Infusion Electrospray Ionization Mass Spectrometry Research Articles

Photoelectrocatalytic Oxidation of Ethinylestradiol on a Ti/TiO<sub>2</sub> Electrode: Degradation Efficiency and Search for By-Products

The degradation of ethinylestradiol (EE, an orally bio-active estrogen) in an aqueous-methanolic solution using a Ti/TiO2 thin-film electrode and UV radiation (a photoelectrocatalytic system) was evaluated. Hence, HPLC/UV analysis shows that EE (at 0.34 mmol) is totally consumed after 30 minutes of exposure to the photoelectrocatalytic system in the presence of Na2SO4 (0.1 mol·L-1) and with an applied bias potential of +1.0 V versus the Ag/AgCl reference electrode. Moreover, monitoring by direct infusion electrospray ionization mass spectrometry (ESI-MS) and SPME-GC/ MS (solid phase microextraction coupled with gas chromatography-mass spectrometry) reveals that apparently no degradation products are formed under these conditions. Hence, this study demonstrates that the photoelectrocatalytic system can be efficiently used to promote the complete degradation (and likely mineralization) of this hormone under these conditions.

A framework for selecting analytical techniques in profiling authentic and counterfeit Viagra and Cialis

Several analytical techniques aimed at profiling drugs are deemed costly and time consuming, and may not be promptly available for analysis when required. This paper proposes a method for identifying the analytical techniques providing the most relevant data for classification of drug samples into authentic and unauthentic categories. For that matter, we integrate principal components analysis (PCA) to k-Nearest Neighbor (KNN) and Support Vector Machine (SVM) classification tools. PCA is first applied to data from five techniques, i.e., physical profile, X-ray fluorescence (XRF), direct infusion electrospray ionization mass spectrometry (ESI-MS), active pharmacological ingredients profile (ultra performance liquid chromatography, UPLC–MS), and infrared spectroscopic profile (ATR-FTIR). Subsets of PCA scores are then combined with a “leave one subset out at a time” approach, and the classification accuracy using KNN and SVM evaluated after each subset is omitted. Subsets yielding the maximum accuracy indicate the techniques to be prioritized in profiling applications. When applied to data from Viagra and Cialis, the proposed method recommended using the data from UPLC–MS, physical profile and ATR-FTIR techniques, which increased the categorization accuracy. In addition, the SVM classification tool is suggested as more accurate when compared to the KNN.

Antioxidant activity of grape products and characterization of components by electrospray ionization mass spectrometry

Grapes are known for their health benefits and high antioxidant activity due to phenolic content. Our work provides metabolic fingerprints of three grape products, namely grape juice (GJ), grape juice concentrate (GJC) and grape skin extract powder (GSE). Using direct infusion electrospray ionization mass spectrometry (ESI–MS) and evaluating the relationship between total lphenolic content and antioxidant activity, it is possible to compare which product has the best effectiveness. Fingerprints of GJC and GSE showed similar characteristic distributions of resveratrol and pterostilbene in relatively significant abundances. GJC provided higher antioxidant activity/phenolic ratio; therefore, the identified phenolic compounds from GJC may offer enhanced antioxidant potential when compared to the other two samples (GJ and GSE).

Electrospray ionization mass spectrometry and partial least squares discriminant analysis applied to the quality control of olive oil

Direct infusion electrospray ionization mass spectrometry in the positive ion mode [ESI(+)-MS] is used to obtain fingerprints of aqueous-methanolic extracts of two types of olive oils, extra virgin (EV) and ordinary (OR), as well as of samples of EV olive oil adulterated by the addition of OR olive oil and other edible oils: corn (CO), sunflower (SF), soybean (SO) and canola (CA). The MS data is treated by the partial least squares discriminant analysis (PLS-DA) protocol aiming at discriminating the above-mentioned classes formed by the genuine olive oils, EV (1) and OR (2), as well as the EV adulterated samples, i.e. EV/SO (3), EV/CO (4), EV/SF (5), EV/CA (6) and EV/OR (7). The PLS-DA model employed is built with 190 and 70 samples for the training and test sets, respectively. For all classes (1-7), EV and OR olive oils as well as the adulterated samples (in a proportion varying from 0.5 to 20.0% w/w) are properly classified. The developed methodology required no ions identification and demonstrated to be fast, as each measurement lasted about 3 min including the extraction step and MS analysis, and reliable, because high sensitivities (rate of true positives) and specificities (rate of true negatives) were achieved. Finally, it can be envisaged that this approach has potential to be applied in quality control of EV olive oils.

Phytochemical markers of different types of red propolis

Propolis is a resin that bees collect from different plant sources and use in the defense of the bee community. The intricate composition of propolis varies depending on plant sources from different geographic regions and many types have been reported. Red coloured propolis found in several states in Brazil and in other countries has known antimicrobial and antioxidant activity. Different analytical methods have been applied to studies regarding the chemical composition and plant origins of red propolis. In this study samples of red propolis from different regions have been characterised using direct infusion electrospray ionisation mass spectrometry (ESI(-)-MS) fingerprinting. Data from the fingerprints was extracted and analysed by multivariate analysis to group the samples according to their composition and marker compounds. Despite similar colour, the red coloured propolis samples were divided into three groups due to contrasting chemical composition, confirming the need to properly characterise the chemical composition of propolis.

Lanostane triterpenoids from the fungus Ceriporia lacerate associated with Acanthaster planci

Under chemical prescreening by direct infusion electrospray ionization mass spectrometry, three new lanostane triterpenoids, 3β-acetoxy-15α-hydroxylanosta-8,24-dien-21-oic acid (1), 1β,3β-dihydroxylanosta-8,24-dien-21-oic acid (2), and 15α-hydroxy-3-oxolanosta-8,24-dien-21-oic acid (3), together with two known lanostane triterpenoids, 3β,15α-dihydroxylanosta-8,24-dien-21-oic acid (4) and 3β-hydroxylanosta-8,24-dien-21-oic acid (5), were isolated from the marine fungus Ceriporia lacerate derived from Acanthaster planci. Their structures were established by MS and 1D and 2D NMR spectroscopic techniques.

Quantitative Profiling of Major Neutral Lipid Classes in Human Meibum by Direct Infusion Electrospray Ionization Mass Spectrometry

The purpose of this investigation was to better understand lipid composition in human meibum. Intact lipids in meibum samples were detected by direct infusion electrospray ionization mass spectrometry (ESI-MS) analysis in positive detection mode using sodium iodide (NaI) as an additive. The peak intensities of all major types of lipid species, that is, wax esters (WEs), cholesteryl esters (CEs), and diesters (DEs) were corrected for peak overlapping and isotopic distribution; an additional ionization efficiency correction was performed for WEs and CEs, which was simplified by the observation that the corresponding ionization efficiency was primarily dependent on the specific lipid class and saturation degree of the lipids while independent of the carbon chain length. A set of WE and CE standards was spiked in meibum samples for ionization efficiency determination and absolute quantitation. The absolute amount (μmol/mg) for each of 51 WEs and 31 CEs in meibum samples was determined. The summed masses for 51 WEs and 31 CEs accounted for 48 ± 4% and 40 ± 2%, respectively, of the total meibum lipids. The mass percentages of saturated and unsaturated species were determined to be 75 ± 2% and 25 ± 1% for CEs and 14 ± 1% and 86 ± 1% for WEs. The profiles for two types of DEs were also obtained, which include 42 α,ω Type II DEs, and 21 ω Type I-St DEs. Major neutral lipid classes in meibum samples were quantitatively profiled by ESI-MS analysis with NaI additive.

Artificially-aged cachaça samples characterised by direct infusion electrospray ionisation mass spectrometry

Direct infusion electrospray ionisation mass spectrometry in the negative ion mode [ESI(−)-MS] was employed to evaluate the authenticity of aged cachaças, a traditional and valuable Brazilian alcoholic beverage prepared from the distillation of brewed sugarcane juice and aged in barrels made of common woods. Counterfeit samples were prepared by adding dyes, sawdust or essences to a freshly-distiled, much less valuable sample (white cachaça) to simulate the 1–2years long natural ageing in wooden barrels. A simple visual inspection revealed remarkable differences between the ESI(−)-MS of the authentic samples (aged in oak or amburana casks) and the artificially-aged counterfeit samples. A set of diagnostic ions were detectable in the ESI(−)-MS of the authentic samples aged in oak (m/z 197, 241, 301 and 307) and amburana (m/z 271 and 377/379). This fast and direct methodology seems useful as a routine procedure to monitor this highly profitable and common counterfeit practice.

Electrospray Ionization Mass Spectrometry (ESI-MS) monitoring of the photolysis of diazinon in aqueous solution: Degradation route and toxicity of by-products against Artemia salina

The photolytic degradation of diazinon, an organophosphorus pesticide, in aqueous medium under assorted pH values was continuously monitored by direct infusion electrospray ionization mass spectrometry (ESI-MS). The results indicated that the UV radiation was quite efficient in promoting the pesticide degradation at the three pH levels evaluated (5, 7 and 8). The m/z of the most abundant ions observed in the mass spectra (MS), in conjunction with the fragmentation patterns of such ionic species (MS/MS data), made possible the proposition of chemical structures for the main by-products formed. As a result, routes for the photodegradation of diazinon in aqueous solution could thus be suggested. In the assays using Artemia salina (brine shrimp) it was verified that the photodegradation products exhibited much lower toxicity than the primary substrate. Aiming at mimicking the conditions ordinarily found in water treatment plants, an additional series of tests was conducted with a solution containing sodium hypochlorite and diazinon. This solution, when not exposed to UV radiation, exhibited high toxicity against the microorganisms. Under the influence of UV radiation, however, the toxicity rates decreased dramatically. This result is relevant because it points toward the confident application of UV radiation to neutralize the deleterious effects caused by diazinon (and perhaps other organophosphorus pesticides) as well as sodium hypochlorite to the environment.

Data-driven strategy for the discovery of potential urinary biomarkers of habitual dietary exposure

An understanding of causal relations between diet and health is hindered by the lack of robust biological markers of food exposure. We aimed to develop a data-driven procedure to discover urine biomarkers indicative of habitual exposure to different foods. The habitual diet of 68 participants was assessed by using 4 food-frequency questionnaires over 3 mo, and participants were assigned to different consumption-frequency classes for 58 dietary components. Flow infusion electrospray-ionization mass spectrometry followed by supervised multivariate data analysis was used to determine whether the chemical composition of urine was related to specific differences in the consumption levels of each food. Foods were eaten habitually in 1 of 5 basic patterns differing in range and distribution of consumption frequency. Overnight, 24-h, and fasting urine samples proved useful for biomarker lead discovery with habitual citrus exposure used as a paradigm. Exposure level discrimination robustness improved linearly as urine samples from low-frequency citrus consumers were compared with urine samples from participants reporting increasingly higher intakes. For all foods, distinctiveness and consumption-frequency range influenced the likelihood that differential dietary exposure could be detected. Model output statistics indicated foods for which biomarker lead discovery was feasible. Metabolites proposed previously as acute intake biomarkers of citrus (proline betaine), oily fish (methylhistidine), coffee (dihydrocaffeic acid derivatives), and tomato (phenolic metabolites) were also biomarkers of habitual exposure. A significance threshold in modeling output statistics was determined to guide the discovery of potential biomarkers for other foods. This data-driven strategy can identify urinary metabolites associated with habitual exposure to specific foods. This trial has the UK registration number 4349 and was registered at isrtcn.org as CCT-NAPN-A13175.

Human serum albumin cysteinylation is increased in end stage renal disease patients and reduced by hemodialysis: mass spectrometry studies

The aim of the present work was to monitor the covalent modifications of human serum albumin (HSA) in end stage renal diseases (ESRD) non-diabetic patients, before and after hemodialysis (HD), by direct infusion electrospray mass spectrometry (ESI-MS). Human serum samples were collected from healthy subjects (n = 10, 20–60 yr) and age-matched ESRD patients (n = 8) before and after HD, purified by affinity chromatography and analyzed by a triple-quadrupole mass spectrometer. The deconvoluted spectra from healthy subjects were all characterized by three peaks attributed to non-glycated mercaptoalbumin (HSA-SH) and to the corresponding adducts with cysteine (HSA-Cys) and glucose (HSA-Glc); relative contents: mercaptoalbumin in both glycated and non-glycated form, HSA-SHt (74 ± 6%), HSA-Cys (26 ± 5%) and HSA-Glc (24 ± 3%). HSA isolated from ESRD patients before HD was characterized by a significant reduction of HSA-SHt (42 ± 7%), and by a concomitant increase of the HSA-Cys adduct (58 ± 7%). Hemodialysis significantly reduced the cysteinylated form (37 ± 7%) and restored HSA-SHt (63 ± 8%) in all the ESRD patients. The mechanism of thiol oxidation and cysteinylation was then studied by mass spectrometry, using LQQCPF as a model peptide and H2O2 as an oxidizing agent.

Simultaneous determination of neutral, basic and acidic pesticides in aquatic environmental matrices by solid-phase extraction and liquid chromatography electrospray ionization mass spectrometry

Simultaneous determination of a wide variety of pesticides and herbicides in environmental waters by liquid chromatography electrospray-ionization mass spectrometry (LC-ESI-MS) has been a challenging task due to matrix interferences. In this study, deuterated analogues and graphitized carbon black (GCB) solid-phase extraction (SPE) were investigated to compensate for and eliminate sample matrix interferences. Significant ion suppression and enhancement were observed when deuterated pesticides were used as internal standards. GCB cartridges can well retain neutral, basic and acidic pesticides and herbicides but the complete elution requires a combination of different characteristics of the solvent. A new procedure for SPE extraction and sample preparation was developed for simultaneous determination of neutral, basic pesticides and phenoxy acid herbicides in environmental waters by LC-ESI-MS. The proposed method was validated by examining the limit of detection and range of linearity and testing river water samples. The limit of detection ranged between 0.005 and 2 μg L−1 and the correlation coefficient for 5–5000 μg L−1 calibration standards was greater than 0.995. The recoveries of 79–121% from river water samples and relative standard deviations of 2–21% were obtained at the concentrations of 0.4–500 μg L−1 for 37 pesticides and herbicides.

Pterodon pubescens Oil: Characterisation, Certification of Origin and Quality Control via Mass Spectrometry Fingerprinting Analysis

The oil obtained from Pterodon pubescens (Leguminosae) seeds are known to display anti-cancer, anti-dermatogenic and anti-nociceptive activitiy. Phytochemical studies have demonstrated that its main constituents are diterpenoids with voucapan skeletons. Considering the potential biological activities of the oil, rapid and efficient methods for assessing its quality would facilitate certification and quality control. To develop a direct mass spectrometric fingerprinting method for the P. pubescens seed oil that would focus on the major diterpenoids constituents, enabling quality control, origin certification and recognition of marker species in commercially available products. Two techniques were used: (i) direct infusion electrospray ionisation (ESI) mass spectrometry after solvent extraction and dilution and (ii) ambient desorption/ionisation via easy ambient sonic-spray ionisation, EASI(+)-MS, performed directly on the seed surface or at a paper surface imprinted with the oil. From a combination of ESI-MS, HRESI-MS and ESI-MS/MS data, 12 diterpenes were characterised, and typical profiles were obtained for the oil extract or the crude oil via both ESI-MS and EASI-MS. These techniques require no or very simple sample preparation protocols and the whole analytical processes with spectra acquisition take just a few minutes. Both techniques, but particularly EASI-MS, provide simple, fast and efficient MS fingerprinting methodologies to characterise the P. pubescens oil with typical (di)terpene profiles being applicable to quality control and certification of authenticity and origin.

Attachment of Chloride Anion to Sugars: Mechanistic Investigation and Discovery of a New Dopant for Efficient Sugar Ionization/Detection in Mass Spectrometers

A new method for efficient ionization of sugars in the negative-ion mode of electrospray mass spectrometry is presented. Instead of using strongly hydrophobic dopants such as dichloromethane or chloroform, efficient ionization of sugars has been achieved by using aqueous HCl solution for the first time. This methodology makes it possible to use hydrophilic dopants, which are more appropriate for chromatographic separation techniques with efficient sugar ionization and detection in mass spectrometry. The interaction between chloride anions and monosaccharides (glucose and galactose) was studied by DFT in the gas phase and by implementing the polarizable continuum model (PCM) for calculations in solution at the high B3LYP/6-31+G(d,p)//B3LYP/6-311+G(2d,p) level of theory. In all optimized geometries of identified [M+Cl](-) anions, a non-covalent interaction exists. Differences were revealed between monodentate and bidentate complex anions, with the latter having noticeably higher binding energies. The calculated affinity of glucose and galactose toward the chloride anion in the gas phase and their chloride anion binding energies in solution are in excellent agreement with glucose and galactose [M+Cl](-) experimental intensity profiles that are represented as a function of the chloride ion concentration. Density functional calculations of gas-phase affinities toward chloride anion were also performed for the studied disaccharides sucrose and gentiobiose. All calculations are in excellent agreement with the experimental data. An example is introduced wherein HCl was used to effectively ionize sugars and form chlorinated adduct anions to detect sugars and glycosylated metabolites (anthocyanins) in real biological systems (Vitis vinifera grape extracts and wines), whereas they would not have been easily detectable under standard infusion electrospray mass spectrometry conditions as deprotonated species.

Oxidative degradation of bis(2,4,4‐trimethylpentyl)dithiophosphinic acid in nitric acid studied by electrospray ionization mass spectrometry

The selective separation of the minor actinides (Am, Cm) from the lanthanides is a topic of ongoing nuclear fuel cycle research, and dithiophosphinic acids are candidate ligands in these processes. Ligand instability has been noted under radiolytic and harsh acid conditions but explicit degradation pathways for ligands such as bis(2,4,4-trimethylpentyl)-dithiophosphinic acid (CyxH), the major compound in the commercial product Cyanex 301, have been elusive. Organic solutions of CyxH were contacted with aqueous solutions of HNO(3), and their degradation was studied by analyzing samples from these experiments by direct infusion electrospray ionization mass spectrometry. Ions were identified using accurate mass measurement and collision-induced dissociation. The positive ion spectra contained cationized CyxH cluster ions, and oxidatively coupled species (designated Cyx(2)) cationized by either H or Na. The Cyx(2)-derived ions increased with acid contact time. The negative ion spectra consisted almost entirely of the CyxH conjugate base. The negative ion spectra of the HNO(3)-contacted samples also contained conjugate bases corresponding to the dioxo and perthio derivatives of CyxH. CyxH is oxidized by acid contact to form the coupled species Cyx(2), and the dioxo species arise from subsequent oxidation of Cyx(2). Oxidative coupling increases with contact time, and with higher HNO(3) concentrations. The direct infusion measurements provided a simple approach for assessing degradation pathways and kinetics.

Flow infusion electrospray ionisation mass spectrometry for high throughput, non-targeted metabolite fingerprinting: a review

Producing a comprehensive overview of the chemical content of biologically-derived material is a major challenge. Apart from ensuring adequate metabolome coverage and issues of instrument dynamic range, mass resolution and sensitivity, there are major technical difficulties associated with data pre-processing and signal identification when attempting large scale, high-throughput experimentation. To address these factors direct infusion or flow infusion electrospray mass spectrometry has been finding utility as a high throughput metabolite fingerprinting tool. With little sample pre-treatment, no chromatography and instrument cycle times of less than 5 min it is feasible to analyse more than 1,000 samples per week. Data pre-processing is limited to aligning extracted mass spectra and mass-intensity matrices are generally ready in a working day for a month’s worth of data mining and hypothesis generation. ESI-MS fingerprinting has remained rather qualitative by nature and as such ion suppression does not generally compromise data information content as originally suggested when the methodology was first introduced. This review will describe how the quality of data has improved through use of nano-flow infusion and mass-windowing approaches, particularly when using high resolution instruments. The increasingly wider availability of robust high accurate mass instruments actually promotes ESI-MS from a merely fingerprinting tool to the ranks of metabolite profiling and combined with MS/MS capabilities of hybrid instruments improved structural information is available concurrently. We summarise current applications in a wide range of fields where ESI-MS fingerprinting has proved to be an excellent tool for “first pass” metabolome analysis of complex biological samples. The final part of the review describes a typical workflow with reference to recently published data to emphasise key aspects of overall experimental design.

Characterization of CMPO and its radiolysis products by direct infusion ESI-MS

Direct infusion electrospray ionization mass spectrometry (ESI-MS) approaches were developed for rapid identification of impurity compounds formed from octylphenyl-(N,N-(diisobutyl)carbamoylmethyl) phosphine oxide (CMPO) during alpha and gamma irradiation experiments of this compound in dodecane. CMPO is an aggressive Lewis base, and produces extremely abundant metal complex ions in the ESI-MS analysis that make identification of low abundance compounds that are less nucleophilic challenging. Radiolysis products were identified using several approaches including restricting ion trapping so as to exclude the abundant natiated CMPO ions, extraction of acidic products using aqueous NaOH, and extraction of basic products using HNO3. These approaches generated protonated, natiated and deprotonated species derived from CMPO degradation products formed via radiolytic cleavages of several different bonds. Cleavages of the amide and methylene–phosphoryl bonds appear to be favored by both alpha and gamma irradiation, while alpha irradiation also appears to induce cleavage of the methylene–carbonyl bond. The degradation products observed are formed from recombination of the initially formed radicals with hydrogen, methyl, isopropyl and hydroxyl radicals that are derived either from CMPO, contacted aqueous nitric acid, or the dodecane solvent.

Distillation of fermented sugarcane juice: fractions characterized by electrospray ionization mass spectrometry and multivariate data treatment

Direct infusion electrospray ionization mass spectrometry in the negative ion mode (ESI(-)-MS) was employed to discriminate among fractions arising from the distillation of fermented sugarcane juice during the production of cachaça, a typical Brazilian alcoholic beverage. Aliquots were collected in the course of distillation and their ESI(-)-MS shown to be almost indistinguishable by a simple visual inspection. However, when the ESI(-)-MS data were treated by the principal component analysis (PCA) and hierarchical clustering analysis (HCA) statistical methods, four major groups were clearly determined, the so-called head (two distinct clusters), heart and tail fractions. Furthermore, the recognition of diagnostic ions (and their respective intensities) enabled a more confident establishment of the cutoff position (i.e. the initial and final points of each fraction). In conclusion, ESI-MS, in conjunction with PCA or HCA approaches, proved to be a quite efficient method that allowed for a prompt characterization of each fraction derived from the distillation of brewed sugarcane. The results described herein can, therefore, be useful not only to optimize the production of cachaça but also to improve the quality of the final product.

Iberian ham typification by direct infusion electrospray and photospray ionization mass spectrometry fingerprinting

Iberian ham is a product of high commercial value whose quality mainly depends on breeding and feeding of pigs in an authorized way. Simple, fast, simple, reliable and high-throughput analytical methods are necessary to assure the quality of ham and for fraud prevention. Tandem mass spectrometry (MS/MS) is proposed as an advantageous alternative over other analytical techniques commonly used in this industry for product authentication. The analytical approach is based on direct infusion electrospray mass spectrometry (ESI(+)-MS) of dichloromethane/methanol (60:40) extracts of ham intramuscular fat. Similarly, atmospheric pressure photoionization ionization mass spectrometry (APPI(+)-MS) was used with a flow injection analysis system for sample introduction with methanol/water (50%) as the mobile phase and toluene as the dopant. All experiments were performed on an API QSTAR® XL Hybrid system using both ESI and APPI sources. The ESI(+)-MS mass spectra present several clusters of peaks attributed to ammonium adducts [M + NH(4) (+) ] of lipid compounds (mono-, di- and triacylglycerols - MGs, DGs, TGs, and free fatty acids - FFAs), that can be identified by MS/MS spectra. On the other hand, the APPI(+)-MS spectra present [M + H(+) ] ions and reflect a higher fragmentation of the sample. Five different types of Iberian ham samples were successfully classified using partial least-squares discriminant analysis (PLS-DA) of data from these samples. The application of direct infusion tandem mass spectrometry to dichloromethane/methanol extracts from intramuscular fat ham allows the simple, fast and reliable fingerprinting typification of different Iberian ham samples from pigs with different diets. With the proposed method, sample handling is minimal and chromatographic separation is not necessary, which represents an evident advantage over other analytical procedures usually used for this purpose.

The Famous Amazonian Rosewood Essential Oil: Characterization and Adulteration Monitoring by Electrospray Ionization Mass Spectrometry Fingerprinting

Direct infusion of samples via electrospray ionization mass spectrometry (ESI-MS) is shown to characterize unequivocally genuine samples of Amazonian Aniba rosaeodora Ducke (Rosewood) essential oils obtained either from the wood or leafs. The ESI-MS also distinguishes the essential oils from synthetic linalool; hence, adulteration by the synthetic oil is also clearly detected. The analysis requires no pretreatment or preseparation, and the most polar components of the essential oil are extracted with an acidified 1:1 methanol/water solution. This simple extract is then analyzed by direct infusion ESI-MS in the positive ion mode, which provides characteristic fingerprintings of the sample composition. The ESI-MS fingerprinting can be used therefore as a simple and fast (few minutes) method for authenticity and quality control of this famous Amazonian essential oil.