Consensus Structure Elucidation Combining GC/EI-MS, Structure Generation, and Calculated Properties

Abstract

This article explores consensus structure elucidation on the basis of GC/EI-MS, structure generation, and calculated properties for unknown compounds. Candidate structures were generated using the molecular formula and substructure information obtained from GC/EI-MS spectra. Calculated properties were then used to score candidates according to a consensus approach, rather than filtering or exclusion. Two mass spectral match calculations (MOLGEN-MS and MetFrag), retention behavior (Lee retention index/boiling point correlation, NIST Kovat's retention index), octanol−water partitioning behavior (log K ow ), and finally steric energy calculations were used to select candidates. A simple consensus scoring function was developed and tested on two unknown spectra detected in a mutagenic subfraction of a water sample from the Elbe River using GC/EI-MS. The top candidates proposed using the consensus scoring technique were purchased and confirmed analytically using GC/EI-MS and LC/MS/MS. Although the compounds identified were not responsible for the sample mutagenicity, the structure-generation-based identification for GC/EI-MS using calculated properties and consensus scoring was demonstrated to be applicable to real-world unknowns and suggests that the development of a similar strategy for multidimensional highresolution MS could improve the outcomes of environmental and metabolomics studies.

Non-target screening with high-resolution mass spectrometry: critical review using a collaborative trial on water analysis

“…Above 80 % (50 of 60, 81 of 96) of the target compounds that were in STOFF-IDENT were also within the calculated log D range using the RTI standards. While the majority of substances matched, the non-match of 10 and 15 manually validated target substances (per participant, respectively) shows that a consensus approach should be considered when using retention time prediction approaches [70].…”

Multicriteria Approach To Select Polyaromatic River Mutagen Candidates

“…As shown for GC-EI-MS the involvement of mass spectral substructure information and calculated properties may be effective in limiting the generated structures to a manageable number. 43 In this study, insufficient information from fragmentation patterns was available to limit the number of candidates sufficiently. This can be demonstrated for Peak 17 (SI Table S4), where the occurrence of only one fragment corresponding to a loss of carbonyl ([M+H-CO] + ) results in the generation of more than 10 000 000 possible structures for the formula C 20 H 9 N 3 O 2 .…”

Recent advances in the analysis of TBBPA/TBBPS, TBBPA/TBBPS derivatives and their transformation products

“…(B) Degradation of TBBPA derivatives predicted by UM-PPS. spectrometry characterization, and battery software applications should become the new trends for the identification of unknown metabolites or TBBPA/S and their derivatives in environmental matrices [59].…”