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Search for Complex Nitrogen Heterocycles in Prebiotic Mixtures. Sample Information. Sample Prep. Samples arrived as dried extracts. 1 mL of MeOH (HPLC grade, JT Baker) was added to each sample vial, sonicated , and centrifuged. The extract was removed and placed into a new vial.
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Search for Complex Nitrogen Heterocycles in Prebiotic Mixtures
Sample Prep Samples arrived as dried extracts. 1 mL of MeOH (HPLC grade, JT Baker) was added to each sample vial, sonicated, and centrifuged. The extract was removed and placed into a new vial. Samples were prepared for analysis by negative mode electrospray ionization (ESI) by a 1:1 dilution with “spray juice”. Negative mode spray juice is a mixture of MeOH with 2% ammonium hydroxide solution (28% in water, Sigma-Aldrich, St. Louis, MO). Positive mode spray juice is a mixture of MeOH with 2% formic acid (Fluka Analytical).
Data Collection & Calibration Data collection was facilitated by a modular ICR data acquisition system (PREDATOR). Multiple (100) individual time-domain transients were co-added, Hanning-apodized, zero-filled, and fast Fourier transformed prior to frequency conversion to mass-to-charge ratio to obtain the final mass spectrum. Data was analyzed and peak lists were generated with custom-built software (MIDAS). Internal calibration of the spectrum was possible with the use of homologous series which repeat by 14.01565 Da (or CH2 units). IUPAC mass can be converted to Kendrick mass (Kendrick mass = IUPAC mass x (14/14.01565)) to sort compounds which differ by only 14 Da. Compounds with the same heteroatom content but differ by degree of alkylation can then be grouped together in a spreadsheet for more efficient analysis. Samples were calibrated on several NxOy species. Most abundant species were confirmed with 15N and 18O isotopes.
Data Visualization Data was visualized with graphs which show the relative abundances of the heteroatoms classes observed in each samples (classes greater than 1% in either sample shown) and through isoabundance color contour plots. In isoabundance color contour plots, all of the compounds in one heteroatom class are graphed with three dimensions. The x-axis, carbon number, gives the degree of alkylation. The y-axis, double bond equivalence (DBE or number of rings + double bonds to carbon), depicts aromaticity with the most aromatic compounds at the top of the graph. The third dimension is relative abundance represented by a color scale (see figures). Isoabundance color contour plots allow for the visualization of compositional space covered by each class.
Negative Mode ESI FT-ICR MS
Negative-Ion Electrospray Broadband 9.4 Tesla FT-ICR MS Sample 1 ~2600 Assigned Peaks Sample 2 ~3900 Assigned Peaks 200 300 400 500 600 700 800 m/z
Heteroatom Class Distribution of Acidic Species 5 4 3 % Relative Abundance 1 2 2 1 0 N1O6 N2O5 N2O6 N2O7 N2O8 N3O4 N3O5 N8O10 N9O9 N9O10 N3O6 N3O7 N3O8 N3O9 N4O5 N4O6 N4O7 N4O8 N4O9 N4O10 N5O5 N5O6 N5O7 N5O8 N5O9 N5O10 N6O6 N6O7 N6O8 N6O9 N6O10 N7O6 N7O7 N7O8 N7O9 N7O10 N8O8 N8O9 Heteroatom Class Negative ESI @ 9.4 Tesla
Relative Abundance (% total) 15 Sample 1 – N1O6 Sample 1 – N2O5 Sample 1 – N2O6 10 5 0 DBE 15 Sample 2 – N1O6 Sample 2 – N2O5 Sample 2 – N2O6 10 5 0 0 10 20 30 0 10 20 30 0 10 20 30 Carbon Number Neg ESI @ 9.4 Tesla
Relative Abundance (% total) 15 Sample 1 – N2O7 Sample 1 – N2O8 Sample 1 – N3O4 10 5 0 DBE 15 Sample 2 – N2O7 Sample 2 – N2O8 Sample 2 – N3O4 10 5 0 0 10 20 30 0 10 20 30 0 10 20 30 Carbon Number Neg ESI @ 9.4 Tesla
Relative Abundance (% total) 15 Sample 1 – N3O5 Sample 1 – N3O6 Sample 1 – N3O7 10 5 0 DBE 15 Sample 2 – N3O5 Sample 2 – N3O6 Sample 2 – N3O7 10 5 0 0 10 20 30 0 10 20 30 0 10 20 30 Carbon Number Neg ESI @ 9.4 Tesla
Relative Abundance (% total) 15 Sample 1 – N3O8 Sample 1 – N3O9 Sample 1 – N4O5 10 5 0 DBE 15 Sample 2 – N3O8 Sample 2 – N3O9 Sample 2 – N4O5 10 5 0 0 10 20 30 0 10 20 30 0 10 20 30 Carbon Number Neg ESI @ 9.4 Tesla
Relative Abundance (% total) 15 Sample 1 – N4O6 Sample 1 – N4O7 Sample 1 – N4O8 10 5 0 DBE 15 Sample 2 – N4O6 Sample 2 – N4O7 Sample 2 – N4O8 10 5 0 0 10 20 30 0 10 20 30 0 10 20 30 Carbon Number Neg ESI @ 9.4 Tesla
Relative Abundance (% total) 15 Sample 1 – N4O9 Sample 1 – N4O10 Sample 1 – N5O5 10 5 0 DBE 15 Sample 2 – N4O9 Sample 2 – N4O10 Sample 2 – N5O5 10 5 0 0 10 20 30 0 10 20 30 0 10 20 30 Carbon Number Neg ESI @ 9.4 Tesla
Relative Abundance (% total) 15 Sample 1 – N5O6 Sample 1 – N5O7 Sample 1 – N5O8 10 5 0 DBE 15 Sample 2 – N5O6 Sample 2 – N5O7 Sample 2 – N5O8 10 5 0 0 10 20 30 0 10 20 30 0 10 20 30 Carbon Number Neg ESI @ 9.4 Tesla
Relative Abundance (% total) 15 Sample 1 – N5O9 Sample 1 – N5O10 Sample 1 – N6O6 10 5 0 DBE 15 Sample 2 – N5O9 Sample 2 – N5O10 Sample 2 – N6O6 10 5 0 0 10 20 30 0 10 20 30 0 10 20 30 Carbon Number Neg ESI @ 9.4 Tesla
Relative Abundance (% total) 15 Sample 1 – N6O7 Sample 1 – N6O8 Sample 1 – N6O9 10 5 0 DBE 15 Sample 2 – N6O7 Sample 2 – N6O8 Sample 2 – N6O9 10 5 0 0 10 20 30 0 10 20 30 0 10 20 30 Carbon Number Neg ESI @ 9.4 Tesla
Relative Abundance (% total) 15 Sample 1 – N6O10 Sample 1 – N7O6 Sample 1 – N7O7 10 5 0 DBE 15 Sample 2 – N6O10 Sample 2 – N7O6 Sample 2 – N7O7 10 5 0 0 10 20 30 0 10 20 30 0 10 20 30 Carbon Number Neg ESI @ 9.4 Tesla
Relative Abundance (% total) 15 Sample 1 – N7O8 Sample 1 – N7O9 Sample 1 – N7O10 10 5 0 DBE 15 Sample 2 – N7O8 Sample 2 – N7O9 Sample 2 – N7O10 10 5 0 0 10 20 30 0 10 20 30 0 10 20 30 Carbon Number Neg ESI @ 9.4 Tesla
Relative Abundance (% total) 15 Sample 1 – N8O8 Sample 1 – N8O9 Sample 1 – N8O10 10 5 0 DBE 15 Sample 2 – N8O8 Sample 2 – N8O9 Sample 2 – N8O10 10 5 0 0 10 20 30 0 10 20 30 0 10 20 30 Carbon Number Neg ESI @ 9.4 Tesla
Relative Abundance (% total) 15 Sample 1 – N9O9 Sample 1 – N9O10 10 5 0 DBE 15 Sample 2 – N9O9 Sample 2 – N9O10 10 5 0 0 10 20 30 0 10 20 30 Carbon Number Neg ESI @ 9.4 Tesla
Positive Mode ESI FT-ICR MS
Positive-Ion Electrospray Broadband 9.4 Tesla FT-ICR MS x10 Sample 1 ~1200 Assigned Peaks x20 Sample 2 ~100 Assigned Peaks Data not visualized 200 300 400 500 600 700 800 m/z
Heteroatom Class Distribution of Basic Species 50 40 30 % Relative Abundance 1 20 10 0 N6O3 N6O4 N7O3 N7O4 N7O6 N8O2 N8O3 N8O4 N8O5 N8O6 N9O3 N9O4 N9O5 N9O6 N9O7 N10O5 N10O6 N10O7 N7O5 Heteroatom Class Positive ESI @ 9.4 Tesla
Relative Abundance (% total) 15 Sample 1 – N6O3 Sample 1 – N6O4 Sample 1 – N7O3 10 5 0 DBE 15 Sample 1 – N7O4 Sample 1 – N7O5 Sample 1 – N7O6 10 5 0 0 10 20 30 0 10 20 30 0 10 20 30 Carbon Number Pos ESI @ 9.4 Tesla
Relative Abundance (% total) 15 Sample 1 – N8O2 Sample 1 – N8O3 Sample 1 – N8O4 10 5 0 DBE 15 Sample 1 – N8O5 Sample 1 – N8O6 Sample 1 – N9O5 10 5 0 0 10 20 30 0 10 20 30 0 10 20 30 Carbon Number Pos ESI @ 9.4 Tesla
Relative Abundance (% total) 15 Sample 1 – N9O6 Sample 1 – N9O7 10 5 0 DBE 15 Sample 1 – N10O5 Sample 1 – N10O6 Sample 1 – N10O7 10 5 0 0 10 20 30 0 10 20 30 0 10 20 30 Carbon Number Pos ESI @ 9.4 Tesla