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Human exposures to fentanyl analogs, which significantly contribute to the ongoing U.S. opioid overdose epidemic, can be confirmed through the analysis of clinical samples. Our laboratory has developed and evaluated a qualitative approach coupling liquid chromatography and quadrupole time-of-flight mass spectrometry (LC-QTOF) to address novel fentanyl analogs and related compounds using untargeted, data-dependent acquisition. Compound identification was accomplished by searching against a locally-established mass spectral library of 174 fentanyl analogs and metabolites. Currently, our library can identify 150 fentanyl-related compounds from the Fentanyl Analog Screening (FAS) Kit), plus an additional 25 fentanyl-related compounds from individual purchases. Plasma and urine samples fortified with fentanyl-related compounds were assessed to confirm the capabilities and intended use of this LC-QTOF method. For fentanyl, 8 fentanyl-related compounds and naloxone, lower reportable limits (LRL100), defined as the lowest concentration with 100 % true positive rate (n = 12) within clinical samples, were evaluated and range from 0.5 ng/mL to 5.0 ng/mL for urine and 0.25 ng/mL to 2.5 ng/mL in plasma. The application of this high resolution mass spectrometry (HRMS) method enables the real-time detection of known and emerging synthetic opioids present in clinical samples.

To combat the ongoing opioid epidemic, our laboratory has developed and evaluated an approach to detect fentanyl analogs in urine and plasma by screening LC-QTOF MS/MS spectra for ions that are diagnostic of the core fentanyl structure. MS/MS data from a training set of 142 fentanyl analogs were used to select the four product ions and six neutral losses that together provided the most complete coverage (97.2%) of the training set compounds. Furthermore, using the diagnostic ion screen against a set of 49 fentanyl analogs not in the training set resulted in 95.9% coverage of those compounds. With this approach, lower reportable limits for fentanyl and a subset of fentanyl-related compounds range from 0.25 to 2.5 ng/mL in urine and 0.5 to 5.0 ng/mL in plasma. This innovative processing method was applied to evaluate simulated exposure samples of remifentanil and carfentanil in water and their metabolites remifentanil acid and norcarfentanil in urine. This flexible approach enables a way to detect emerging fentanyl analogs in clinical samples.

Because the rate of naphthenic acid corrosion does not correlate with the concentration of acids, it has been proposed that a subset of naphthenic acids in petroleum fractions may be more corrosive...

We report chemical characterization of natural oil seeps from the Gulf of Mexico by Fourier transform ion cyclotron resonance mass spectrometry (FT-ICR MS) and Gas Chromatography/Atmospheric Pressure Chemical Ionization Mass Spectrometry (GC/APCI-MS), to highlight how FT-ICR MS can also be employed as a means to determine petroleum connectivity, in addition to traditional GC/MS techniques. The source of petroleum is the Green Canyon (GC) 600 lease block in the Gulf of Mexico. Within GC600, two natural oil seepage zones, Mega Plume and Birthday Candles, continuously release hydrocarbons and develop persistent oil slicks at the sea surface above them. We chemically trace the petroleum from the surface oil slicks to the Mega Plume seep itself, and further to a petroleum reservoir 5 km away in lease block GC645 (Holstein Reservoir). We establish the connectivity between oil samples and confirm a common geological origin for the oil slicks, oil seep, and reservoir oil. The ratios of seven common petroleum biomarkers detected by GC/APCI-MS display clear similarity between the GC600 and GC645 samples, as well as a distinct difference from another reservoir oil collected ∼300 km away (Macondo crude oil from MC252 lease block). FT-ICR MS and principal component analysis (PCA) demonstrate further similarities between the GC600 and GC645 samples that distinctly differ from MC252. A common geographical origin is postulated for the GC600/GC645 samples, with petroleum migrating from the GC645 reservoir to the oil seeps found in GC600 and up through the water column to the sea surface as an oil slick.

Here, we present atmospheric pressure photoionization (APPI) Fourier transform ion cyclotron resonance (FTICR) mass analysis of a volcanic asphalt sample by acquiring data for 20 Da wide mass segments across a 1000 Da range, stitched into a single composite mass spectrum, and compare to a broad-band mass spectrum for the same sample. The segmented spectrum contained 170 000 peaks with magnitude greater than 6σ of the root-mean-square (rms) baseline noise, for which 126 264 unique elemental compositions could be assigned. Approximately two-thirds of those compositions represent monoisotopic (i.e., chemically different) species. That complexity is higher than that for any previously reported mass spectrum and almost 3 times greater than that obtained from the corresponding broad-band spectrum (59 015). For the segmented mass spectrum, the signal-to-noise ratio (S/N) was significantly higher throughout the spectrum, but especially at the lower and upper ends of mass distribution relative to that of the near-Gaussian broad-band mass distribution. Despite this S/N improvement, mass measurement accuracy was noticeably improved only at lower masses. The increased S/N did, however, yield a higher number of peaks and higher dynamic range throughout the entire segmented spectrum relative to the conventional broad-band spectrum. The additional assigned peaks include higher heteroatom species, as well as additional radicals and isotopologues. Segmenting can require a significant investment in data acquisition and analysis time over broad-band spectroscopy (∼1775% in this case) making it best suited for targeted analysis and/or when complete compositional coverage is important. Finally, the present segmented spectrum contains, to our knowledge, more assigned peaks than any spectrum of any kind (e.g., UV-vis, infrared, microwave, magnetic resonance, etc.).

Corrosion control at refineries remains a challenge because the mechanism of naphthenic acid (NAP) corrosion is still not fully understood. The rate of NAP corrosion does not correlate with acidity (as measured by total acid number); therefore, it has been suggested that a subset of NAP in petroleum fractions may be more corrosive than others. Because the primary corrosion product (iron naphthenates) may thermally decompose to ketones at corrosion temperatures (250–400 °C), ketones in corrosion fluids could potentially be used to implicate specific problematic acids in corrosion tests. To that end, we have developed a method for isolating and characterizing ketones in corrosion test solutions. Ketones from tests on palmitic and 4-cyclohexyl pentanoic acids (C16H32O2 and C11H20O2) have been successfully isolated with a strong anion exchange solid-phase separation. Gas chromatography/mass spectrometry identifies ketones formed as a result of model acid corrosion. Fourier transform ion cyclotron resonance ma...

As levels of natural organic matter (NOM) in surface water rise, the minimization of potentially harmful disinfection by-products (DBPs) becomes increasingly critical. Here, we introduce the advantage that chromatographic prefractionation brings to investigating compositional changes to NOM caused by chlorination. Fractionation reduces complexity, making it easier to observe changes and attribute them to specific components. Under the conditions tested (0.1-0.4 g of Cl to g of C without further additives), the differences between highly and less oxidized NOM were striking. Highly oxidized NOM formed more diverse Cl-containing DPB, had a higher propensity to react with multiple Cl, and tended to transform so drastically as to no longer be amenable to electrospray-ionization mass spectral detection. Less-oxidized material tended to incorporate one Cl and retain its humiclike composition. N-containing, lipidlike, and condensed aromatic structure (CAS)-like NOM were selectively enriched in mass spectra, suggesting that such components do not react as extensively with NaOCl as their counterparts. Carbohydrate-like NOM, conversely, was selectively removed from spectra by chlorination.

Coal tar and its distilled products (e.g., creosote) are commonly applied wood preservatives and asphalt sealants that have been identified as significant sources of polycyclic aromatic hydrocarbons (PAHs) to the environment. Despite predictions that coal tar is composed of hundreds of compounds, few studies have ventured beyond measuring select PAHs with gas chromatography–mass spectrometry (GC-MS). Expanding the target analyte list will improve our capacity to gauge the inputs and impacts of organic compounds released from coal tar and its products into the environment. Employing a complementary approach with comprehensive two-dimensional gas chromatography (GC × GC) and Fourier transform ion cyclotron resonance mass spectrometry (FT-ICR MS), we analyzed residues suspected to be coal tar or creosote collected from beaches along coastal Texas in 2014. Over 3000 peaks were observed by GC × GC (compared to the 250 peaks found by our GC-MS analysis) in the whole extract of the samples. To remove PAHs and fo...