Elemental Composition of Commercially Available Cannabis Rolling Papers.

With the recent legalization of cannabis in multiple jurisdictions and widespread use as a medical treatment, there has been an increased focus on product safety and the potential impacts of contaminants on human health. One factor that has received little attention is the possible exposure to potentially hazardous levels of toxic elements from rolling (smoking) papers. The elemental composition of rolling papers is largely unregulated, with a minority of jurisdictions regulating papers only when they are part of a final cannabis product. This study reports the concentrations of 26 elements in commercially available rolling papers and estimates potential maximum exposures relative to USP232 and ICH Q3D dosages in pharmaceutical compounds. Exposure estimates indicate that the concentrations of several elements in some products, particularly Cu, Cr, and V, may present a potential hazard to frequent users. Several elements, including Ag, Ca, Ba, Cu, Ti, Cr, Sb, and possibly others, are likely present in elevated quantities in some papers due to product design and manufacturing processes. Our results further suggest that Cu-based pigments are used by a number of manufacturers and that regular use of these products might result in exposures as high as 4.5-11 times the maximum exposure limits. Further research to quantify the contribution of rolling papers to elemental exposure under realistic smoking conditions is warranted.

Selective Sampling to and Desorption from Single Solid-Phase Microextraction Arrow Fiber for Replicative and Quantitative Analysis.

New analytical functionality is demonstrated with an enclosed interface that joins a solid phase microextraction (SPME) device, a direct analysis in real time (DART) probe, and a high-resolution mass spectrometer. With a single 20 mm long SPME Arrow, the interface is able to perform five discrete DART analyses on different areas of the same fiber in 1 min of practical operation time. Three-fiber replicates for 15 runs total produce 15% or better center of variance (CV) values for both volatile headspace sampling and direct immersion sampling of a solvated analyte. Chemometric analysis of rapidly acquired headspace data is able to distinguish volatile profiles. Selective desorption within the interface also confers the ability to selectively sample to discrete areas of a fiber, and three different headspace samples or five different liquid samples can be acquired and differentiated with one Arrow. A five-point standard addition curve is constructed to measure the concentration of the solvated analyte. Unmodified commercial components of the analysis system include the fiber itself, the Orbitrap and AccuTOF mass spectrometer platforms, and the conditioning gas chromatograph inlet. Machine diagrams for the SPME-DART interface and Arrow fiber holder are included.

Method development for forensic oil identification by direct analysis in real time time-of-flight mass spectrometry.

The current well-established chromatography and mass spectrometry based oil spill identification procedures, such as those outlined by the European Committee for Standardization, are highly reliable as methods, highly defensible in the court of law, and widely applicable to the majority of oil spill situations. Nevertheless, the methodology is time consuming and labour intensive, which may not be ideal when dealing with an emergency oil spill situation. In this study, direct analysis in real time time-of-flight mass spectrometry (DART/TOFMS) was used to successfully develop an efficient oil identification method. To confirm the accuracy of this method spilled oil samples were tested from five previous years of blind round robin testing organized by the oil spill identification network of experts (OSINET) under the Bonn Agreement. Heatmap inspection, principal component analysis and finally discriminant analysis of principal components were used to arrive at final predictions regarding the identities of the spilled oil samples. The results were compared with the results of previous gas chromatography flame ionization detection (GC/FID) and gas chromatography triple quadrupole mass spectrometry (GC/MS/MS) analyses of the same oils. While taking only about a tenth of the time, the DART/TOFMS analysis produced results similar to those of classical GC/FID and GC/MS/MS (EI+) procedures. The ability of DART/TOFMS to display this level of validity exemplifies its potential to be a new tool for supplementing classical analyses for oil spill forensics.

Wood from Hardwood Angiosperms and Coniferous Gymnosperms Shows Distinctive Lignin Peaks in Direct Analysis in Real Time (DART) Mass Spectra.

A data set was constructed consisting of 3021 mass spectra randomly selected from all available families in the ForeST© (Forensic Spectra of Trees) database of mass spectra for wood analyzed by Direct Analysis in Real Time ionization coupled with time-of-flight mass spectrometry (DART-TOFMS). Clear and reproducible differences were observed between the lignin peaks for hardwood angiosperms and coniferous gymnosperms, with DART-TOFMS spectra of angiosperms showing significantly higher relative abundances for peaks associated with syringyl subunits. Application of the method to processed wood samples demonstrated that these differences can be used to provide support for enforcing trade laws by accurately identifying the source of finished wood products from hardwood angiosperms and coniferous gymnosperms.

Aperture Size Influences Oxidation in Positive-Ion Nitrogen Direct Analysis in Real Time Mass Spectrometry.

Direct Analysis in Real Time (DART) mass spectrometry commonly uses helium as the DART gas. With the looming helium shortage, other gases are being evaluated for DART. Nitrogen is inexpensive and readily available, making it a desirable alternative. However, NO+ reagent ions present in positive-ion nitrogen DART result in extensive oxidation for many compounds. The DART source uses a ceramic insulator cap to protect the operator from electrical shock. The most common cap has an aperture with a 2.5 mm inner diameter, through which the gas exits the DART source. By using a cap with a narrow (0.5 mm) ID, oxidation can be significantly reduced for nitrogen DART. The 0.5 mm cap is hypothesized to reduce back-diffusion of atmospheric oxygen into the DART source, with a reduction in the relative abundance of NO+ and increase in the relative abundance of [(H2O)2 + H]+ as the reactive species responsible for ionization of the analytes.

Creating a Searchable Chromatographic Database with the NIST Mass Spectral Search Program.

The NIST Mass Spectral Search Program can be used to create a searchable database of chromatograms. This approach was tested for a small database of chromatograms for gin volatiles and for a database of insect cuticular hydrocarbons with retention times and reconstructed total ion current chromatographic peak areas substituted for m/z values and abundance. The In-source HiRes Identity search permitted matching of randomly selected chromatograms against the database with good results. This approach is not intended to replace commercial software for chromatographic database management as it does not address the problems of chromatographic alignment or chromatographic deconvolution, but it does provide a method to manage a simple chromatographic database if other options are not available.

Cuticular hydrocarbons for the identification and geographic assignment of empty puparia of forensically important flies.

Research in social insects has shown that hydrocarbons on their cuticle are species-specific. This has also been proven for Diptera and is a promising tool for identifying important fly taxa in Forensic Entomology. Sometimes the empty puparia, in which the metamorphosis to the adult fly has taken place, can be the most useful entomological evidence at the crime scene. However, so far, they are used with little profit in criminal investigations due to the difficulties of reliably discriminate among different species. We analysed the CHC chemical profiles of empty puparia from seven forensically important blow flies Calliphora vicina, Chrysomya albiceps, Lucilia caesar, Lucilia sericata, Lucilia silvarum, Protophormia terraenovae, Phormia regina and the flesh fly Sarcophaga caerulescens. The aim was to use their profiles for identification but also investigate geographical differences by comparing profiles of the same species (here: C. vicina and L. sericata) from different regions. The cuticular hydrocarbons were extracted with hexane and analysed using gas chromatography-mass spectrometry. Our results reveal distinguishing differences within the cuticular hydrocarbon profiles allowing for identification of all analysed species. There were also differences shown in the profiles of C. vicina from Germany, Spain, Norway and England, indicating that geographical locations can be determined from this chemical analysis. Differences in L. sericata, sampled from England and two locations in Germany, were less pronounced, but there was even some indication that it may be possible to distinguish populations within Germany that are about 70 km apart from one another.

Mass Defect Filter for Removing Noise and Detector Oscillation Artifacts in Centroided Time-of-Flight Mass Spectra.

Spurious peaks in centroided mass spectra resulting from detector oscillation or "ringing" can be identified by their unusual mass defects. Mass defect plots (fractional m/z vs measured m/z) for the single-charge mass spectrum of a pure compound show data points falling along lines with well-defined slopes. Detector oscillation and electronic noise peaks were removed from database spectra of pure compounds and mixtures by eliminating points outside two standard deviations of the slope of the major peaks. No loss of chemical information was observed, even for compounds with isobaric fragment peaks.

Fast pesticide analysis using low-pressure gas chromatography paired with a triple quadrupole mass spectrometer equipped with short collision cell technology.

RATIONALE: A proof of concept showing GC-MS/MS analysis time for pesticides can be dramatically reduced while maintaining a similar separation efficiency by combining a low-pressure gas chromatography (LPGC) column with the enhanced selected reaction monitoring (SRM) switching speed of the short collision cell of a JEOL JMS-TQ4000GC. METHODS: Triple-quadrupole tandem mass spectrometry (standard EI + at 70 eV) was used to measure pesticides eluting from a low-pressure gas chromatograph capillary column. Three transitions for each of 244 pesticide compounds were measured within an 11-min analysis time, and the data were checked to confirm the method's reproducibility and ability to distinguish all three transitions for each pesticide. RESULTS: All three transitions for all 244 pesticides were detected in the standard mixture at 1X concentration within the 11-min analysis time. Relative standard deviation (RSD) of peak areas was less than 15% for 242 pesticides, and I/Q RSDs were less than 10% for 242 compounds. Retention time RSD over 15 replicates was less than 0.1%. CONCLUSIONS: Results show that analysis time can be markedly decreased using an LPGC column, and that the ability of the short collision cell to distinguish a large number of coeluting peaks makes the two technologies a natural pairing. The effective measurement of pesticides within a short time could benefit any scientists doing pesticide analysis work.

Two-Dimensional Gas Chromatographic and Mass Spectrometric Characterization of Lipid-Rich Biological Matrices-Application to Human Cerumen (Earwax).

Earwax is a readily accessible biological matrix that has the potential to be used in disease diagnostics. However, its semisolid nature and high chemical complexity have hampered efforts to investigate its potential to reveal disease markers. This is because more conventional methods of analysis such as gas chromatography-mass spectrometry (GC-MS) and liquid chromatography-mass spectrometry yield unsatisfactory results due to the presence of many nonvolatile and/or coeluting compounds, which in some cases have very similar mass spectrometric profiles. In addition, these routine methods often require the sample to be saponified, which dramatically increases the complexity of the analysis and makes it difficult to determine which compounds are actually present versus those that are produced by saponification. In this study, two-dimensional GC mass spectrometry (GC × GC-MS) was successfully applied for the characterization of the chemical components of earwax from healthy donors using nonpolar (primary) and midpolar (secondary) columns without saponification. Over 35 of the compounds that were identified are reported for the first time to be detected in unsaponified earwax. The resulting GC × GC-MS contour plots revealed visually recognizable compound class clusters of previously reported groups including alkanes, alkenes, fatty acids, esters, triglycerides, and cholesterol esters, as well as cholesterol and squalene. The application of GC × GC-MS revealed results that provide a foundation upon which future studies aimed at comparing healthy donor earwax to that from individuals exhibiting various disease states can be accomplished.

Integrated data analysis making use of the total information from gas chromatography and high-resolution time-of-flight mass spectrometry to identify qualitative differences between two whisky samples.

RATIONALE: Analysis of complex mixtures with gas chromatography coupled with high-resolution time-of-flight mass spectrometry (GC/HRTOFMS) can produce a large amount of data. A new software program was recently reported that integrates all of the available mass spectrometric information from GC/HRTOFMS analysis into a concise report. New capabilities have now been added to the software to incorporate retention index data and to identify differences between two samples. METHODS: Two Scotch whisky samples were sampled by solid-phase microextraction (SPME) and analyzed by GC/HRTOFMS. One of the two whisky samples (Sample B) was identical to the other sample (Sample A) except for an additional 6-months storage in sherry casks. Both electron ionization (EI) and chemical ionization (CI) data were obtained using a new GC/TOFMS system (JEOL AccuTOF GC-Alpha) with enhanced resolving power and mass accuracy. Statistical analysis of replicate measurements of the whisky samples was carried out with a new software program (msFineAnalysis version 3.2) to identify and assign differences between the samples. RESULTS: There were 124 peaks detected in the two whiskies. Thirteen compounds were detected with a relative peak area greater than 0.05% that were present in greater amounts in the whisky that had been stored in sherry casks for an additional 6 months. Ten of these compounds were identified by the software with high confidence, two were identified as isomers with close retention indices, and one was identified interactively. CONCLUSIONS: The software identified small differences between the two samples that resulted from sherry cask aging. Because all of the information available from the hard and soft ionization analyses for each compound is summarized in a concise integrated report, the operator can rapidly determine the level of confidence for each assignment and inspect the information for compounds that are not present in the database.

Qualitative Analysis of Acid Salts with Direct Analysis in Real Time Mass Spectrometry by Conversion to the Free Acid Form.

Organic acid salts typically have very low volatility and are not well suited for analysis by Direct Analysis in Real Time mass spectrometry (DART-MS). However, qualitative analysis of organic acid salts by DART can be facilitated by the addition of a strong acid to convert the compounds to the free acid form. Examples are presented here for inorganic salts (sodium and potassium perchlorate) and several organic salts, including three disodium salts and a mixed sodium/potassium salt.

Cuticular hydrocarbons for identifying Sarcophagidae (Diptera).

The composition and quantity of insect cuticular hydrocarbons (CHCs) can be species-specific as well as sexually dimorphic within species. CHC analysis has been previously used for identification and ageing purposes for several insect orders including true flies (Diptera). Here, we analysed the CHC chemical profiles of adult males and females of eleven species of flesh flies belonging to the genus Sarcophaga Meigen (Sarcophagidae), namely Sarcophaga africa (Wiedemann), S. agnata Rondani, S. argyrostoma Robineau-Desvoidy, S. carnaria (Linnaeus), S. crassipalpis Macquart, S. melanura Meigen, S. pumila Meigen, S. teretirostris Pandellé, S. subvicina Rohdendorf, S. vagans Meigen and S. variegata (Scopoli). Cuticular hydrocarbons extracted from pinned specimens from the collections of the Natural History Museum, London using a customised extraction technique were analysed using Gas Chromatography-Mass Spectrometry. Time of preservation prior to extraction ranged between a few weeks to over one hundred years. CHC profiles (1) allowed reliable identification of a large majority of specimens, (2) differed between males and females of the same species, (3) reliably associated males and females of the same species, provided sufficient replicates (up to 10) of each sex were analysed, and (4) identified specimens preserved for up to over one hundred years prior to extraction.

Coated glass capillaries as SPME devices for DART mass spectrometry.

RATIONALE: Solid-phase microextraction (SPME) provides high-throughput sample cleanup and pre-concentration. Here we demonstrate coated glass capillaries (CGCs) as SPME devices for specific applications in direct analysis in real time (DART) mass spectrometry, referred to as "CGC-DART", for rapid screening of environmental contaminants at low parts-per-trillion detection limits and with accurate identification of analytes. METHODS: The extraction is performed in a one-step process in minutes by dipping the CGC in solutions containing the analytes, and then placing the CGC in a DART source for analysis. CGCs are disposable and relatively inexpensive in comparison with SPME devices, and can be prepared with hydrophobic, hydrophilic or mixed-mode materials similar to SPME. CGCs were prepared by adsorption coating with incubation of capillaries in saturated solutions of octadecylamine or covalent activation of silanes. RESULTS: Quantitation is shown with perfluorooctanoic acid (PFOA) at 1 ppt to 100 ppb, with the lowest detection at 500 parts-per quadrillion (ppq) in tap water. One-step extraction of contaminated groundwater from Northern Queensland, Australia, revealed perfluorooctane sulfonate (PFOS) and perfluorohexanesulfonamide as well as C4-C8 perfluoroalkyl carboxylic acids. A soil sample taken near a former military air base (New Hampshire, USA) revealed the presence of perfluorononanoic acid (PFNA) at 1 ppb and traces of perfluoroheptanoic acid. CONCLUSIONS: CGC-DART enabled one-step extraction of PFASs in minutes with mL sample volumes at low concentrations as shown for the standards and contaminated soil and water samples. DART-MS combined with Kendrick mass defect analysis enabled accurate identification of PFASs without chromatography steps, as fluorinated compounds are mass deficient and easily distinguished over background signal.

Integrated qualitative analysis of polymer sample by pyrolysis-gas chromatography combined with high-resolution mass spectrometry: Using accurate mass measurement results from both electron ionization and soft ionization.

RATIONALE: Gas chromatography/mass spectrometry (GC/MS) is a powerful analytical tool used to separate and then identify volatile compounds through library database searches. However, as not all compounds are registered in these databases, it is not uncommon to detect unregistered components. Therefore, new analytical techniques were developed that utilize methods of identification beyond database searches alone. METHODS: Acquire data by using electron ionization (EI) and soft ionization (SI) with high-resolution mass spectrometry (HRMS). Use the EI mass spectra to library search for matches. Use the SI mass spectra for accurate mass analysis of the EI molecular ions. Conduct an isotope pattern analysis of the molecular ion to refine the possible candidate compositions. Use these compositions as a constraint for the accurate mass analysis of the EI fragment ions. If a given molecular ion formula is not correct, the EI fragment ions will not show good matches. Finally, all analytical results are integrated into a color-coded qualitative analysis report. RESULTS: The capabilities of this new integrated analytical method were assessed for a polymer resin sample that was measured by using pyrolysis-gas chromatography/high resolution time-of-flight mass spectrometry. A total of 161 compounds were detected in the total ion current chromatogram, and 154 of these compounds were identified as having only one chemical formula candidate with this new integrated qualitative analysis method. CONCLUSIONS: This new integrated qualitative analysis method gives analytical results independent of library search results. It can be applied to a variety of SI methods including chemical ionization, photoionization, field ionization, and low-energy EI.

Rapid Fingerprinting of High-Molecular-Weight Polymers by Laser Desorption-Ionization Using Through-Hole Alumina Membrane High-Resolution Mass Spectrometry.

Residual acid found in the desorption ionization using through-holes alumina membranes (DIUTHAME) induces a reproducible protonation/in-source dissociation of polymers made of ester, amide, or siloxane moieties during their surface-assisted laser desorption ionization (SALDI) mass analysis. Deposited on the DIUTHAME chips in solution (solvent-based) or in pure form by melting the polymer powder in situ (solvent-free), high-molecular-weight nylons, silicone, or functionalized celluloses among other polymers are instantly fingerprinted by laser DIUTHAME high-resolution mass spectrometry (MS) with specific patterns resembling their direct analysis in real-time (DART) single-stage or tandem mass spectra. Depending on the polymer, two main types of fingerprints are observed with either the protonated monomer or product ions revealing the nature of the repeating unit or its functionalization. This technique allows a rapid molecular analysis of industrial homopolymers regardless of their molecular weight and complementary to DART with simple or no sample preparation and also promisingly applicable for copolymers.

Saccharomyces cerevisiae and S. pastorianus species and strain differentiation by direct analysis in real time time-of-flight mass spectrometry.

RATIONALE: Seventeen different dried yeast strains, including twelve strains of Saccharomyces cerevisiae and five strains of S. pastorianus, were analyzed using direct analysis in real time (DART) time-of-flight mass spectrometry. The resulting mass spectra were used for rapid species and strain differentiation based upon small-molecule metabolomic profiles. METHODS: Yeast strains purchased from local shops were suspended in a 1:1 water-methanol solution. Solutions were sampled by dipping the sealed end of a melting point capillary into each vial. Six replicates were measured in positive-ion and negative-ion mode for each strain using an automated linear rail with the DART source operated with helium gas and a gas heater temperature of 350°C. Averaged and centroided mass spectra were exported for analysis with chemometric software. RESULTS: Negative-ion DART mass spectra exhibited less chemical background and more distinctive components than positive-ion DART mass spectra. An on-line search of the Yeast Metabolome Database provided candidate metabolites for selection as features for chemometric analysis. Negative-ion DART mass spectra could distinguish both species and all strains. The DART analysis was also able to identify potential metabolomic differences between top-fermenting and bottom-fermenting yeast, between beer and baking yeast, and between red wine and champagne yeast. CONCLUSIONS: All strains could be distinguished by their negative-ion DART mass spectra with 97.7% validation accuracy. Clear differences were observed between dry and liquid forms and Saccharomyces strains with different applications to baking or beverage fermentation. Possible differences in metabolite profiles were suggested, but not confirmed, by accurate mass data.

Thermal desorption and pyrolysis direct analysis in real time mass spectrometry for qualitative characterization of polymers and polymer additives.

RATIONALE: Direct analysis in real time mass spectrometry (DART-MS) provides qualitative information about additives and polymer composition. However, the observed mass spectra are dependent on sampling conditions, in particular the DART gas temperature. This report describes the combination of a heated sample stage with DART-MS for polymer characterization. METHODS: Industrial polymers with different compositions were examined by thermal desorption and pyrolysis (TDPy) DART. Samples were heated on disposable copper stages from ambient temperature to 600°C, and the evolved gases were introduced directly into a DART ion source through a glass tee. Time- and temperature-dependent mass spectra were acquired using a high-resolution time-of-flight mass spectrometer. Kendrick mass analysis was applied to the interpretation of complex mass spectra observed for fluorinated polymers. RESULTS: Positive-ion DART mass spectra of common polymers exhibited peak series differing by monomer masses, often accompanied by a peak corresponding to the protonated monomer. Even polymers that did not exhibit a clear series of peaks produced characteristic mass spectra. Positive-ion and negative-ion mass spectra were recorded for fluorinated polymers, with polytetrafluoroethylene (PTFE) producing only negative ions. Thermal desorption provided characteristic temperature profiles for volatile species such as polymer additives and polymer pyrolysis products. CONCLUSIONS: In comparison with direct analysis by positioning sample directly in the heated DART gas stream, TDPy DART provides a more versatile sampling method and provides thermal separation and profiling of polymer additives, intact short polymer chains, and pyrolysis fragments.

Carbon-carbon double bond position elucidation in fatty acids using ozone-coupled direct analysis in real time mass spectrometry.

The carbon-carbon double bond positions of unsaturated fatty acids can have markedly different effects on biological function and also serve as biomarkers of disease pathology, dietary history, and species identity. As such, there is great interest in developing methods for the facile determination of double bond position for natural product chemistry, the pharmaceutical industry, and forensics. We paired ozonolysis with direct analysis in real time mass spectrometry (DART MS) to cleave and rapidly identify carbon-carbon double bond position in fatty acids, fatty alcohols, wax esters, and crude fatty acid extracts. In addition, ozone exposure time and DART ion source temperature were investigated to identify optimal conditions. Our results reveal that brief, offline exposure to ozone-generated aldehyde and carboxylate products that are indicative of carbon-carbon double bond position. The relative abundance of diagnostic fragments quantitatively reflects the ratios of isobaric fatty acid positional isomers in a mixture with a correlation coefficient of 0.99. Lastly, the unsaturation profile generated from unfractionated, fatty acid extracts can be used to differentiate insect species and populations. The ability to rapidly elucidate lipid double bond position by combining ozonolysis with DART MS will be useful for lipid structural elucidation, assessing isobaric purity, and potentially distinguishing between animals fed on different diets or belonging to different ecological populations.