GC Simulator
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03 Chromatogram
Select a compound below to highlight its peak. Scroll to zoom, drag to pan, or double-click to fit. Click a resolution value to compare neighboring peaks.
Calculated column properties
04 Compounds & results
| Compound | Conc. µM | tR min | σ s | k′ at elution | On column pmol | Rs | Remove |
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Calculation model
At a constant oven temperature, retention time is tR = t0(1 + k′). The hold-up time, t0, comes from compressible carrier-gas flow through the column. Retention factors are interpolated from measurements on DB-5MS UI and adjusted for the column's phase ratio.
During a temperature program, the calculation follows each compound through the column as oven temperature, retention, and gas velocity change. The final temperature continues until elution or the 24-hour calculation limit. The chromatogram ends shortly after the last eluting peak, independently of the final programmed hold.
Column broadening uses the Golay equation for an open tubular column. Injection, gas decompression, and detector broadening contribute to the peak variance. The independent contributions add as variances: σ² = σ²column + σ²injection + σ²detector. Each compound produces a Gaussian peak with standard deviation σ; its approximate baseline width is 4σ. Resolution is Rs = |tR,2 − tR,1| / [2(σ1 + σ2)]. The table reports the smaller resolution to the adjacent eluting compounds.
The detector uses an ideal equal molar response for all compounds. Real detectors, including FID and MS, have compound-dependent responses. Diffusion parameters approximate a typical solute; adsorption, overload, and oven thermal lag are not modeled. Retention extrapolation outside measured temperatures is flagged.
The signal is sampled at equal time intervals, with fresh noise on each recalculation. Sampling is limited to 100,000 points; a warning appears if the run is truncated.