Direct Infusion Electrospray Ionization Research Articles

Discarded Carbon-Zinc Batteries as Source of an Efficient Heterogeneous Fenton-Like Catalyst Employed to Degrade Organic Molecules in an Aqueous Medium

The present work evaluates the feasibility of using the raw material collected from discarded zinc-carbon batteries as heterogeneous catalyst to degrade the dye Indigo Carmine in an aqueous solution. Besides the evident environmental application, this work also presents an economic alternative for the production of new catalysts used to remediate polluted waters. For this, discarded carbon-zinc batteries were gathered, disassembled and their anodic paste collected. After acidic treatment and calcination at 500°C, characterization measurements, i.e. flame atomic absorption spectroscopy (FAAS), nitrogen sorption, X-ray diffraction (XRD) and scanning electron microscopy (SEM), revealed that the so-obtained material consisted mainly of ZnMn2O4. This material acts as a heterogeneous catalyst in a Fenton-like process that degrades the dye Indigo Carmine in water. That is probably due to the presence of Mn(III) (manganese in the +3 oxidation state) in this material that triggers the decomposition of hydrogen peroxide (H2O2) to yield hydroxyl radicals (HO·). Moreover, direct infusion electrospray ionization coupled to high resolution mass spectrometry (ESI-HRMS) was employed to characterize the main by-products resulting from such degradation process. These initial results thus indicate that raw materials from waste batteries can therefore be potentially employed as efficient Fenton-like catalysts to degrade organic pollutants in an aqueous solution.

Reactions Involved in Phenolics Degradation from Sugarcane Juice Treated by Ozone

ABSTRACTOzone as an alternative process for the clarification of sugarcane juice has been studied because it presents as an advantage the mineralization of organic compounds that cause color in the crystal sugar. No residues harmful to humans were found after ozonation in contrast to the sulphitation process traditionally used. In this work, the degradation by ozonation of flavonoids and phenolic acids were studied using two compounds: rutin and caffeic acid. Ozonation was efficient and was monitored by liquid chromatography, UV scanning and direct infusion electrospray ionization mass spectrometry. From the collected data, degradation mechanisms and potential mineralization of rutin and caffeic acid after ozonation were proposed.

Liquid Extraction Surface Analysis (LESA) Electron-Induced Dissociation and Collision-Induced Dissociation Mass Spectrometry of Small Molecule Drug Compounds

Here, we present liquid extraction surface analysis (LESA) coupled with electron-induced dissociation (EID) mass spectrometry in a Fourier-transform ion cyclotron resonance mass spectrometer for the analysis of small organic pharmaceutical compounds directly from dosed tissue. First, the direct infusion electrospray ionisation EID and collision-induced dissociation (CID) behaviour of erlotinib, moxifloxacin, clozapine and olanzapine standards were compared. EID mass spectra were also compared with experimental or reference electron impact ionisation mass spectra. The results show that (with the exception of erlotinib) EID and CID result in complementary fragment ions. Subsequently, we performed LESA EID MS/MS and LESA CID MS/MS on singly charged ions of moxifloxacin and erlotinib extracted from a thin tissue section of rat kidney from a cassette-dosed animal. Both techniques provided structural information, with the majority of peaks observed for the drug standards also observed for the tissue-extracted species. Overall, these results demonstrate the feasibility of LESA EID MS/MS of drug compounds from dosed tissue and extend the number of molecular structures for which EID behaviour has been determined.Graphical ᅟ

Vacuum Matrix-Assisted Ionization Source Offering Simplicity, Sensitivity, and Exceptional Robustness in Mass Spectrometry.

Vacuum matrix-assisted ionization (vMAI) uses select matrix compounds which when exposed to the vacuum of a mass spectrometer produce gas-phase ions from associated volatile or nonvolatile analyte without external energy input. Here, a vMAI source was constructed to replace the commercial inlet of a Thermo Orbitrap mass spectrometer. This allowed for rapid introduction of the matrix/analyte sample by a probe, contrary to vacuum matrix-assisted laser desorption/ionization (MALDI) sources. The matrix/analyte sample is inserted into a region of the "S-lens" entrance, where the spontaneously formed ions can be effectively transferred to the mass analyzer. This specifically designed ion source requires no laser, high voltage, heat, or nebulizing gases. A low voltage is used to transmit the ions through the commercial "S-lens" assembly and airflow can be used to modulate the ionization event. A few picograms of the drug erythromycin, assisted by the 3-nitrobenzonitrile vMAI matrix, is sufficient to produce mass spectra for over 1 min with the MH+ ion as the base peak in each mass spectrum. There is minimal carryover when loading high concentration samples and complex mixtures, contrary to direct infusion electrospray ionization, providing the probe is thoroughly cleaned between each new sample acquisition. Analyses of biological fluids, bacterial extracts, tissue, and high concentration samples have so far shown no indication of inlet or instrument contamination with these samples. The typical ultrahigh resolution and mass accuracy of the mass spectrometer are achieved, and a path forward to potential high throughput acquisitions demonstrated. It is expected that robustness can be introduced to any mass spectrometer through implementation of such a simple source.

Phenolic Composition and Leishmanicidal Activity of Red Propolis and Dalbergia ecastaphyllum (L.) Taub (Fabaceae) Extracts from Sergipe, Brazil

ABSTRACT Leishmaniasis is a parasitic disease caused by protozoa of the Leishmania genus. It may manifest in visceral and tegumentary forms, and pentavalent antimonials are the first choice drugs used for the treatment. Frequently these drugs show low efficiency and high toxicity to mammalian host. The present study describes the chemical profile and the in vitro leishmanicidal effects of red propolis and Dalbergia ecastaphyllum extracts from Sergipe, Brazil, in Leishmania chagasi and Leishmania amazonensis promastigotes. The phenolic composition of the extracts was evaluated by direct infusion electrospray ionization mass spectrometry (ESI-MS) fingerprinting. The leishmanicidal effect was evaluated by the Resazurin colorimetric method. Similar composition profiles have been found for D. ecastaphyllum and propolis samples. The isoflavones formononetin, biochanin A, daidzein and pinocembrin were identified in both extracts. Propolis extract showed leishmanicidal activity in both L. chagasi and L. amazonensis, with IC50 values of 21.54 and 9.73 µg/mL, respectively. The D. ecastaphyllum extract presented activity only in L. amazonensis, with IC50 of 53.42 µg/mL. These results suggest that red propolis extract from Sergipe has the leguminosae D. ecastaphyllum as botanical origin, and that it presents potential leishmanicidal activity, which may be associated with the presence of the phenolic compounds found in its composition.

Persulfate initiated free-radical polymerization of itaconic acid: Kinetics, end-groups and side products

Persulfate initiated free radical homopolymerization of itaconic acid in aqueous media has been investigated at 65 °C. The research was focused on the elucidation of the chemical structure of low-molecular-weight side products and itaconic oligomers separated from polymeric fraction by dialysis (cut-off of 1000 Da). Nuclear magnetic resonance (NMR) 1H, 13C, 1H–13C me-HSQC and 1H–13C HMBC experiments and direct infusion electrospray ionization mass spectrometry (ESI-MS) operated in the negative ion mode have been combined to investigate the low-molecular fraction. It was found that 2-hydroxyparaconic and itatartaric acid are the primary oxidation products formed during free radical polymerization of itaconic acid. Besides, ESI-MS analysis revealed sulfate, hydroxyl and lactone terminal groups resulted from disproportionation, combination and transfer processes. Kinetics studies using Raman spectrometry in initiator range of 0.07–0.32 mol/L and for monomer concentration between 1.32 and 2.63 mol/L indicated non-classical dependency both polymerization rate and initiator decomposition rate on monomer and initiator concentration.

Quantitative determination of the veterinary drug monensin in horse feed samples by square wave voltammetry (SWV) and direct infusion electrospray ionization tandem mass spectrometry (DI–ESI–MS/MS)

This paper presents for the first time the determination of monensin monosodium salt (MnzNa) by means of square wave voltammetry (SWV), cyclic voltammetry (CV), and, in parallel, direct infusion electrospray ionization tandem mass spectrometry (DI–ESI–MS/MS). The influence of various factors, such as pH, buffer composition, and SWV parameters on current response was studied. The best SWV signal was obtained at about −1.50 V versus an Ag/AgCl/KCl reference electrode in Britton–Robinson (B–R) buffer. Under optimal conditions, the SWV response of the renewable silver amalgam film electrode Hg(Ag)FE was linear over two MnzNa concentration ranges, from 7.5 × 10−8 to 5.0 × 10−7 mol L−1 and from 5.0 × 10−7 to 1.0 × 10−5 mol L−1. The limits of detection and quantification were 1.27 × 10−8 mol L−1 and 4.23 × 10−8 mol L−1, respectively. The applicability of the developed SWV method was investigated in the determination of MnzNa in horse feed by the standard addition method. CV was applied to understand the electrode mechanism of MnzNa. Finally, direct infusion electrospray ionization tandem mass spectrometry (DI–ESI–MS/MS) was used to determine MnzNa in horse feed samples by the external calibration method. The detector response was linear in the concentration range of 1.1 × 10−7 to 1.4 × 10−6 mol L−1. The obtained limits of detection and quantification were 3.4 × 10−8 mol L−1 and 1.1 × 10−7 mol L−1, respectively. Statistical analysis of MnzNa determination results from SWV and DI–ESI–MS/MS did not reveal any significant differences between them.

A new processing scheme for ultra-high resolution direct infusion mass spectrometry data

High resolution, high accuracy mass spectrometry is widely used to characterise environmental or biological samples with highly complex composition enabling the identification of chemical composition of often unknown compounds. Despite instrumental advancements, the accurate molecular assignment of compounds acquired in high resolution mass spectra remains time consuming and requires automated algorithms, especially for samples covering a wide mass range and large numbers of compounds. A new processing scheme is introduced implementing filtering methods based on element assignment, instrumental error, and blank subtraction. Optional post-processing incorporates common ion selection across replicate measurements and shoulder ion removal. The scheme allows both positive and negative direct infusion electrospray ionisation (ESI) and atmospheric pressure photoionisation (APPI) acquisition with the same programs. An example application to atmospheric organic aerosol samples using an Orbitrap mass spectrometer is reported for both ionisation techniques resulting in final spectra with 0.8% and 8.4% of the peaks retained from the raw spectra for APPI positive and ESI negative acquisition, respectively.

Assessment of Adulteration of Cosmetics Based on Vegetable Oils by GC-FID and Lipid Profile Using Direct Infusion Electrospray Ionization Mass Spectrometry (ESI-MS)

Vegetable oils have properties that are beneficial to the human skin, and so, they are being used increasingly as ingredients of many cosmetic preparations; however, they are targets of adulteration. This study will evaluate the authenticity of Brazilian cosmetics based on vegetable oils (sesame, peanut, sunflower, and almonds) to determine the composition of fatty acids by gas chromatography with flame ionization detection (GC-FID) and the percentage of fatty acids in conjunction with chemometric treatments (principal component analysis), and lipid profiles using direct infusion electrospray ionization mass spectrometry (ESI-MS). The results obtained were compared with the respective pure vegetable oils. Of the seven brands analyzed, three were revealed as authentic, three were found to be adulterated with the addition of large amounts of soybean oil, and one showed no vegetable oils. These results demonstrate the relevance of quality control for cosmetics based on vegetable oils, which are more susceptible to adulteration owing to their higher cost when compared with vegetable oils such as soybean.

Combined Metabolomic Analysis of Plasma and Urine Reveals AHBA, Tryptophan and Serotonin Metabolism as Potential Risk Factors in Gestational Diabetes Mellitus (GDM).

Gestational diabetes mellitus during pregnancy has severe implications for the health of the mother and the fetus. Therefore, early prediction and an understanding of the physiology are an important part of prenatal care. Metabolite profiling is a long established method for the analysis and prediction of metabolic diseases. Here, we applied untargeted and targeted metabolomic protocols to analyze plasma and urine samples of pregnant women with and without GDM. Univariate and multivariate statistical analyses of metabolomic profiles revealed markers such as 2-hydroxybutanoic acid (AHBA), 3-hydroxybutanoic acid (BHBA), amino acids valine and alanine, the glucose-alanine-cycle, but also plant-derived compounds like sitosterin as different between control and GDM patients. PLS-DA and VIP analysis revealed tryptophan as a strong variable separating control and GDM. As tryptophan is biotransformed to serotonin we hypothesized whether serotonin metabolism might also be altered in GDM. To test this hypothesis we applied a method for the analysis of serotonin, metabolic intermediates and dopamine in urine by stable isotope dilution direct infusion electrospray ionization mass spectrometry (SID-MS). Indeed, serotonin and related metabolites differ significantly between control and GDM patients confirming the involvement of serotonin metabolism in GDM. Clustered correlation coefficient visualization of metabolite correlation networks revealed the different metabolic signatures between control and GDM patients. Eventually, the combination of selected blood plasma and urine sample metabolites improved the AUC prediction accuracy to 0.99. The detected GDM candidate biomarkers and the related systemic metabolic signatures are discussed in their pathophysiological context. Further studies with larger cohorts are necessary to underpin these observations.

Electrostatic Spray Ionization from 384-Well Microtiter Plates for Mass Spectrometry Analysis-Based Enzyme Assay and Drug Metabolism Screening.

We have realized the direct ionization of samples from wells of microtiter plates under atmospheric conditions for mass spectrometry analysis without any liquid delivery system or any additional interface. The microtiter plate is a commercially available 384-well plate without any modification, working as a container and an emitter for electrostatic spray ionization of analytes. The approach provides high throughput for the large batches of reactions and both the qualitative and quantitative analysis of a single compound or mixture. The limits of detection in small drug molecules, peptides, and proteins are similar in comparison with standard direct infusion electrospray ionization. The analysis time per well is only seconds. These analytical merits benefit many microtiter plate-based studies, such as combinatorial chemistry and high throughput screening in enzyme assay or drug metabolism. Herein, we illustrate the application in enzyme assay using tyrosine oxidation catalyzed by tyrosinase in the presence or absence of inhibitors. The potential application in drug development is also demonstrated with cytochrome P450-catalyzed metabolic reactions of two drugs in microtiter plates followed with direct ESTASI-MS/MS-based characterization of the metabolism products.

Comparison of Ambient and Atmospheric Pressure Ion Sources for Cystic Fibrosis Exhaled Breath Condensate Ion Mobility-Mass Spectrometry Metabolomics

Cystic fibrosis (CF) is an autosomal recessive disorder caused by mutations in the gene that encodes the cystic fibrosis transmembrane conductance regulator (CFTR) protein. The vast majority of the mortality is due to progressive lung disease. Targeted and untargeted CF breath metabolomics investigations via exhaled breath condensate (EBC) analyses have the potential to expose metabolic alterations associated with CF pathology and aid in assessing the effectiveness of CF therapies. Here, transmission-mode direct analysis in real time traveling wave ion mobility spectrometry time-of-flight mass spectrometry (TM-DART-TWIMS-TOF MS) was tested as a high-throughput alternative to conventional direct infusion (DI) electrospray ionization (ESI) and atmospheric pressure chemical ionization (APCI) methods, and a critical comparison of the three ionization methods was conducted. EBC was chosen as the noninvasive surrogate for airway sampling over expectorated sputum as EBC can be collected in all CF subjects regardless of age and lung disease severity. When using pooled EBC collected from a healthy control, ESI detected the most metabolites, APCI a log order less, and TM-DART the least. TM-DART-TWIMS-TOF MS was used to profile metabolites in EBC samples from five healthy controls and four CF patients, finding that a panel of three discriminant EBC metabolites, some of which had been previously detected by other methods, differentiated these two classes with excellent cross-validated accuracy. Graphical Abstract ᅟ.

HPLC–DAD Method for Simultaneous Determination of Dipyrone (Metamizole) and Caffeine in Tablets and Identification of Major Degradation Product by Direct Infusion ESI–MS

A new chromatographic method for simultaneous determination of dipyrone (metamizole) and caffeine in tablets was developed and validated. Excellent resolution and quantification were obtained using a reverse-phase Acclaim® C18 column (250.0 × 4.6 mm; 5.0 μm particles) with acetonitrile/water (65:35 v/v) as mobile phase, adjusted to pH 7.5 using drops of water:triethylamine (99:1 v/v). The elution mode was isocratic with flow rate of 1.0 mL min−1, and ultraviolet (UV) detection was performed at 273 nm. The ranges of linearity for dipyrone and caffeine were 5.0–35.0 and 1.0–7.0 μg mL−1, respectively. Intra- and interday precision showed relative standard deviation (RSD) 0.05, respectively. The method proved to be precise, sensitive, and exact with low limits of detection and quantification and average recovery of 99.3 and 100.8%. The factorial model of Youden was used to analyze the robustness of the method, while identification of critical factors was conducted by two-tailed t test with 95% confidence interval. The method was shown to be selective, detecting presence of analytes in degradation products originating from study of hydrolytic stability at different pH values (5.0, 6.0, 7.0, and 9.0) at room temperature. Identification of product degradation by direct injection electrospray ionization (ESI) mass spectroscopy (MS) revealed the presence of a fragment ion at m/z 187 and ions corresponding to [M + H]+ and [M + Na]+ at m/z 218 and 240, respectively, confirming the identity of the 4-methylaminoantipyrine product related to dipyrone.

Characterisation of captopril photolysis and photocatalysis by-products in water by direct infusion, electrospray ionisation, high-resolution mass spectrometry and the assessment of their toxicities

ABSTRACTPharmaceuticals of different therapeutic classes are found in the environment. Captopril is used worldwide as an antihypertensive drug, and it has been found in the influent, effluent and secondary sludge of wastewater treatment plants. Advanced oxidation processes, such as direct photolysis (UV-C) and heterogeneous photocatalysis (TiO2/UV-C), are alternatives to enhance mineralisation of pharmaceuticals and their removal during water treatment. In this article, it was evaluated the degradation of captopril in aqueous solution induced by UV-C and TiO2/UV-C systems. The process focused on the identification and monitoring of the by-products formed under these conditions by applying direct-infusion electrospray ionisation high-resolution mass spectrometry in the negative ion mode (ESI(-)-HRMS) and high-performance liquid chromatography coupled to high-resolution mass spectrometry (HPLC/HRMS). To evaluate the by-products toxicity, acute ecotoxicity tests were performed with the crustacean Artemia salina, and the cytotoxicity was evaluated with (4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay using HepG2 cells. It was observed by ESI(-)-HRMS that after 120 min of light exposure, there was almost complete removal of captopril, with 93.5% removal efficiency during photolysis and 99.9% during photocatalysis. At these conditions, the rate of mineralisation, by total organic carbon (TOC), was only 2.92% for photolysis and 9.09% for photocatalysis, evidencing the formation of degradation by-products. Nine by-products of captopril photodegradation were identified, and their respective chemical structure elucidations were proposed. The treated samples were nontoxic to A. salina and HepG2 cells, indicating that both oxidative treatments (photocatalytic or photolytic processes) can be conveniently employed to remove captopril from aqueous media.

Plug-Volume-Modulated Dilution Generator for Flask-Free Chemistry.

Dilution is one of the common chemical procedures which are carried out in all chemistry laboratories-to prepare standard solutions with different concentrations for assay calibration, and to reduce matrix effects while handling complex samples. Yet dilution is mostly performed manually using large-volume manual liquid-handling tools (volumetric flasks, graduated cylinders, and pipettes). Here we describe a simple continuous and automated method of diluting complex samples and stock solutions using an Arduino-based control unit. The proposed plug-volume-modulation approach relies on continuous introduction of short plugs of samples separated with short plugs of solvent. The train of sample pulses is generated by opening and closing two pinch valves interchangeably, so that either sample or solvent can enter the mixing zone (T-junction). The plugs of sample and solvent are pulled along a transfer flow line by a peristaltic pump. They mix due to advection, turbulence, and diffusion. The effluent of the flow line supplies diluted samples with well-defined dilution factors. The desired dilution factor is programmed by setting the duration of sample and solvent pulses injected in every cycle. The sample duty cycle effectively determines the dilution factor. Initially, we verified the quality of the generated diluted samples by off-line and online optical detection. We further demonstrated the usefulness of this dilution generator when selecting the optimum dilution factors for complex samples analyzed by direct infusion electrospray ionization mass spectrometry. The proposed method eliminates conventional glassware from dilution steps. Hence, it can readily be incorporated into automated analytical systems.

Preconcentration of organic solutes in urine by bubble bursting

The chemical sensitivity of urine metabolomics analysis is greatly compromised due to the large amounts of inorganic salts in urine (NaCl, KCl), which are detrimental to analytical instrumentation, e.g. chromatographic columns or mass spectrometers. Traditional desalting approaches applied to urine pretreatment suffer from the chemical losses, which reduce the information depth of analysis. We aimed to test a simple approach for the simultaneous preconcentration and desalting of organic solutes in urine based on the collection of induced bursting bubble aerosols above the surface of urine samples. Bursting bubbles were generated at ambient conditions by feeding gas through an air diffuser at the bottom of diluted (200 times in ultrapure water) urine solution (50–500 mL). Collected aerosols were analyzed by the direct-infusion electrospray ionization mass spectrometry (ESI–MS). The simultaneous preconcentration (ca. 6–12 fold) and desalting (ca. six–tenfold) of organic solutes in urine was achieved by the bursting bubble sample pretreatment, which allowed ca. three-times higher number of identified urine metabolites by high-resolution MS analysis. No chemical losses due to bubbling were observed. The increased degree of MS data clustering was demonstrated on the principal component analysis of data sets from the urine of healthy people and from the urine people with renal insufficiency. At least ten times higher sensitivity of trace drug detection in urine was demonstrated for clenbuterol and salbutamol. Our results indicate the high versatility of bubble bursting as a simple pretreatment approach to enhance the chemical depth and sensitivity of urine analysis. The approach could be attractive for personalized medicine as well as for the diagnostics of renal disorders of different etiology (diabetic nephropathy, chronic renal failure, transplant-associated complications, oncological disorders). Urine desalting and preconcentration in bursting bubbles.

Compositional Analysis of Wax Esters in Human Meibomian Gland Secretions by Direct Infusion Electrospray Ionization Mass Spectrometry.

Wax esters (WE) are one of the predominant lipid types in human meibomian gland secretions (meibum) and account for 40-50% of total meibum lipids. Recently, we managed to quantify 51 isomeric groups of intact WE in normal human meibum samples by direct infusion electrospray ionization mass spectrometry (ESI-MS), with each WE peak in the MS spectrum corresponding to one isomeric group (Chen et al, Invest Ophthalmol Vis Sci 54(8):5730-53, 2013). However, the information of the isomeric composition in each group was not obtained. In this study, tandem mass spectrometry (MS/MS) was applied to quantify relative amounts of these isomers using the intensities of the corresponding diagnostic ions after appropriate correction and normalization. This data was combined with the previous obtained mole fraction of each isomeric group to total WE in human meibum to determine the corresponding percentage of each isomer. A total of 23 of the most abundant WE peaks of different molecular weights (corresponding to 85.3% of the total amount of WE) in human meibum were studied and resulted in quantification of 92 WE species. The quantitative information of composition of WE in human meibum will help better understand their role in the tear film.

Quantitative analysis of biogenic polyamines in distilled drinks by direct electrospray ionization tandem mass spectrometry using a nanocontainer.

Biogenic polyamines in drinks have been implicated in undesirable physiological effects. Methods for their detection and quantification usually involve derivatization, pre-concentration and clean-up. To assist the evaluation of the potential risk of distillates, it was important to develop a simple and fast analytical method, which is described in this study. Biogenic polyamines were selectively encapsulated after addition of a nanocontainer, cucurbit[7]uril (50μM), to the distilled drink samples, which were acidified with HCl (pH3) prior addition of the nanocontainer. The quantification of polyamines was achieved by direct infusion electrospray ionization quadrupole ion trap mass spectrometry in the multiple reaction monitoring mode, using encapsulated amantadine as internal standard, and by monitoring signals originating from their host-guest complexes. Six point calibration curves, ranging from 0.5μM to 20μM of polyamines in water and ethanol/water (50:50), were used to establish instrument response. The method was validated by analysis of fortified Arbutus spirits. Samples of Arbutus and grape pomace spirits were also analyzed. Linear responses were observed for all polyamines and were similar in water, hydro-alcoholic solutions and fortified Arbutus spirits. Putrescine the simple polyamine was detected only in grape pomace distillate samples. A quantitative method was developed for rapid and simple analysis of biogenic polyamines in distilled drinks. The detection limits depend on the ionization properties of the samples. Encapsulated amantadine can be used to probe these properties and method application. Copyright © 2016 John Wiley & Sons, Ltd.

Chemical characterization of synthetic cannabinoids by electrospray ionization FT-ICR mass spectrometry

The synthetic cannabinoids (SCs) represent the most recent advent of the new psychotropic substances (NPS) and has become popularly known to mitigate the effects of the ο9-THC. The SCs are dissolved in organic solvents and sprayed in a dry herbal blend. However, little information is reported on active ingredients of SCs as well as the excipients or diluents added to the herbal blend. In this work, the direct infusion electrospray ionization Fourier transform ion cyclotron mass spectrometry technique (ESI-FT-ICR MS) was applied to explore the chemical composition of nine samples of herbal extract blends, where a total of 11 SCs (UR-144, JWH-073, XLR-11, JWH-250, JWH-122, AM-2201, AKB48, JWH-210, JWH-081, MAM-2201 and 5F-AKB48) were identified in the positive ionization mode, ESI(+), and other 44 chemical species (saturated and unsaturated fatty acids, sugars, flavonoids, etc.) were detected in the negative ionization mode, ESI(⿿). Additionally, CID experiments were performed, and fragmentation pathways were proposed to identify the connectivity of SCs. Thus, the direct infusion ESI-FT-ICR MS technique is a powerful tool in forensic chemistry that enables the rapid and unequivocal way for the determination of molecular formula, the degree of unsaturation (DBE⿿double bond equivalent) and exact mass (<1ppm) of a total of 55 chemical species without the prior separation step.

Letter: Comparison of pyridine and pyrazine derivatives distributions in exhaled breath and exhaled breath condensate after smoking.

Molecular mass distributions of series of compounds found in exhaled breath after smoking are compared between the direct-breath analysis by extractive electrospray ionization and the analysis of exhaled breath condensate by direct-infusion electrospray ionization mass spectrometry. Although all the analyzed series of compounds are detected by both methods, their relative abundances are different. A number-average mass is used as a quantitative characteristic of the series. It is shown that this value is close for the distributions of the series of compounds in the mass spectrum of exhaled breath condensate and the mass spectrum obtained by summation of direct mass spectra over the breathing time.