The science behind VeroMass
Rigorous, documented methodology you can trust. Three independent verification gates — mass, retention time, and spectral match — against a 40,000+ standard reference collection, delivering MSI Level 1a confidence.
Gate 1: Mass Accuracy
The measured mass of the precursor ion is compared against the theoretical monoisotopic mass of every standard in the library, across both ESI+ and ESI− adduct series. Tolerance window ≤ 9 mDa; typical observed error ±0.6 mDa. Adducts screened include [M+H]+, [M+Na]+, [M+NH4]+, [M−H]−, [M+FA−H]− and [M+Cl]−.
Flavonoids
Flavonols, flavones, flavanones, isoflavones, anthocyanins, biflavonoids — aglycones and O- and C-glycosides across all substitution patterns.
Phenolic Acids & Hydroxycinnamates
Caffeic, ferulic, sinapic, coumaric acids and their quinate, shikimate, and sugar esters, including chlorogenic acid isomers.
Alkaloids
Tropane, isoquinoline, indole, and pyrrolizidine alkaloids, each with characterised fragment pathways.
Terpenoids & Saponins
Mono-, sesqui-, di-, and triterpenoids, including saponins with complex sugar chains.
Lipids & Fatty Acids
Oxylipins, free fatty acids, glycerolipids, and phospholipids relevant to plant membrane biology.
Amino Acids & Derivatives
Proteinogenic and modified amino acids, betaines, and small-molecule nitrogen metabolites.
How the collection is built and kept:
- Mass range of 50–1500 Da
- Sourced from Sigma-Aldrich, Cayman, Cerilliant — ≥95% purity verified
- System suitability standards keep retention times reproducible within ±0.05 min
- Open metadata: InChIKey, SMILES, exact mass, measured RT, collision energy, lot number
- Library updated quarterly with new standards
Confirmed
Three orthogonal gates (mass, RT, MS²) agree against an authentic standard. Verified in both ESI+ and ESI−. This is what VeroMass delivers.
Putative
Matched to a library spectrum or diagnostic evidence, but no authentic standard is available for co-elution verification.
Tentative
Assigned to a compound class based on spectral similarity or predicted properties. A hypothesis, not an identification.
What Level 1a is not
In-silico tools that return ranked candidates based on predicted fragmentation do not reach Level 1a. However sophisticated the scoring, without a measured standard for RT and MS² validation, the answer is a probability, not an identity. VeroMass offers measured evidence, not ranked guesses.
Cosine Threshold
≥ 0.85 minimum cosine score between submitted and library MS² spectrum. The library-wide median cosine for true matches is 0.965, well above the threshold.
Mass Accuracy
Precursor mass tolerance of ≤ 9 mDa. The median observed error across all standards in both polarities is ±0.6 mDa, corresponding to sub-ppm accuracy on most small molecules.
Retention Time Tolerance
RT gate set at ≤ 0.3 min vs. the authentic standard. Co-elution is verified by the RT predictor (R² = 0.986) and cross-checked against the measured library RT.
Dual-Polarity Coverage
Every standard measured in both ESI+ and ESI−. Many metabolites ionise preferentially in one polarity; dual coverage ensures no compound is missed due to ionisation bias.
Collision Energy Variation
Each standard is fragmented at multiple collision energies (20, 35, 50 eV) to capture energy-dependent spectral variation and ensure robust matching across instrument types.
Batch Reproducibility
QC standards are reinjected every 20 samples to monitor mass drift, RT shift, and signal intensity. Acceptance criteria: mass error ≤ 3 mDa, RT shift ≤ 0.1 min over the entire batch.
The full methodology is documented above. If you are evaluating VeroMass and need additional detail for internal or peer review, contact us and we will provide it directly.