibration and the GC column have a major effect on the δ13C measurements, leading to a bias of almost 2–3 ‰ in the δ13C values. All three methods of normalization were equivalent in performance, enabling an improvement in the GC/C/IRMS accuracy, compared with the EA/IRMS reference values for the samples. Conclusions All the methods of CO2 calibration, chromatography and normalization presented in this work demonstrated several sources of traceability and accuracy loss for the determination of δ13C values in ethanol fuel samples by GC/C/IRMS. This work has also shown the importance of using proper CRMs traceable to VPBD that should be compatible and certified using GC/C/IRMS, ideally in a wide range of δ13C values. This is important not only for bioethanol fuel samples, but also for many analytes commonly analyzed by IRMS. Copyright © 2015 John Wiley & Sons, Ltd.

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.

To address the title question, the relative intrinsic acidities of phenol and benzoic acid as well as the isomeric family of ortho-, meta-, and para-hydroxybenzoic acids were compared. Dissociation of the [PhCO2···H···OPh]– proton-bound dimer showed slightly greater acidity for benzoic acid. Using traveling-wave ion mobility mass spectrometry (TWIM-MS) with CO2 as the drift gas and post-TWIM collision-induced dissociation, the gaseous deprotonated molecules of the isomeric hydroxybenzoic acids were properly separated and characterized. For the para isomer, an intrinsic gas-phase acidity order inverse to that in solution was found, as before, that is, the phenol site of para-hydroxybenzoic acid was found to be considerably more acidic than its benzoic acid site, whereas the opposite was observed in solution, regardless of the solvent. However, for the ortho and meta isomers, the inversion in acidity order upon going from solution to the gas phase was not observed, and gaseous carboxylate anions were still found to predominate over phenoxide anions. Actually, for the ortho isomer, an even greater acidity as estimated from proton affinity values for the benzoic acid site relative to that of the phenol site was predicted, and accordingly, only a single isomer was sampled by TWIM-MS. Rationales for these contrasting trends based on interfering inductive effects, charge delocalization by resonance, and intraionic H-bonds that govern the acidity of benzoic acid relative to that of phenols are presented.

Ethanol has been increasingly used worldwide as a major renewable fuel. Since it can be produced from several matrixes such as sugarcane, corn, wheat, grape and beet, it has become important for certification purposes to verify the geographical origin and the different raw materials used for ethanol production. In this work, isotope ratio mass spectrometry, coupled to gas chromatography, was used to measure the carbon isotopic signature (δ13CV-PDB) of Brazilian sugar cane bioethanol. Statistical data analysis was also applied to establish a probabilistic profile for the isotopic signature of major renewable Brazilian fuel. Other bioethanol samples produced from different raw materials in the USA and France were also analysed, for comparison.

The harvesting of Brazilian mahogany (Swietenia macrophylla) is a main cause of the Brazilian Amazon deforestation and has been therefore prohibited. African mahogany (Khaya ivorensis) was then introduced for Amazon reforestation and the commercialization of such wood is legal, thus creating a challenging problem for wood certification. Herein we report that a wood chemotaxonomic method based on distinct profiles of phytochemical markers is able to promptly characterize both the native and foreign mahogany species. This challenging task has been performed via a simple, fast and unambiguous methodology using direct electrospray ionization mass spectrometry (ESI-MS) analysis of a simple methanolic extract of a tiny wood chip. Typical limonoids such as khivorin, khayanolide A and mexicanolide for African mahogany and phragmalin-type limonoids for the native Brazilian species, as well as distinct polyphenols such as catechin derivatives and cinchonain, form the characteristic phytochemical marker pools for both species. This rapid methodology could therefore be used to monitor legal and illegal mahogany tree harvesting, and hence to control Amazon deforestation. It could also be applied to create a wood certification program for African and Brazilian mahogany trees, as well as for wood certification in general.

Using a non-natural fatty acid methyl ester (FAME) as an internal standard we evaluated the ability of easy ambient sonic-spray ionization mass spectrometry (EASI-MS) to quantitate the unsaturated FAME levels in B100 biodiesel from soybean, canola and Jatropha curcas. The ability of EASI(+)-MS to discriminate between saturated versus unsaturated FAME was also evaluated. Calibration curves for the major FAME, those from linolenic, linoleic and oleic acids, showed good linearity with coefficient correlation > 0.99 with the EASI(+)-MS method. The spike recoveries ranged from 76% to 127% with good repeatability and reproducibility as indicated by the relative standard deviation (RSD), which ranged from 5.1% to 17.7%. The accuracy of the method was established using a standard reference material (SRM). Real biodiesel samples were also quantitated via EASI(+)-MS, and the unsaturated FAME content was found to correlate adequately with the data obtained from the iodine number. Therefore, EASI(+)-MS was shown to provide fast, direct, linear and accurate quantitation of the unsaturated FAME in biodiesel samples. (C) 2014 Elsevier Ltd. All rights reserved.

Analytical strategies based on NMR (1H and 13C), IR (infrared), and GC (gas chromatography) techniques have been developed for the molecular level characterization of Soxhlet and ultrasonic solvent extracts of yeast biomass samples generated on a lab scale by different yeast, feed, and diverse culture conditions, with an objective to explore biodiesel potential. The extraction efficiency of each solvent (cyclohexane, chloroform, methanol) toward extraction of neutral lipids (total glycerides (TG), free fatty acids (FFA), and polar lipids have been determined and compared with regards to the nature of fatty acid components extracted in each solvent fractions. The fatty acid composition of yeast extracts has been found to be similar to vegetable oils, mostly rich in C16:0, 18:0, and C18:N (N = 1–3) fatty acids as indicated by the combined NMR, GC, and GC-MS analyses. The analytical protocol developed has established that 1H NMR techniques can be used directly and rapidly without any sample treatment and pri...

The technique of choice for petroleomics has been ultra-high-resolution and high-accuracy Fourier transform ion cyclotron resonance mass spectrometry (FT-ICR MS), but other techniques such as ion mobility have been shown to provide additional or alternative information about crude oil composition. Using the traveling wave ion mobility (TWIM) cell of a hybrid Q-TWIM-TOF first-generation Synapt instrument and electrospray ionization in both the positive and negative ion modes, different crude oil samples with different polar compound profiles and petro fuels (diesel and gasoline) with or without additives were analyzed using either CO2 or N2 as the drift gas. Parameters such as gas pressure, velocity, and wave height were optimized for each type of crude oil or fuel sample. The ability of TWIM–MS to separate crude oil components according to their classes was verified by comparison with FT-ICR data. Results showed separation of several classes of polar compounds (NO, O2, and N), and their separation was imp...

Biodiesel is a renewable source of global interest and one of the most attractive alternatives to partially replace petroleum fuels. Because of its chemical nature, however, biodiesel quality may be more rapidly degraded (than hydrocarbon-based fossil fuels) because of oxidation particularly during long or inappropriate storage. Herein, we show that a direct, rapid, and easy to implement and perform technique, that is, easy ambient sonic-spray ionization mass spectrometry (EASI–MS), can be successfully applied to monitor biodiesel oxidation. Soybean biodiesel stored under different conditions has been monitored by EASI–MS, and markers of oxidation have been identified. A new oxidation index (Iox) rapidly and easily determined via EASI–MS was proposed.

Ion mobility mass spectrometry performed in a compact traveling wave cell (TWIM-MS) is shown to provide a reliable, fast and repeatable method to separate derivatized steroid isomers. Three steroid isomer pairs were analyzed in their native form and as their p -toluenesulfonyl isocyanate derivatives. The native steroids were separated from each other, but no separation could be attained for the isomers. The derivatized steroid isomers were, however, properly separated by TWIM-MS with peak-to-peak resolutions close to or as high as baseline resolution ( R p − p = 0.77–1.08).

We have studied the behavior of isomers and analogues by traveling wave ion mobility mass spectrometry (TWIM-MS) using drift-gases with varying masses and polarizabilities. Despite the reduced length of the cell (18 cm), a pair of constitutional isomers, N-butylaniline and para-butylaniline, with theoretical collision cross-section values in helium (ΩHe) differing by as little as 1.2 A2 (1.5%) but possessing contrasting charge distribution, showed baseline peak-to-peak resolution (Rp-p) for their protonated molecules, using carbon dioxide (CO2), nitrous oxide (N2O) and ethene (C2H4) as the TWIM drift-gas. Near baseline Rp-p was also obtained in CO2 for a group of protonated haloanilines (para-chloroaniline, para-bromoaniline and para-iodoaniline) which display contrasting masses and theoretical ΩHe, which differ by as much as 15.7 A2 (19.5%) but similar charge distributions. The deprotonated isomeric pair of trans-oleic acid and cis-oleic acid possessing nearly identical theoretical ΩHe and ΩN2 as well as similar charge distributions, remained unresolved. Interestingly, an inversion of drift-times were observed for the 1,3-dialkylimidazolium ions when comparing He, N2 and N2O. Using density functional theory as a means of examining the ions electronic structure, and He and N2-based trajectory method algorithm, we discuss the effect of the long-range charge induced dipole attractive and short-range Van der Waals forces involved in the TWIM separation in drift-gases of differing polarizabilities. We therefore propose that examining the electronic structure of the ions under investigation may potentially indicate whether the use of more polarizable drift-gases could improve separation and the overall success of TWIM-MS analysis. Copyright © 2013 John Wiley & Sons, Ltd.

Ion mobility spectrometry (IMS) separates ions while they travel through a buffer gas under the influence of an electrical field. The separation is affected by mass and charge but most particularly by shape (collision cross section). When coupled to MS, IMS-MS offers therefore a powerful tool for structural elucidation and isomer separation. Systematic studies aimed to compare and quantitate the effects of structural changes on drift time such as length and ramification of carbon chain, unsaturation, geometrical isomerism (cis/trans isomers for instance), cyclization and ring size are, however, scarce. Herein we used traveling wave ion mobility mass spectrometry (TWIM-MS) to systematically evaluate the relationship between structure and drift time. For that, a series of deprotonated carboxylic acids were used as model ions with a carboxylate “charge tag” for gas phase MS manipulation. Carboxylic acids showed a near linear correlation between the increase of carbon number and the increase of collision cross section (CCS). The number of double bonds changes slightly the CCS of unsaturated acids. No differences in drift time and no significant differences in CCS of cis- and trans-double bond of oleic and elaidic acids were observed. Cyclization considerably reduces the CCS. In cyclic carboxylic acids, the increase of double bonds and aromatization significantly reduces the CCS and the drift times. The use of a more polarizable drift gas, CO2, improved in some cases the separation, as for biomarker isomers of steranoic acids. The β-isomer (cis-decaline) has smaller CCS and therefore displayed lower drift time compared to the α-isomer (trans-decaline). Structural changes revealed by calculations were correlated with trends in drift times.

Biodiesel is the main partial substitute for petrodiesel. Some biodiesels have low oxidative stability. To solve or minimize this problem, some compounds have been added to biodiesel as antioxidants. One of the most efficient classes of compounds used for this is aromatic diamines because of their high antioxidant capacity at low concentration. Aromatic diamines can be used as artificial markers. It is sometimes necessary to determine the concentration of antioxidants in biodiesel after long storage times or to control quality. An easy to use spectrophotometric methodology was employed in this work to determine the concentration of aromatic diamines (0 to 500 ppm). Five calibration curves were constructed using 3 absorption frequencies from the infrared spectra of the samples. The standard deviation, correlation coefficient, linearity range, limit of detection and limit of quantification were determined. The better results from the easy to use method (814 cm − 1 ) show a linear range of 0–100 ppm with a strong correlation (R2 = 0.9966) and a limit of quantification of 21.6 ppm.

The main objective of the reference materials for biofuel specifications (BIOREMA) project is the development of two test materials (one bio-ethanol material and one biodiesel material) with well-established reference values. Of a series of three papers, this part describes the material preparation, homogeneity study, stability study, and characterisation of the bio-ethanol material. The test material thus obtained was used in an interlaboratory comparison (ILC) to assess current practices and comparability amongst laboratories providing bio-ethanol testing services. Only 13 participants provided data, resulting in a small dataset for evaluation. Further, it appeared that for a number of laboratories, there was not sufficient material for the determination of all requested parameters. In most cases, as far as the data permit, it can be concluded that the consensus values (based on participant’s results) are in good agreement with the reference or the BIOREMA values (obtained by NMIs participating in the project). For three parameters, namely ethanol content, water content, and density, there is good agreement between the reference and consensus values. For these parameters, the reproducibility standard deviation is close to, or even smaller than, the expanded uncertainty associated with the reference value. A number of parameters show very poor reproducibility, for example, pHe, electrolytic conductivity, and acidity. The same applies to sodium and copper content, which are very low and therefore challenging parameters to measure accurately. The results of the ILC underpin the need for certified reference materials and demonstrate the requirement for more robust quality control to improve the precision and trueness of the results from testing laboratories.

Analytical strategies based on Nuclear Magnetic Resonance (NMR) (500 MHz and 800 MHz) spectroscopic techniques (1H, 13C, 13C-DEPT) have been presented for monitoring the development of Certified Reference Material (CRM) of biodiesel meeting ASTM D 6751/EN 14214 specifications. The protocol includes the analyses of feedstocks of oil and biodiesel, and impurities generated during transesterification reaction by NMR methods duly validated by standard methods based on GC-MS. The quality parameters such as contents of ester (B100), linolenic acid (C18:3), poly unsaturated fatty acids (PUFA), residual acyl glycerides (mono, di, tri), free glycerin and fatty acid profile, and iodine values have been determined directly by newly developed methods based on NMR techniques in samples of biodiesel produced by transesterification reaction of soybean, sunflower, cotton, canola and corn (maize) oils drawn at different interval of times. The systematic 1H and 13C NMR spectral interpretation has revealed the presence of five types of residual glycerides (AGs) namely 1 or 2 mono glycerides (1-MG, 2-MG); 1,2 and 1,3 di glycerides (1,2-DG; 1,3-DG) and tri glyceride (1,2,3-TG) in the biodiesel as well as transesterified products independent of types and nature of vegetable oils. The spectral analyses of samples at 800 MHz NMR instrument has provided enhanced sensitivity and resolution of signals of interest, which enabled identification of very low levels of various AGs. The repeatability of standard Deviation (%SD) of quality parameters show that the NMR methods provide results with acceptable precision. The accurate and rapid profiling of residual impurities generated during transesterification reaction without any further chemical treatment will be an effective guide for the catalyst developer for the syntheses of novel catalysts required for quality control of biodiesel. A rapid and convenient approach has been described for the analyses and quantification of bound and free glycerin in the biodiesel and transesterified products, which will enable rapid quality assessment and certification of CRMs.

The detailed component analyses of algal oils such as neutral (mono, di and triglycerides; free fatty acids) and polar (glyceroglyco/phospho) lipids, and their fatty acid profile including poly unsaturated fatty acids (PUFAs) (C18:3, C22:6) have been carried out by NMR (1H, 13C) and GC-MS techniques to explore their biodiesel potential. The algal oils were obtained by ultrasonic solvent extraction of microalgae biomasses cultivated on a lab scale. The results revealed that biomass and neutral lipids productivity as well as quality and composition of saturated and unsaturated fatty acid were influenced by media (modified RM6, F/2, WC), microalgae species/strains (Chlorella vulgaris, Spirulina platensi and Tetraselmis affchuii) and shape of the cultivated system (Erlenmeyer flask, polythene tubular or round container). The replacement of source of N and P with cheaper source of fertilizers (super phosphates + Chillean salt peter) in the cultivation media F/2 and WC has not affected the neutral lipid productivity, rather produced FAMEs with lower amount of Docosahexaenoic acid (DHA). The biomass cultivated in the modified RM6 media by Spirulina platensi is comprised of lower amount of unsaturated fatty esters without DHA (42.9% w/w) (PUFA as E¤-linoleic) compared to other biomasses (61.2-69.8 %w/w), thus quite suitable for production of biodiesel with higher oxidation stability and higher cetane number. The algal oils generated from the biomasses in the cultivation system are promising feed stocks for biodiesel and value added products DHA and α, γ -linolenic acids. The developed fast and cost effective analytical strategy based on 1H NMR techniques will facilitate algae cultivators for screening of species and optimization of cultivation parameters to produce a choice of product, thus contribute partly in the overall reduction in the cost of production of biodiesel.

There is an increasing demand to accurately measure the quality of biofuel products (e.g. biodiesel and bio-ethanol). This demand is driven in Europe by directives promoting the use of renewable sources of energy and worldwide by national and international legislation setting out quality requirements for these fuels. Until now, there has been no international consensus on the minimum technical specifications to ensure biofuel quality. Furthermore, it is unclear which reference materials and measurement techniques are needed to provide the quality assurance and quality control framework to underpin these legislative requirements. As part of the European Commission’s 7th Framework Programme, the BIOREMA project (REference MAterials for BIOfuel specifications) demonstrated the feasibility of preparing biodiesel and bio-ethanol reference materials with reference values traceable to the international system of units for a range of parameters at levels relevant to technical specifications. However, the project concluded also that further research is needed to improve the current measurement capabilities for some parameters. Within the BIOREMA project, two global interlaboratory comparisons were carried out, using the biodiesel and bio-ethanol test materials prepared during the feasibility stage of the project, as well as two biodiesel standard reference materials from the National Institute of Standards and Technology (NIST, USA). The exercises showed that the measurement capabilities of the field laboratories were in many cases satisfactory, whereas for other laboratories the availability and regular use of certified reference materials would likely enhance the measurement capabilities for many of the parameters studied. A general overview of the BIOREMA project is presented in this paper. The details of the production of the two types of BIOREMA reference materials, and the results of the interlaboratory comparison for the bio-ethanol and biodiesel study materials, are discussed in parts 2 and 3 of this series of papers.

The use of CO2 as a massive and polarizable drift gas is shown to greatly improve peak-to-peak resolution (Rp-p), as compared with N2, for the separation of disaccharides in a Synapt G2 traveling wave ion mobility cell. Near or baseline Rp-p was achieved for three pairs of sodiated molecules of disaccharide isomers, that is, cellobiose and sucrose (Rp-p = 0.76), maltose and sucrose (Rp-p = 1.04), and maltose and lactose (Rp-p = 0.74). Ion mobility mass spectrometry using CO2 as the drift gas offers therefore an attractive alternative for fast and efficient separation of isomeric disaccharides. Copyright © 2012 John Wiley & Sons, Ltd.

Easy sonic-spray ionization mass spectrometry (EASI–MS) allows for direct and fast MS analysis of samples in ambient conditions with little or no sample preparation, therefore offering unprecedented simplicity, speed, and ease of use. EASI–MS has been shown to access the quality, type, and adulteration of biofuels and vegetable oils. Herein, EASI–MS is shown to quantitate and monitor the quality of soybean biodiesel/petrodiesel (Bn) blends. For adulteration, admixture of the parent oil has been tested and nearly instantaneous and direct EASI(+)–MS detection of as little as 1% (w/w) of soybean oil in biodiesel/petrodiesel blends was achieved. Linear analytical curves (r > 0.98) were also obtained for the quantitation of Bn blends, and the EASI(+)–MS quantitation results were compared to those obtained by nuclear magnetic resonance (NMR) spectroscopy and mid-infrared (IR) spectroscopy.

Travelling wave ion mobility mass spectrometry (TWIM-MS) with post-TWIM and pre-TWIM collision-induced dissociation (CID) experiments were used to form, separate and characterize protomers sampled directly from solutions or generated in the gas phase via CID. When in solution equilibria, these species were transferred to the gas phase via electrospray ionization, and then separated by TWIM-MS. CID performed after TWIM separation (post-TWIM) allowed the characterization of both protomers via structurally diagnostic fragments. Protonated aniline (1) sampled from solution was found to be constituted of a ca. 5:1 mixture of two gaseous protomers, that is, the N-protonated (1a) and ring protonated (1b) molecules, respectively. When dissociated, 1a nearly exclusively loses NH(3) , whereas 1b displays a much diverse set of fragments. When formed via CID, varying populations of 1a and 1b were detected. Two co-existing protomers of two isomeric porphyrins were also separated and characterized via post-TWIM CID. A deprotonated porphyrin sampled from a basic methanolic solution was found to be constituted predominantly of the protomer arising from deprotonation at the carboxyl group, which dissociates promptly by CO(2) loss, but a CID-resistant protomer arising from deprotonation at a porphyrinic ring NH was also detected and characterized. The doubly deprotonated porphyrin was found to be constituted predominantly of a single protomer arising from deprotonation of two carboxyl groups.

Used frying oil seems to be an economically viable and environmentally attractive alternative for biodiesel production, but the acceptance and successful use of this and other biodiesels obtained from waste materials require careful evaluation of its fuel properties and impurities. Herein, we show that biodiesel made from used frying soybean oil display overall quality comparable to those obtained from the fresh oil as measured by standard parameters of fuel quality such as induction period, acid number, heat of combustion, and iodine value as well as at the molecular level via profiles of intact and oxidized fatty acid methyl esters. These profiles were obtained directly from the biodiesel samples by easy ambient sonic spray ionization mass spectrometry. An artificial antioxidant, N,N′-di-sec-butyl-p-phenylenediamine, was shown to significantly increase the oxidative stability of the used frying oil biodiesel at trace level.

The ability of travelling wave ion mobility mass spectrometry (TWIM-MS) to resolve cationic meta/para and cis/trans isomers of mono-, di-, tri- and tetra-ruthenated supramolecular porphyrins was investigated. All meta isomers were found to be more compact than the para isomers and therefore mixtures of all isomeric pairs could be properly resolved with baseline or close to baseline peak-to-peak resolution (Rp-p). Di-substituted cis/trans isomers were found, however, to present very similar drift times and could not be resolved. N2 and CO2 were tested as the drift gas, and similar α but considerably better values of Rp and Rp-p were always observed for CO2. Copyright © 2012 John Wiley & Sons, Ltd.

Venturi easy ambient sonic spray ionization mass spectrometry in both itsliquid(VL-EASI-MS) and solid sample modes (VS-EASI-MS) is shown to provide nearly immediate and secure typification of woods, as demonstrated for Mahogany, an endangered and mostvaluabletypeoftropical wood. Thisreddishwood displaysuniquephytochemical markers(phragmalin-typelimonoids) which are rapidly detected from the wood surface by VS-EASI-MS or from a simple methanol extract of a tiny wood chip by VL-EASI-MS. Unique profiles were obtained for Mahogany (Swietenia macrophylla) whereas genuine samples of six other similar types of woods, which are commonly falsified by artificial coloring and commercialized as Mahogany, display also typical but dissimilar pythochemical profiles as compared to that of the authentic wood. Variable and atypical chemical profiles were observed for artificially colored woods. Secure chemical characterization via VS-EASI-MS or Vs-EASI-MS fingerprints of Mahogany and other types of woods with similar appearance should help to control the illegal logging and trade of this and other endangered woods and their falsification, and to create certified standards. Copyright © 2012 John Wiley & Sons, Ltd.

Biodiesel is composed of saturated and unsaturated methyl esters of fatty acids formed via transesterification of vegetable oil or animal fat. This chemical nature makes biodiesel much more susceptible to oxidation or autoxidation during long-term storage than conventional petrodiesel. Increasing resistance to oxidation therefore requires the use of antioxidants. This paper investigates the effectiveness of the N,N′-di-sec-butyl-p-phenylenediamine (1) as a antioxidant to improve the oxidative stability of soybean, sunflower and canola biodiesel. Results indicate that the induction period for oxidation of soybean and canola biodiesel is significantly improved with the addition of only 0.2 ppm of the 1, reaching the oxidative stability specification (6 h by the Rancimat test). For sunflower biodiesel, 2.0 ppm of the 1 was necessary. This additive is also shown to be efficiently detected by the easy ambient sonic-spray ionization mass spectrometry technique, indicating that 1 and its analogues and derivative...

In the present investigation, the application of NMR spectroscopic techniques was extensively used with an objective to explore the biodiesel potential of biomass cultivated on a lab scale using strains of Chlorella vulgaris and Scenedesmus ecornis. The effect of variation in the composition of culturing medium on the neutral and polar lipids productivity, and fatty acid profile of solvent extracts of microalgae biomass was studied. Determination of unsaturated fatty acid composition (C18:N = 1-3, ω3 C20:5, ω3 C22:6), polyunsaturated fatty esters (PUFEs), saturated fatty acids (SFAs), unsaturated fatty acids (UFAs), free fatty acids (FFAs), and iodine value were achieved from a single (1)H NMR spectral analysis. The results were validated by (13)C NMR and GC-MS analyses. It was demonstrated that newly developed methods based on (1)H and (13)C NMR techniques are direct, rapid, and convenient for monitoring the microalgae cultivation process for enhancement of lipid productivity and their quality aspects in the solvent extracts of microalgal biomasses without any sample treatment and prior separation compared to other methods. The fatty acid composition of algae extracts was found to be similar to vegetable and fish oils, mostly rich in C16:0, C18:N (N = 0 to 3), and n-3 omega polyunsaturated fatty acids (PUFAs). The lipid content, particularly neutral lipids, as well as most of the quality parameters were found to be medium specific by both the strains. The newly developed methods based on NMR and ultrasonic procedure developed for efficient extraction of neutral lipids are cost economic and can be an effective aid for rapid screening of algae strains for modulation of lipid productivity with desired biodiesel quality and value-added products including fatty acid profile.

Brazil is the largest producer of sugar cane bioethanol in the world. Isotope ratio mass spectrometry (IRMS) is the technique of choice to certify the origin/raw materials for ethanol production, but the lack of certified reference materials (CRMs) for accurate measurements of δ(13) C values traceable to Vienna Pee Dee Belemnite (VPDB), the international zero point for (13) C/(12) C measurements, certified and compatible with gas chromatography (GC)/IRMS instruments may compromise the accuracy of δ(13) C determinations.We evaluated the influence of methods for the calibration and normalization of raw δ(13) C values of ethanol samples. Samples were analyzed by GC/C/IRMS using two different GC columns. Different substances were used as isotopic standards for the working gas calibration. The δ(13) C values obtained with the three methods of normalization were statistically compared with those obtained with elemental analyzer (EA)/IRMS, since the δ(13) C results obtained using EA are traceable to VPDB via the NBS 22 reference material.It was observed that both the isotopic reference material for CO2 calibration and the GC column have a major effect on the δ(13) C measurements, leading to a bias of almost 2-3 ‰ in the δ(13) C values. All three methods of normalization were equivalent in performance, enabling an improvement in the GC/C/IRMS accuracy, compared with the EA/IRMS reference values for the samples.All the methods of CO2 calibration, chromatography and normalization presented in this work demonstrated several sources of traceability and accuracy loss for the determination of δ(13) C values in ethanol fuel samples by GC/C/IRMS. This work has also shown the importance of using proper CRMs traceable to VPBD that should be compatible and certified using GC/C/IRMS, ideally in a wide range of δ(13) C values. This is important not only for bioethanol fuel samples, but also for many analytes commonly analyzed by IRMS.

Presently the world is preoccupied with concerns of soaring oil prices, energy insecurity, and increasing challenges to minimize emissions of green house gases. All these issues certainly call for major reexamination of fossil energy based present technological paradigms and in favor of decisions on investments in clean energy, which supports sustainable development. Many official documents show that the world has already acknowledged this shifting scenario, as investments in renewable energy have been growing on a steady trajectory. According to data presented by the United Nations, green energy overtook fossil fuels in attracting investment for power generation for the first time in 2008. The trend has been confirmed by the last report of UNEP, Global Trends in Renewable Energy Investment 2011, which states that in 2010 there has been a 32% rise in green energy investments worldwide. In this context, the production of biofuels on a large scale has become a dominant focus for technical and political discussions all over the world, aimed at diversifying the energy mix of countries. Nations that are capable of innovating through sound investments and breakthrough achievements will enjoy tremendous advantages, both because these emerging technologies will support their industrial expansion as well as the likelihood that high value-added exports can be generated. The enthusiasm surrounding the biofuels sector has led many countries to introduce policies of offering subsidies to stimulate the production of bioethanol and biodiesel. To speed up their introduction in the energy portfolio, a growing number of governments have been requiring that biofuels be blended with fossil fuels. In USA, for instance, bioethanol blended with gasoline can contain as high as 85% bioethanol from corn (E85), or more usually other mixtures, such as E10 and E20. Similar to bioethanol, biodiesel mixtures are denominated ‘‘BXX,’’ X being the percentage of biodiesel, e.g., B2 means 2% of biodiesel, B5, 5%, up to B100. Brazil is the most traditional economy in the production of bioethanol from sugarcane, where the first governmental decree establishing a 5% blend of bioethanol with gasoline was issued in 1931. Since then, the composition has varied and nowadays is set up to around 20%, depending on the price of the fuels. Besides, in Brazil, it is possible to find vehicles that run solely on bioethanol. Moreover, the so-called flex-vehicles can run on any mixture of gasoline and bioethanol. The country has also been making sound investments for the production of biodiesel, aiming to reach a composition level of B8 in 2013. More recently, the strategy of many producing countries, including Brazil, has moved to the forefront of turning biofuels into a full-fledged world commodity. Measures taken by some countries to protect domestic markets have been continually distorting international market of commodities for decades. Most evident and traditional measures have been related to tariffs and quotas, but other more subtle measures have been taken as well, such as subsidies to domestic producers and too harsh technical requirements. H. S. Brandi (&) R. J. Daroda T. L. Souza National Institute of Metrology, Quality and Technology (Inmetro), Av. Nossa Senhora das Gracas 50, Xerem, Duque de Caxias, RJ 25250-020, Brazil e-mail: hsbrandi@inmetro.gov.br

Direct methods based on (1)H NMR spectroscopic techniques have been developed for the determination of neutral lipids (triglycerides and free fatty acids) and polar lipids (glyceroglycolipids/phospholipids) in the solvent extracts of oleaginous microalgal biomasses cultivated on a laboratory scale with two species in different media. The chemical shift assignments observed in the (1)H and (13)C NMR spectra corresponding to unsaturated (C18:N, N = 1-3, C20:3, C20:5, C22:6, epoxy) and saturated (C14-C18) fatty acid ester components in a complex matrix involving overlapped resonances have been unambiguously confirmed by the application of 2D NMR spectroscopy (total correlation spectroscopy and heteronuclear single quantum coherence-total correlation spectroscopy). The study of the effect of a polar lipid matrix on the determination of neutral lipids by an internal reference blending process by a systematic designed experimental protocol has provided absolute quantification. The fatty acid composition of algal extracts was found to be similar to that of vegetable oils containing saturated (C16-C18:0) and unsaturated (C18:N, N = 1-3, C20:N, N = 3-4, C22:6) fatty acids as confirmed by NMR spectroscopy and gas chromatography-mass spectrometry analyses. The NMR methods developed offer great potential for rapid screening of algal strains for generation of algal biomass with the desired lipid content, quality, and potential for biodiesel and value-added polyunsaturated fatty acids in view of the cost economics of the overall cost of generation of the biomass.

This paper proposes the use of easy ambient sonic-spray ionization mass spectrometry (EASI-MS) to detect markers of high-level oxidation in biodiesel via a simple and rapid single-shot analytical protocol. Soybean biodiesel was oxidized in Rancimat and then analyzed at different time periods by both EASI-MS and traditional physicochemical methods. Major changes in the EASI(+)-MS profile as well in the peroxide value, acidity, and kinematic viscosity were observed after the induction period (IP). Fatty acid methyl esters (FAME) and their respective hydroperoxides were primarily identified using EASI-MS in fresh biodiesel and at the initial stages of oxidation. After the IP, EASI-MS revealed the formation of dimers and low-mass non-volatile molecules, such as aldehydes, due to hydroperoxide breakdown. Both the dimers and aldehydes are attributed to secondary oxidation products. Therefore, EASI-MS was found to provide a fast, direct, and accurate technique to identify markers in biodiesel with high-level of oxidation. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim., The authors are grateful to the Agency of the São Paulo Research Foundation (FAPESP) for their financial support, and to the Coordination for the Improvement of Higher Level or Education Personnel (CAPES) and the National Council for Scientific and Technological Development (CNPq) for the scholarship.

We have studied the behavior of isomers and analogues by traveling wave ion mobility mass spectrometry (TWIM-MS) using drift-gases with varying masses and polarizabilities. Despite the reduced length of the cell (18 cm), a pair of constitutional isomers, N-butylaniline and para-butylaniline, with theoretical collision cross-section values in helium (ΩHe ) differing by as little as 1.2 Å(2) (1.5%) but possessing contrasting charge distribution, showed baseline peak-to-peak resolution (Rp-p ) for their protonated molecules, using carbon dioxide (CO2), nitrous oxide (N2O) and ethene (C2H4 ) as the TWIM drift-gas. Near baseline Rp-p was also obtained in CO2 for a group of protonated haloanilines (para-chloroaniline, para-bromoaniline and para-iodoaniline) which display contrasting masses and theoretical ΩHe , which differ by as much as 15.7 Å(2) (19.5%) but similar charge distributions. The deprotonated isomeric pair of trans-oleic acid and cis-oleic acid possessing nearly identical theoretical ΩHe and ΩN2 as well as similar charge distributions, remained unresolved. Interestingly, an inversion of drift-times were observed for the 1,3-dialkylimidazolium ions when comparing He, N2 and N2O. Using density functional theory as a means of examining the ions electronic structure, and He and N2-based trajectory method algorithm, we discuss the effect of the long-range charge induced dipole attractive and short-range Van der Waals forces involved in the TWIM separation in drift-gases of differing polarizabilities. We therefore propose that examining the electronic structure of the ions under investigation may potentially indicate whether the use of more polarizable drift-gases could improve separation and the overall success of TWIM-MS analysis.

New alternative energy has been an interesting field for research and development in attempt to diminish the environmental imbalance that has occasioned several climatic changes occurred over the past decades. This research area has obtained a great advance in methodologies to produce alternative energies, where is possible to produce energy through alternative sources that usually are less polluting and are useful to replace the crude oil and petroleum derivatives. These alternative energy sources have become an important tool in the fight against pollution. Among some alternatives energy, stands out biodiesel an available alternative fuel, which is capable to diminish problems related to important areas as environmental and social development. From this point INMETRO, has developing, in line with the policy of the Brazilian government, studies to obtain alternative and renewable sources of energy as bioethanol and biodiesel. This work shows a methyl biodiesel short-time stability study in attempt to observe how much temperature can affect the biodiesel quality. Were used two methodologies to verify the biodiesel quality, the oxidative stability by Rancimat method and Iodine Index.

Travelling wave ion mobility mass spectrometry (TWIM-MS) with post-TWIM and pre-TWIM collision-induced dissociation (CID) experiments were used to form, separate and characterize protomers sampled directly from solutions or generated in the gas phase via CID. When in solution equilibria, these species were transferred to the gas phase via electrospray ionization, and then separated by TWIM-MS. CID performed after TWIM separation (post-TWIM) allowed the characterization of both protomers via structurally diagnostic fragments. Protonated aniline (1) sampled from solution was found to be constituted of a ca. 5:1 mixture of two gaseous protomers, that is, the N-protonated (1a) and ring protonated (1b) molecules, respectively. When dissociated, 1a nearly exclusively loses NH(3) , whereas 1b displays a much diverse set of fragments. When formed via CID, varying populations of 1a and 1b were detected. Two co-existing protomers of two isomeric porphyrins were also separated and characterized via post-TWIM CID. A deprotonated porphyrin sampled from a basic methanolic solution was found to be constituted predominantly of the protomer arising from deprotonation at the carboxyl group, which dissociates promptly by CO(2) loss, but a CID-resistant protomer arising from deprotonation at a porphyrinic ring NH was also detected and characterized. The doubly deprotonated porphyrin was found to be constituted predominantly of a single protomer arising from deprotonation of two carboxyl groups.

The results of an interlaboratory comparison, using various measurement methods to carry out biodiesel testing, are presented and the findings are discussed. The interlaboratory comparison was organised within the framework of an EU-funded project called BIOREMA. A general overview of the project and results of an interlaboratory comparison on bioethanol are published as Part 1 and 2 of this series of papers. In the study presented here, reference values, provided by national metrology institutes and expert laboratories, were used for evaluating the results. Consensus values, derived from the results of all participants, were used to assess any bias between the results from the national metrology institutes and testing laboratories. The emphasis in this interlaboratory comparison was not the performance rating of the individual laboratories, but recognising and interpreting differences caused by the measurement methods applied. For most biodiesel parameters, a good agreement of measurement results was found among different methods, and between the consensus and reference values. The study material was a rapeseed oil fatty acid methyl ester, for which it was demonstrated that it is feasible to prepare and characterise reference materials for biodiesel with well-established reference values for many parameters., JRC.D.2-Standards for Innovation and sustainable Development

The use of CO(2) as a massive and polarizable drift gas is shown to greatly improve peak-to-peak resolution (R(p-p) ), as compared with N(2) , for the separation of disaccharides in a Synapt G2 traveling wave ion mobility cell. Near or baseline R(p-p) was achieved for three pairs of sodiated molecules of disaccharide isomers, that is, cellobiose and sucrose (R(p-p) = 0.76), maltose and sucrose (R(p-p) = 1.04), and maltose and lactose (R(p-p) = 0.74). Ion mobility mass spectrometry using CO(2) as the drift gas offers therefore an attractive alternative for fast and efficient separation of isomeric disaccharides.

Venturi easy ambient sonic spray ionization mass spectrometry in both its liquid (V(L) -EASI-MS) and solid sample modes (V(S) -EASI-MS) is shown to provide nearly immediate and secure typification of woods, as demonstrated for Mahogany, an endangered and most valuable type of tropical wood. This reddish wood displays unique phytochemical markers (phragmalin-type limonoids) which are rapidly detected from the wood surface by V(S) -EASI-MS or from a simple methanol extract of a tiny wood chip by V(L) -EASI-MS. Unique profiles were obtained for Mahogany (Swietenia macrophylla) whereas genuine samples of six other similar types of woods, which are commonly falsified by artificial coloring and commercialized as Mahogany, display also typical but dissimilar pythochemical profiles as compared to that of the authentic wood. Variable and atypical chemical profiles were observed for artificially colored woods. Secure chemical characterization via V(S) -EASI-MS or V(s) -EASI-MS fingerprints of Mahogany and other types of woods with similar appearance should help to control the illegal logging and trade of this and other endangered woods and their falsification, and to create certified standards.

The ability of travelling wave ion mobility mass spectrometry (TWIM-MS) to resolve cationic meta/para and cis/trans isomers of mono-, di-, tri- and tetra-ruthenated supramolecular porphyrins was investigated. All meta isomers were found to be more compact than the para isomers and therefore mixtures of all isomeric pairs could be properly resolved with baseline or close to baseline peak-to-peak resolution (R(p-p)). Di-substituted cis/trans isomers were found, however, to present very similar drift times and could not be resolved. N(2) and CO(2) were tested as the drift gas, and similar α but considerably better values of R(p) and R(p-p) were always observed for CO(2).

Corrole and four of its isomers with subtle structural changes promoted by exchange of nitrogen and carbon atoms in the corrole ring have been studied by traveling wave ion mobility mass spectrometry and collision induced dissociation experiments. Significant differences in shapes and charge distributions for their protonated molecules were found to lead to contrasting gas phase mobilities, most particularly for corrorin, the most "confused" isomer. Accordingly, corrorin was predicted by B3LYP/6-31g(d,p) and collisional cross section calculations to display the most compact tri-dimensional structure, whereas NCC4 and corrole were found to be the most planar isomers. Better resolution between the corrole isomers was achieved using the more polarizable and massive CO(2) as the drift gas. Sequential losses of HF molecules were found to dominate the dissociation chemistry of the protonated molecules of these corrole isomers, but their unique structures caused contrasting labilities towards CID, whereas NCC4 showed a peculiar and structurally diagnostic loss of NH(3), allowing its prompt differentiation from the other isomers.

Travelling-wave ion mobility mass spectrometry was used to measure the intrinsic mobility of a series of gaseous supra-cation and supra-anion aggregates of several ionic liquids. Close mobilities were observed in a T-wave cell filled with helium at ca. 0.8 mbar for [(DAI) n+1 (X) n ] + (DAI is the 1,3-dialkylimidazolium cation and X is the anion) as compared to the respective anions [(DAI) n (X) n+1 ] - for n=0 to 9. The anomalous behavior reported before in the condensed phase seems therefore to be related to the unique structural organization of pure ionic liquids that provides both polar and non-polar regions with directionality in which the anionic species are more retained than the cationic species in the salt network.

Meta-chlorophenylpiperazine (m-CPP) is a new illicit drug that has been sold as ecstasy tablets. Easy ambient sonic-spray ionization mass spectrometry (EASI-MS) and X-ray fluorescence spectrometry (XRF) are shown to provide relatively simple and selective screening tools to distinguish m-CPP tablets from tablets containing amphetamines (mainly 3,4-methylenedioxymethamphetamine (MDMA)). EASI-MS detects the active ingredients in their protonated forms: [m-CPP + H](+) of m/z 197, [MDMA + H](+) of m/z 194, and [2MDMA + HCl + H](+) of m/z 423 and other ions from excipients directly on the tablet surface, providing distinct chemical fingerprints. XRF identifies Cl, K, Ca, Fe, and Cu as inorganic ingredients present in the m-CPP tablets. In contrast, higher Cl concentrations and a more diverse set of elements (P, Cl, Ca, Fe, Cu, Zn, Pt, V, Hf, Ti, Pt, and Zr) were found in MDMA tablets. Principal component analysis applied to XRF data arranged samples in three groups: m-CPP tablets (four samples), MDMA tablets (twenty three samples), and tablets with no active ingredients (three samples). The EASI-MS and XRF techniques were also evaluated to quantify m-CPP in ecstasy tablets, with concentrations ranging from 4 to 40 mg of m-CPP per tablets. The m-CPP could only be differentiated from its isomers (o-CPP and for the three isomers p-CPP) by traveling wave ion mobility mass spectrometry and NMR measurements.

The oil from the seeds of the “Andiroba” tree, which is found throughout most tropical America, contains high levels of unsaturated triacylglycerols (TAG), which makes it attractive to the cosmetics industry. A significant amount of limonoids also confers to this Amazonian oil several pharmaceutical and medical properties. In addition, the oil is also a potential feedstock for biodiesel production, and its many uses have intensified its extractive exploitation in recent years. Herein we report on the characterization of the TAG, free fatty acids (FFA) and limonoid profiles of the Andiroba oil via mass spectrometry (MS) fingerprinting using direct electrospray ionization mass spectrometry (ESI-MS). An ambient desorption/ionization technique known as easy ambient sonic-spray ionization (EASI-MS) was also evaluated with similar results. ESI-MS was performed either for a methanolic solution of a few microliters of the fresh oil or from a simple aqueous extract whereas EASI-MS was applied directly to a droplet of the oil resting on a paper surface. The efficacy of these MS fingerprinting techniques requiring no pre-separation and no or very simple sample preparation protocols was investigated and compared for the typification and quality of this valuable Amazonian oil.

In recent years, biodiesel has gained considerable attention because of the increasing concern for the environmental problems associated with the use of fossil fuels. The determination of fuel quality is an issue of great importance to the successful commercialization of biodiesel. According to ASTM and EN standards, the analysis of free and total glycerin, contaminants that can lead to serious engine problems, must be carried out by GC analysis. This work presents an alternative method for identifying and quantifying these major contaminants in biodiesel. EASI(+)-MS has shown to function as a fast and secure method, with little or no sample preparation and no pre-separation.

High performance thin layer chromatography (HPTLC) combined with on-spot detection and characterization via easy ambient sonic-spray ionization mass spectrometry (EASI-MS) is applied to the analysis of biodiesel (B100) and biodiesel-petrodiesel blends (BX). HPTLC provides chromatographic resolution of major components whereas EASI-MS allows on-spot characterization performed directly on the HPTLC surface at ambient conditions. Constituents (M) are detected by EASI-MS in a one component-one ion fashion as either [M + Na](+) or [M + H](+). For both B100 and BX samples, typical profiles of fatty acid methyl esters (FAME) detected as [FAME + Na](+) ions allow biodiesel typification. The spectrum of the petrodiesel spot displays a homologous series of protonated alkyl pyridines which are characteristic for petrofuels (natural markers). The spectrum for residual or admixture oil spots is characterized by sodiated triglycerides [TAG + Na](+). The application of HPTLC to analyze B100 and BX samples and its combination with EASI-MS for on-spot characterization and quality control is demonstrated.

Carbon monoxide and hydrogen at pressures below 300 atm and temperatures below 200 °C in chelating ethers (glymes) or 2-methoxyethanol containing cobalt and other metal carbonyls react to give ethanol and other oxygenated products; on the basis of reduction using D2 and study of cobalt complexes, reaction mechanisms are proposed.

The reaction of Ti(η-C5H5)2Cl2 with Li[Mn(η-C5H4)(CO)3] in a mixture of tetrahydrofuran and diethyl ether (5 : 1) at –78 °C gives the compound Ti(η-C5H5)2[σ-(η-C5H4)Mn(CO)3]2, the structure of which has been determined by single-crystal X-ray diffraction methods. Crystals are monoclinic, space group C2/c, a= 13.474, b= 8.085, c= 22.327 A, β= 105.08°, and Z= 4. The structure, solved by the heavy-atom method and refined by least squares {R= 0.032 for 2 140 observed [Fo > 3σ(Fo)] data}, comprises molecules with C2 symmetry in which the Ti atom is σ bonded to the cyclopentadienyl rings of two Mn(η-C5H4)(CO)3 groups. Bond lengths and angles are as expected but with significant distortions in the manganese C5H4 rings.

Reduction of CO by H2 using carbonyls of Fe, Ru, and Os in 2-methoxyethanol below 200 °C and 200 atm gives dimethyl ether and diethyl ether (Fe), methanol and acetone (Ru), and methanol, methyl formate, acetone, and hydroxyethyl formate (Os); catalytic cycles are proposed.

Win this paper we report the stoichiometric reduction of carbon monoxide coordinated to a metal, by hydrogen (hydride) using a homogeneus ionic system formed by combining two ionic complexes suche as [MoH 3 (PMePh 2 ) 3 ] + or [WH 5 (PMePh 2 ) 4 ] + with [Rh 12 (CO) 34 ] 2- or [Co (CO) 4 ] - in polar medium acting as solvent. In a atmosphere os synthesis-gas, using pressures from 5 to 100 atms. and temperatures from 25 to 200°C a detectable amount of ethylene glycol were produced and identified by gas-liquidi-chromatography (g.l.c.), infrared, 1 H n.m.r. and gas chromatography - mass spectra (G.C./M.S.).