Automatic Assignment of Molecular Ion Species to Elemental Formulas in Gas Chromatography/Methane Chemical Ionization Accurate Mass Spectrometry
Abstract
:1. Introduction
2. Materials and Method
2.1. Data Acquisition
2.2. Data Analysis and Molecular Assignment Algorithms
3. Results
3.1. CI Pattern of Molecular Ion Species
3.2. Overall Detection Rate of Molecular Ion Species in GC-CI-QTOF MS
3.3. Automatic Calculation of Elemental Formulas
4. Conclusions
Supplementary Materials
Author Contributions
Funding
Institutional Review Board Statement
Informed Consent Statement
Data Availability Statement
Acknowledgments
Conflicts of Interest
References
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Gas Chromatograph | Agilent 7890A GC System |
---|---|
Mass Spectrometer | 7200 accurate mass QTOF mass spectrometer |
GC column | DB5 MS column 30 m + 10 m integrated guard, 0.25 mm id, 0.25 μm film |
GC parameters, injection | 1 μL in 25 s splitless mode at 250 °C |
GC parameters, separation | Initial temperature of 60 °C with a hold time of 0.5 min, a temperature ramp of 10 °C/min to 325 °C, and a final hold time of 10 min at 325 °C. |
EI ion source | temperature, 230 °C; energy, 70 eV |
Chemical ionization | Ion source 300 °C; CI electron energy 135 eV; CI methane gas flow rate 20% |
MS parameters, tuning | Autotune using FC43 (Perfluoro tributylamine) |
MS parameters, data acquisition | m/z 50–1200 at 5 Hz scan rate and 750 V detector voltage in both electron ionization (EI) mode and chemical ionization (CI) mode |
MS data processing | Peak detection, deconvolution by MS-DIAL 4 [13,16] |
Class | # | Detected by CI (%) |
---|---|---|
Carboxylic acids and deriv. | 77 | 83.1 |
Organooxygen compounds | 47 | 55.3 |
Benzene and substituted deriv. | 35 | 77.1 |
Fatty acyls | 29 | 89.7 |
Phenols | 26 | 73.1 |
Indoles and deriv. | 15 | 86.7 |
Organonitrogen compounds | 11 | 63.6 |
Hydroxy acids and deriv. | 9 | 88.9 |
Phenylpropanoic acids | 8 | 87.5 |
Prenol lipids | 8 | 25.0 |
Cinnamic acids and deriv. | 7 | 71.4 |
Pyridines and derivatives | 7 | 100.0 |
Steroids and steroid deriv. | 7 | 14.3 |
Purine nucleosides | 6 | 100.0 |
[M]+ | 15 | 4% |
[M − H]+ | 24 | 7% |
[M + H]+ | 255 | 74% |
Not recognized by algorithm | 51 | 15% |
Total | 345 | Derivatized standards |
Observed m/z | Theoretical | Mass Error [mDa] | Ion Species | |
---|---|---|---|---|
3,4-dihydroxy-phenylacetic acid | 384.1612 | 384.1608 | −0.4 | [M]+ 3TMS |
369.1377 | 369.1374 | −0.3 | [M − CH3]+ 3TMS | |
413.2004 | 413.2000 | −0.4 | [M + C2H5]+ 3TMS | |
425.1996 | 425.2000 | 0.4 | [M + C3H5]+ 3TMS | |
457.2088 | 457.2082 | −0.6 | [M + TMS]+ 3TMS | |
phosphoric acid | 315.1031 | 315.1033 | 0.2 | [M + H]+ 3TMS |
299.0719 | 299.0720 | 0.1 | [M − CH3]+ 3TMS | |
343.1345 | 343.1346 | 0.1 | [M + C2H5]+ 3TMS | |
355.1342 | 355.1346 | 0.4 | [M + C3H5]+ 3TMS | |
387.1428 | 387.1428 | 0.0 | [M + TMS]+ 3TMS | |
2,5-dihydroxy-phenylacetic acid | 384.1608 | 384.1608 | 0.0 | [M]+ 3TMS |
369.1374 | 369.1374 | 0.0 | [M − CH3]+ 3TMS | |
413.1995 | 413.2000 | 0.5 | [M + C2H5]+ 3TMS | |
425.1985 | 425.2000 | 1.5 | [M + C3H5]+ 3TMS | |
457.2082 | 457.2082 | 0.0 | [M + TMS]+ 3TMS |
Correct Formula | Molecular Ion Species | [M − CH3]+ | W/Isotope Pattern |
---|---|---|---|
No hit | 7.9% | 6.9% | 12.8% |
Top-10 | 91.7% | 93.1% | 87.2% |
Top-5 | 87.6% | 91.0% | 83.4% |
Top-3 | 83.1% | 86.9% | 78.6% |
Top hit | 60.7% | 71.4% | 59.0% |
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Wang, S.; Valdiviez, L.; Ye, H.; Fiehn, O. Automatic Assignment of Molecular Ion Species to Elemental Formulas in Gas Chromatography/Methane Chemical Ionization Accurate Mass Spectrometry. Metabolites 2023, 13, 962. https://doi.org/10.3390/metabo13080962
Wang S, Valdiviez L, Ye H, Fiehn O. Automatic Assignment of Molecular Ion Species to Elemental Formulas in Gas Chromatography/Methane Chemical Ionization Accurate Mass Spectrometry. Metabolites. 2023; 13(8):962. https://doi.org/10.3390/metabo13080962
Chicago/Turabian StyleWang, Shunyang, Luis Valdiviez, Honglian Ye, and Oliver Fiehn. 2023. "Automatic Assignment of Molecular Ion Species to Elemental Formulas in Gas Chromatography/Methane Chemical Ionization Accurate Mass Spectrometry" Metabolites 13, no. 8: 962. https://doi.org/10.3390/metabo13080962
APA StyleWang, S., Valdiviez, L., Ye, H., & Fiehn, O. (2023). Automatic Assignment of Molecular Ion Species to Elemental Formulas in Gas Chromatography/Methane Chemical Ionization Accurate Mass Spectrometry. Metabolites, 13(8), 962. https://doi.org/10.3390/metabo13080962