Screening and identification of unknown contaminants in water with liquid chromatography and quadrupole-orthogonal acceleration-time-of-flight tandem mass spectrometry

Bobeldijk, I.; Vissers, J.P.C.; Kearney, Gordon C.; Major, Hilary; Leerdam, J.A. van

doi:10.1016/s0021-9673(01)01156-6

Cited by 130 publications

(69 citation statements)

References 12 publications

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“…The accurate mass measurements can then be used to derive possible elemental compositions of these ions with the aid of computer software and known structural features of the molecule. Thus, accurate mass measurements frequently are invaluable in arriving at less ambiguous mass-spectral and structural assignments (Pilard et al, 2000;Zhang et al, 2000;Bobeldijk et al, 2001;Watt et al, 2001;Lopes et al, 2002). In our studies, the measurement of accurate masses of the molecular ions of the parent compounds and metabolites were useful at unambiguously establishing that the 2,2-DMPy metabolites had lost a mass equivalent to a ϪC 3 H 6 moiety relative to the corresponding 2,2,6,6-TMPi analogs.…”

Section: Discussionmentioning

confidence: 84%

A Novel P450-Catalyzed Transformation of the 2,2,6,6-Tetramethyl Piperidine Moiety to a 2,2-Dimethyl Pyrrolidine in Human Liver Microsomes: Characterization by High Resolution Quadrupole-Time-of-Flight Mass Spectrometry and ¹H-NMR

Yin

Doss²,

Stearns³

et al. 2003

Drug Metab Dispos

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ABSTRACT:We describe herein a novel metabolic fate of the 2,2,6,6-tetramethyl-piperidine (2,2,6,6-TMPi) moiety to a ring-contracted 2,2-dimethyl pyrrolidine (2,2-DMPy) in human liver microsomal incubations. The existence of this pathway was demonstrated for three compounds (I-III) of varied structures suggesting that this may be a general biotransformation reaction for the 2,2,6,6-TMPi moiety. The 2,2-DMPy metabolites formed in incubations of the three compounds with human liver microsomes were characterized by online high performance liquid chromatography coupled to a high resolution hybrid quadrupole-time-of-flight mass spectrometer. Suggested elemental composition obtained from accurate mass measurements of the molecular ions and fragment ions of the metabolites clearly indicated the loss of a mass equivalent to C 3 H 6 from the parent 2,2,6,6-TMPi functionality. Additional accurate tandem mass spectrometry data indicated that one of the original two gem-dimethyl groups was intact in the metabolite structure. Proof of a ring-contracted 2,2-DMPy structure was obtained using 1 H-NMR experiments on a metabolite purified from liver microsomal incubations, which showed only two geminal methyl groups, instead of four in the parent compound. Two-dimensional correlation spectroscopy and decoupling experiments established aliphatic protons arranged in a pyrrolidine ring pattern. The fact that the formation of 2,2-DMPy metabolites in human liver microsomes was NADPH-dependent suggested that this novel metabolic reaction was catalyzed by the cytochrome P450 (P450) enzyme(s). Immunoinhibition studies in human liver microsomal incubations using anti-P450 monoclonal antibodies and experiments with insect cell microsomes containing individually expressed recombinant human P450 isozymes indicated that multiple P450 isozymes were capable of catalyzing this novel metabolic transformation.

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Section: Discussionmentioning

confidence: 84%

A Novel P450-Catalyzed Transformation of the 2,2,6,6-Tetramethyl Piperidine Moiety to a 2,2-Dimethyl Pyrrolidine in Human Liver Microsomes: Characterization by High Resolution Quadrupole-Time-of-Flight Mass Spectrometry and ¹H-NMR

Yin

Doss²,

Stearns³

et al. 2003

Drug Metab Dispos

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“…A triple quadrupole analyzer is the most commonly used analyzer for target analysis, although some studies use different analyzers such as ion-trap [12,17], quadrupole-time of flight (QTOF) [18,19], or quadrupole-ion trap (QTrap) [20].…”

Section: Introductionmentioning

confidence: 99%

Occurrence of pharmaceuticals and hormones in sewage sludge

Nieto

Borrull

Pocurull

et al. 2010

Enviro Toxic and Chemistry

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The present study evaluates the presence of nine hormones and their conjugates and 20 pharmaceuticals such as anti-inflammatories, lipid regulators, and antibiotics among others in sewage sludge from two sewage treatment plants (STPs) in the Tarragona area (Spain) for the period March 2007 until March 2008. Target analytes have been determined using different methods involving pressurized liquid extraction and liquid chromatography (electrospray ionization) tandem mass spectrometry (MS-MS). Most of the pharmaceuticals and hormones were found at low micrograms per kilogram dry weight levels in the sewage sludge samples analyzed. Some compounds were present in all samples, such as acetaminophen, caffeine, carbamazepine, and ibuprofen, among others. Other compounds, such as estriol, were found only in the STP of Reus. The compounds that showed the highest concentration in both STPs were roxithromycin and tylosin (1,446 and 1,958 microg/kg dry wt, respectively). The presence of these compounds in sewage sludge demonstrated that they are partially or totally removed from the influent wastewater by sorption into the sewage sludge.

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“…Typical applications are metabolite identification, verification of positive findings, and screening for unknowns. Q-TOF-MS is much more useful than TOF-MS in environmental application, because product ion spectra can be detected with high mass resolution, which is essential for the identification of unknowns [210]. In this way, not only can the elemental formula of a molecular ion be determined, but unambiguous information on some of its structural characteristics can be obtained.…”

Section: Time-of-flight Msmentioning

confidence: 99%

“…Because of its high resolution and good sensitivity over a full mass range, TOF-MS would seem to be advantageous for screening purposes. The use of a Q-TOF can be even more useful, as it enables product ion spectra to be recorded for further identification [210]. The high mass resolution provided by a TOF-MS can be used to reduce the chemical noise in selected ion chromatograms [212].…”

Section: Time-of-flight Msmentioning

confidence: 99%

Analytical Methods for Polar Pollutants

Reemtsma

Quintana

2006

Organic Pollutants in the Water Cycle

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Screening and identification of unknown contaminants in water with liquid chromatography and quadrupole-orthogonal acceleration-time-of-flight tandem mass spectrometry

Cited by 130 publications

References 12 publications

A Novel P450-Catalyzed Transformation of the 2,2,6,6-Tetramethyl Piperidine Moiety to a 2,2-Dimethyl Pyrrolidine in Human Liver Microsomes: Characterization by High Resolution Quadrupole-Time-of-Flight Mass Spectrometry and ¹H-NMR

A Novel P450-Catalyzed Transformation of the 2,2,6,6-Tetramethyl Piperidine Moiety to a 2,2-Dimethyl Pyrrolidine in Human Liver Microsomes: Characterization by High Resolution Quadrupole-Time-of-Flight Mass Spectrometry and ¹H-NMR

Occurrence of pharmaceuticals and hormones in sewage sludge

Analytical Methods for Polar Pollutants

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Screening and identification of unknown contaminants in water with liquid chromatography and quadrupole-orthogonal acceleration-time-of-flight tandem mass spectrometry

Cited by 130 publications

References 12 publications

A Novel P450-Catalyzed Transformation of the 2,2,6,6-Tetramethyl Piperidine Moiety to a 2,2-Dimethyl Pyrrolidine in Human Liver Microsomes: Characterization by High Resolution Quadrupole-Time-of-Flight Mass Spectrometry and 1H-NMR

A Novel P450-Catalyzed Transformation of the 2,2,6,6-Tetramethyl Piperidine Moiety to a 2,2-Dimethyl Pyrrolidine in Human Liver Microsomes: Characterization by High Resolution Quadrupole-Time-of-Flight Mass Spectrometry and 1H-NMR

Occurrence of pharmaceuticals and hormones in sewage sludge

Analytical Methods for Polar Pollutants

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Product

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About

A Novel P450-Catalyzed Transformation of the 2,2,6,6-Tetramethyl Piperidine Moiety to a 2,2-Dimethyl Pyrrolidine in Human Liver Microsomes: Characterization by High Resolution Quadrupole-Time-of-Flight Mass Spectrometry and ¹H-NMR

A Novel P450-Catalyzed Transformation of the 2,2,6,6-Tetramethyl Piperidine Moiety to a 2,2-Dimethyl Pyrrolidine in Human Liver Microsomes: Characterization by High Resolution Quadrupole-Time-of-Flight Mass Spectrometry and ¹H-NMR