Estimates of Octanol-Water Partitioning for Thousands of Dissolved Organic Species in Oil Sands Process-Affected Water.

In this study, the octanol-water distribution ratios (DOW, that is, apparent KOW at pH 8.4) of 2114 organic species in oil sands process-affected water were estimated by partitioning to polydimethylsiloxane (PDMS) coated stir bars and analysis by ultrahigh resolution orbitrap mass spectrometry in electrospray positive ((+)) and negative ((-)) ionization modes. At equilibrium, the majority of species in OSPW showed negligible partitioning to PDMS (i.e., DOW <1), however estimated DOW's for some species ranged up to 100,000. Most organic acids detected in ESI- had negligible partitioning, although some naphthenic acids (O2(-) species) had estimated DOW ranging up to 100. Polar neutral and basic compounds detected in ESI+ generally partitioned to PDMS to a greater extent than organic acids. Among these species, DOW was greatest among 3 groups: up to 1000 for mono-oxygenated species (O(+) species), up to 127,000 for NO(+) species, and up to 203,000 for SO(+) species. A positive relationship was observed between DOW and carbon number, and a negative relationship was observed with the number of double bonds (or rings). The results highlight that nonacidic compounds in OSPW are generally more hydrophobic than naphthenic acids and that some may be highly bioaccumulative and contribute to toxicity.

Ozonation degrades all detectable organic compound classes in oil sands process-affected water; an application of high-performance liquid chromatography/obitrap mass spectrometry.

RATIONALE: Surface mining of bitumen in Northern Alberta, Canada, results in large volumes of toxic oil sands process-affected water (OSPW) that must be contained in tailings ponds. Ozonation has shown great promise as an OSPW treatment process, by decreasing its toxicity and increasing its biodegradability, but the effect of ozonation on the thousands of dissolved organic chemical groups has not yet been examined. METHODS: Reversed-phase liquid chromatography with ultrahigh-resolution linear ion trap-orbitrap mass spectrometry was applied to the characterization of treated (utilized ozone doses of 20 and 50 mg O3/L) and untreated OSPW. The analysis was performed in positive and negative electrospray ionization modes for each sample (ESI(+)/ESI(-)). RESULTS: Semi-quantitative analysis of ozonated and unozonated samples allowed degradation to be monitored for naphthenic acids (i.e. O2 species in ESI(-) mode) and >2000 other organic species belonging to various heteroatom-containing classes: Ox (where x = 1 to 6), NOx (where x = 1 to 4), SOx (where x = 1 to 4), NO2 S, N, and S. No chlorinated byproducts were detected in any treated sample, but at the low dose (20 mg O3/L) some compound classes increased in abundance (e.g. the O5 class), indicating that they were formed as byproducts at faster rates than they were degraded. Nevertheless, all organic compound classes subsequently diminished at the higher dose (50 mg O3/L). For several Ox and SOx classes, species observed in ESI(+) mode (e.g. O2(+) species) were often more recalcitrant to ozonation than the corresponding species detected in ESI(-) mode (e.g. O2(-) species; naphthenic acids). CONCLUSIONS: Ozonation appears to be a very suitable treatment option for OSPW, but the more recalcitrant groups of compounds may help to explain the residual toxicity of ozonated OSPW. Analysis of OSPW constituents in both ionization modes is warranted in all future OSPW fate studies.

Characterization of oil sands process-affected waters by liquid chromatography orbitrap mass spectrometry.

Recovery of bitumen from oil sands in northern Alberta, Canada, occurs by surface mining or in situ thermal recovery, and both methods produce toxic oil sands process-affected water (OSPW). A new characterization strategy for surface mining OSPW (sm-OSPW) and in situ OSPW (is-OSPW) was achieved by combining liquid chromatography with orbitrap mass spectrometry (MS). In electrospray positive and negative ionization modes (ESI(+)/ESI(-)), mass spectral data were acquired with high resolving power (RP > 100,000-190,000) and mass accuracy (<2 ppm). The additional chromatographic resolution allowed for separation of various isomers and interference-free MS(n) experiments. Overall, ∼3000 elemental compositions were revealed in each OSPW sample, corresponding to a range of heteroatom-containing homologue classes: Ox (where x = 1-6), NOx (where x = 1-4), SOx (where x = 1-4), NO2S, N, and S. Despite similarities between the OSPW samples at the level of heteroatom class, the two samples were very different when considering isomer patterns and double-bond equivalent profiles. The chromatographic separations also allowed for confirmation that, in both OSPW samples, the O2 species detected in ESI(-) (i.e., naphthenic acids) were chemically distinct from the corresponding O2 species detected in ESI(+). In comparison to model compounds, tandem MS spectra of these new O2 species suggested a group of non-acidic compounds with dihydroxy, diketo, or ketohydroxy functionality. In light of the known endocrine-disrupting potential of sm-OSPW, the toxicity of these O2 species deserves attention and the method should be further applied to environmental forensic analysis of water in the region.

Evaluation of electron capture detection in reversed-phase HPLC for pharmaceutical analysis.

The coupling of RP-LC to electron capture detection (ECDNi(63)) is described. To reduce the amount of mobile phase entering into the detector, interfacing was performed via a Scott-type spray chamber. The performance of RP-LC/ECDNi(63) was evaluated for pharmaceutical analysis and the results show that the system is able to work in a routine environment using columns with 2 mm id and common amounts of the organic modifiers methanol or ACN in the mobile phase. Because of the high sensitivity and selectivity toward electrophilic compounds, the use of this detector opens possibilities for the analysis of impurities down to the 0.05% level of active pharmaceutical ingredients (API).

Design and evaluation of a multi-detection system composed of ultraviolet, evaporative light scattering and inductively coupled plasma mass spectrometry detection for the analysis of pharmaceuticals by liquid chromatography.

Reversed-phase liquid chromatography was coupled to a multi-detection system composed of ultraviolet (UV) detection, evaporative laser scattering detection (ELSD) and inductively coupled plasma mass spectrometry (ICP-MS). By applying the principle of post-column solvent compensation, the organic modifier content was kept constant in ELSD and ICP-MS under gradient elution. Chlorine ((35)Cl), bromine ((79)Br and (81)Br) and sulfur ((34)S) were monitored in several pharmaceutical compounds. The limit of quantitation (LOQ) was 80 ng/mL for chlorine (chlorpropamide) and 2 ng/mL for bromine (bromazepam). Calibration graphs were linear from 1.0 microg/mL to 100 microg/mL for chlorpropamide (r(2) 0.990) and from 10 ng/mL to 500 ng/mL for bromazepam (r(2) 0.996). The low LOQ value for bromine allows to quantify bromine in pharmaceutical samples below the 0.05% level of the active pharmaceutical ingredient.

Serial coupling of reversed-phase and hydrophilic interaction liquid chromatography to broaden the elution window for the analysis of pharmaceutical compounds.

It is presently a common practice in drug discovery to analyse samples by reversed-phase liquid chromatography (RPLC) and hydrophilic interaction chromatography (HILIC). To increase throughput, HILIC was connected in series to RPLC by means of a T-piece with make-up flow. The first column is a 2mm I.D. column having an optimal flow between 0.1 and 0.2mL/min. Via the T-piece, the flow for the second dimension column with an I.D. of 4.6mm is adjusted to 1.5-2.0mL/min with a high acetonitrile content (i.e. >/=80%) mobile phase. Therefore, even in gradient RPLC analysis starting with a mobile phase with high water content, the HILIC column is always operated at high acetonitrile concentration which is required to obtain retention on the HILIC column. The performance of the hyphenated RPLC/HILIC set-up is illustrated with the analysis of two model samples of pharmaceutical interest. Optimization of the conditions in the HILIC dimension is discussed.

Analysis of dihydropyridine calcium channel blockers using negative ion photoionization mass spectrometry.

The fragmentation of dihydropyridine calcium-channel antagonists are compared by electrospray ionization (ESI) and atmospheric pressure photonization (APPI). The results demonstrate that in ESI the preferred ionization process is in positive mode, with the mass spectra of [M+H]+ showing base peak ions probably formed by loss of alcohols from carboxyl groups. Conversely, in APPI, a high intense peak is observed in negative mode due to deprotonated molecule [M-H]- after two serial 1, 2-hydride shifts leading to a rearranged deprotonated molecule [M-H]-. These ions undergo another 1,2-hydride shifts to produce a nitro-phenyl product ion of m/z 122. The APPI is also used to develop a method for the quantitation of dihydropyridines (e.g., nifedipine) in human plasma.

Inhibition of ABC transport proteins by oil sands process affected water.

The ATP-binding cassette (ABC) superfamily of transporter proteins is important for detoxification of xenobiotics. For example, ABC transporters from the multidrug-resistance protein (MRP) subfamily are important for excretion of polycyclic aromatic hydrocarbons (PAHs) and their metabolites. Effects of chemicals in the water soluble organic fraction of relatively fresh oil sands process affected water (OSPW) from Base Mine Lake (BML-OSPW) and aged OSPW from Pond 9 (P9-OSPW) on the activity of MRP transporters were investigated in vivo by use of Japanese medaka at the fry stage of development. Activities of MRPs were monitored by use of the lipophilic dye calcein, which is transported from cells by ABC proteins, including MRPs. To begin to identify chemicals that might inhibit activity of MRPs, BML-OSPW and P9-OSPW were fractionated into acidic, basic, and neutral fractions by use of mixed-mode sorbents. Chemical compositions of fractions were determined by use of ultrahigh resolution orbitrap mass spectrometry in ESI(+) and ESI(-) mode. Greater amounts of calcein were retained in fry exposed to BML-OSPW at concentration equivalents greater than 1× (i.e., full strength). The neutral and basic fractions of BML-OSPW, but not the acidic fraction, caused greater retention of calcein. Exposure to P9-OSPW did not affect the amount of calcein in fry. Neutral and basic fractions of BML-OSPW contained relatively greater amounts of several oxygen-, sulfur, and nitrogen-containing chemical species that might inhibit MRPs, such as O(+), SO(+), and NO(+) chemical species, although secondary fractionation will be required to conclusively identify the most potent inhibitors. Naphthenic acids (O2(-)), which were dominant in the acidic fraction, did not appear to be the cause of the inhibition. This is the first study to demonstrate that chemicals in the water soluble organic fraction of OSPW inhibit activity of this important class of proteins. However, aging of OSPW attenuates this effect and inhibition of the activity of MRPs by OSPW from Base Mine Lake does not occur at environmentally relevantconcentrations.

Pharmacokinetics of dihydroergocristine and its major metabolite 8'-hydroxy-dihydroergocristine in human plasma.

Dihydroergocristine (DHEC) is a semi-synthetic drug mainly used for age-related cognitive impairment. In this study, its major metabolite 8'-hydroxy-dihydroergocristine (8'-OH-DHEC) was produced in incubates of a bovine liver preparation using dihydroergocristine mesylate (DHECM) as substrate. Purification was achieved by flash silica gel column and reverse phase liquid chromatographies, and identification was based on accurate molecular mass measurements, mass fragmentation spectra and NMR ((1)H/(13)C) chemical shifts. By using the substance produced in vitro, a fast, sensitive, specific and robust LC/MS/MS method for the simultaneous determination of DHEC and its major metabolite in human plasma was developed and validated. Bromocriptine was used as internal standard and limits of quantification for DHEC and 8'-OH-DHEC were 10 pg/ml and 20 pg/ml, respectively. Pharmacokinetic parameters were investigated on 12 male healthy volunteers to whom a single dose of 18 mg DHECM was administered in tablets (Iskevert). The peak of DHEC was 0.28 +/- 0.22 microg/l, the t(max) 0.46 +/- 0.26 h, the AUC(last) 0.39 +/- 0.41 microg/l.h and the terminal elimination half-life 3.50 +/- 2.27 h. The peak of 8'-OH-DHEC was 5.63 +/- 3.34 microg/l, the t(max) 1.04 +/- 0.66 h, the AUC(last) 13.36 +/- 5.82 microg/l.h and the terminal elimination half-life 3.90 +/- 1.07 h. Dosing of 18 mg DHECM was well tolerated, causing no adverse events.

Quantification of the bombesin/gastrin releasing peptide antagonist RC-3095 by liquid chromatography-tandem mass spectrometry.

Bombesin (BN) and its mammalian equivalent, gastrin-releasing peptide (GRP), stimulate cell proliferation and are involved in the pathogenesis of several types of human cancer. BN/GRP and their receptors were shown to be critical for the growth of various human malignancies, such as small-cell lung, prostate, ovary, stomach and breast cancers in the human tumor xenograft model. In the present study, a fast, sensitive, robust method was developed for the determination and quantification of a BN/GRP receptor antagonist RC-3095 (D-Tpi-Gln-Trp-Ala-Val-Gly-His-Leupsi(CH2NH)Leu-NH2), in human plasma by liquid chromatography coupled with tandem mass spectrometry. RC-3095 was extracted from 0.2 ml human plasma by protein precipitation using cold acetonitrile (0.4 ml). The method has a chromatographic run of 10 min using a C(8) analytical column (150 mm x 4.6 mm i.d.) and the linear calibration curve over the range was linear from 20 to 10000 ng ml(-1) (r(2)>0.994). The between-run precision, based on the relative standard deviation replicate quality controls, was 5.7% (60 ng ml(-1)), 7.1% (600 ng ml(-1)) and 6.8% (8000 ng ml(-1)). The between-run accuracy was +/-0.0, 2.1 and 3.1% for the above-mentioned concentrations, respectively. The developed procedure allows the quantitative determination of peptide RC-3095 for pharmacokinetics studies in human plasma.

Felodipine quantification in human plasma by high-performance liquid chromatography coupled to tandem mass spectrometry.

A rapid, sensitive, robust and specific method was developed for the determination and quantitation of felodipine, in human blood plasma by liquid chromatography coupled with tandem mass spectrometry using nimodipine as internal standard. Felodipine was extracted from 0.5 mL human plasma by use of a liquid/liquid procedure using diethyl ether/hexane (80/20, v/v) as eluent. The method included a chromatographic run of 5 min using a C(18) analytical column (100 mm x 4.6 mm i.d.) and the calibration curve was linear over the range from 0.02 to 10 ng mL(-1) (r(2) > 0.994). The between-run precision, determined as relative standard deviation of replicate quality controls, was 5.7% (0.06 ng mL(-1)), 7.1% (0.6 ng mL(-1)) and 6.8% (7.5 ng mL(-1)). The between-run accuracy was +/- 0.0, 2.1 and 3.1% for the above-mentioned concentrations, respectively.

Atmospheric pressure photoionization applied to quantitation of cyproterone acetate in human plasma.

Cyproterone acetate [6-chloro-1beta,2beta-dihydro-17alpha-hydroxy- 3'H-cyclopropa(1,2)-pregna-1,4,6-triene-3,20-dione acetate] is a powerful antiandrogen used in the treatment of women suffering from disorders associated with androgenization such as hirsutism and acne. A fast, sensitive, and robustness method is developed for the determination and quantitation of cyproterone acetate in human blood plasma by liquid chromatography coupled with tandem mass spectrometry. Cyproterone acetate is extracted from 0.2 mL human plasma by liquid-liquid extraction. The method has a chromatographic run of 4.5 min, using a C18 analytical column (100- yen 2.1-mm i.d.), and the linear calibration curve over the range is linear from 1 to 500 ng/mL (r2 > 0.994). The between-run precision, based on the relative standard deviation replicate quality controls, is 96.2% (3 ng/mL), 97.5% (120 ng/mL), and 99.1% (400 ng/mL). The between-run accuracy was +/- 2.7%, 3.1%, and 4.8% for the previously mentioned concentrations, respectively. The method is employed in a bioequivalence study of two tablet formulations of cyproterone acetate (100 mg).

Temporal trends of perfluorooctanesulfonate isomer and enantiomer patterns in archived Swedish and American serum samples.

Human perfluorooctanesulfonate (PFOS) body burdens are attributable to both direct PFOS and indirect PFOS precursor (PreFOS) exposure. The relative importance of these two pathways has been estimated, but the relative temporal trajectory of exposure to PFOS and PreFOS has not been examined. Here, two hypothesized biomarkers of PreFOS exposure, PFOS isomer profiles (quantified as percent branched PFOS, %br-PFOS) and chiral 1m-PFOS enantiomer fractions (1m-PFOS EF) were analyzed in archived human serum samples of individual American adults (1974-2010) and pooled samples of Swedish primiparous women (1996-2010). After correcting for potential confounders, significant correlations between %br-PFOS and 1m-PFOS EFs were observed in American samples and in Swedish samples for the 1996-2000 period, supporting the hypothesis that both %br-PFOS and 1m-PFOS EF are biomarkers of PreFOS exposure. Significant trends of increasing %br-PFOS, from 2000 to 2010, and increasingly non-racemic 1m-PFOS EFs, from 1996 to 2000, were detected in Swedish samples. No statistically significant trend for %br-PFOS or 1m-PFOS EF was observed in American samples, but American males had significantly higher %br-PFOS and significantly lower 1m-PFOS EF (i.e. more non-racemic) than females, and a similar significant difference was shown in the older age group, relative to the younger age group. These temporal trends in %br-PFOS and 1m-PFOS EF are not easily explained and the results highlight uncertainties about how humans are exposed to PFOS.

Three series of high molecular weight alkanoates found in Amazonian plants.

Electron impact mass spectra were measured by high temperature high resolution gas chromatography-mass spectrometry (HT-HRGC-MS) for three homologous series of high molecular weight compounds present in the Amazonian plants Marupá (Simaruba amara) and Brazil nut (Bertholettia excelsa). Based on their mass spectra, the compounds were identified as three wax ester series of alpha-tocopherol (vitamin E), beta-tocopherol and phytol (2,6,10,14-tetramethylhexadec-14-en-16-ol). The interpretations are supported by high resolution mass spectrometry and GC retention indices of authentic standards.

Flavonoids and trypanocidal activity of Bulgarian propolis.

Acetone and ethanol extracts of two Bulgarian propolis samples (Bur and Lov) were investigated by high temperature high resolution gas chromatography coupled to mass spectrometry (HT-HRGC-MS), and their activity against Trypanosoma cruzi was evaluated. The ethanol extracts--Et-Bur and Et-Lov--showed similar composition, with a high content of flavonoids, and strong inhibitory activity against T. cruzi proliferative epimastigotes, which were more susceptible than trypomastigotes. In the presence of blood, the activity of Et-Bur or Et-Lov against trypomastigotes was similar to that of the standard drug, crystal violet. Both extracts also showed similar and significant activity against Staphylococcus aureus and Candida albicans, while being inactive against Escherichia coli. The acetone extract, Ket-Bur, was more active than Et-Bur against both forms of T. cruzi.

Lupeol alkanoates in Brazilian propolis.

High temperature high resolution gas chromatography coupled to mass spectrometry (HT-HRGC-MS) isa powerful analytical tool. In this work we applied this technique to the study of crude extracts of propolis collected near the city of Uberlândia-Minas Gerais State. Eucalyptus trees and native plants from "cerrado" (savannah) were the material sources disposable for the Apis mellifera bees. A lot of known propolis constituents were identified, however, several high molecular weight compounds including lupeol alkanoates were identified for first time in propolis.