Plasma Dataset of oldman 500

The dataset was obtained as part of a non-targeted blood plasma metabolome study using two-dimensional gas chromatography coupled with time-of-flight mass spectrometry (GC×GC–TOF-MS). The experiment included 500 biological samples, each of which was analysed in three technical replicates.

Metabolite extraction was performed by adding 1 ml of extraction solvent (methanol:water, 8:2, v:v) to 30 μl of plasma, followed by vigorous shaking. The samples were centrifuged for 2 minutes at 20,000 rpm, after which 950 µl of supernatant was collected, completely dried in a SpeedVac concentrator, and sent for methoxymation and derivatisation according to the published protocol (DOI: 10.1002/0471142727.mb3004s114). A mixture of fatty acid methyl esters (FAME) was used as internal standards. After methoxylation, 91 µl of a FAME/MSTFA mixture prepared by adding 1 µl of MSTFA to 10 µl of FAME solution was added to each sample.

Metabolomic profiling was performed using the LECO Pegasus BT-4D system, which includes an Agilent 7890B two-dimensional gas chromatograph, a time-of-flight mass spectrometer, and an L-PAL3 autosampler. Two-dimensional chromatography was performed on Rxi-5MS (29.7 m × 250 μm) and Rxi-17Sil MS (1.96 m × 250 μm) columns manufactured by Restek. The instrument was controlled and data were collected using ChromaTOF software (v.5.51.06.0.64572). Before starting the measurements, calibration was performed using PFTBA (FC43) and the system was checked for leaks. Sample injection (1 μl) was performed at an injector temperature of 250 °C in a 1:50 split mode (He 99.9999%). The initial oven temperature was 60 °C (1 min), followed by a gradient of 10 °C/min for 12 minutes. The GC×GC modulation period was 4 s (hot pulse — 1.2 s, cold — 0.8 s). The transfer line temperature was maintained at 280 °C. Ionisation was performed by electron impact (EI, 70 eV); mass spectra were recorded at a rate of 200 spectra/s in the m/z 40–700 range. To exclude non-informative compounds, a data recording delay of 350 seconds was used.