Powerful GC-TOF-MS Techniques for Screening, Identification and Quantification of Halogenated Natural Products

Abstract

Comprehensive two-dimensional gas chromatography/time-of-flight mass spectrometry (GC×GC TOFMS) and gas chromatography/high-resolution time-of-flight mass spectrometry (GC-HRT) were used to detect and identify halogenated natural products (HNPs) in tissue homogenate, in this case brominated analytes present in a marine snail. Two classes of brominated anthropogenic compounds, polybrominated diphenyl ethers (PBDEs) and brominated dibenzofurans, were analyzed for comparison. Following conventional preparation, the sample was analyzed using GC×GC-TOF-MS. Isotope ratio scripts were used to compile a list of putatively brominated analytes from amongst the thousands of features resolved in the twodimensional chromatogram. The structured nature of the chromatogram was exploited to propose identifications for several classes of brominated compounds, and include additional candidates that fell marginally outside the script tolerances. The sample was subsequently analyzed by GC-HRT. The high-resolution mass spectral data confirmed many formula assignments, facilitated confident assignment of an alternate formula when an original proposal did not hold, and enabled unknown identification. Identified HNPs include hydroxylated and methoxylated PBDE analogs, polybrominated dibenzo-p-dioxins (PBDDs) and hydroxyl-PBDDs, permitting the environmental occurrence and fate of such compounds to be studied.

Evaluation of gas chromatography – electron ionization – full scan high resolution Orbitrap mass spectrometry for pesticide residue analysis

“…A C C E P T E D ACCEPTED MANUSCRIPT 27 increasing from 15K to 30K, and further to 60K. A resolving power of 60K was shown to be required in certain cases and therefore used at all times.…”

“…However, thus far, hardly any applications have been described in the scientific literature [27,28].…”

Qualitative Analysis of Plant-Derived Samples by Liquid Chromatography-Electrospray Ionization-Quadrupole-Time of Flight-Mass Spectrometry

“…Therefore, it is urgent to devote more work to develop a solid mass database, similar to the NIST database for gas chromatography-MS [50]. It is also well known that TOF-MS can be used to identify an accurate molecular weight of target compounds in samples, and it appears that LC-Q-TOF-MS/MS could also be used to identify unknown compounds in samples [51,52]. However, it is currently difficult to identify structures of new target compounds using LC-Q-TOF-MS/MS alone, due to its complicated analysis methods and software.…”

Comparative mass spectrometry-based metabolomics strategies for the investigation of microbial secondary metabolites

“…67 The presence of heteroatoms, such as chlorine or bromine, are readily discernable in their contribution to the isotopic abundance observed for secondary metabolites and their stoichiometric contribution can be quickly verified through the use of isotopic calculator algorithms. 68 Furthermore, these approaches are equally well suited by the addition of non-natural isotopic enrichment or depletion for determining the relative or absolute abundance of the secondary metabolite that is expressed. One such approach termed stable isotope labeling in cell culture (SILAC) has been demonstrated as a facile tool for incorporating enrichment or depletion in experimental protocols.…”