In IsoCor: Analyze Isotope Ratios in a 'Shiny'-App

IDMS table

The table includes the following information:\ - Sample: ID of the sample; each file is indexed when several files are uploaded\ - Peak ID: ID of the detected peaks (when several files are uploaded, the files should contain same number of peaks); each detected peak is indexed numerically\ - RT max: retention time of the peak at maximum intensity\ - RT start: retention time at the start of the peak\ - RT end: retention time at the end of the peak\ - Scan start: index of the row corresponding to the start of the peak\ - Scan end: index of the row corresponding to the end of the peak\ - Scan length: number of points corresponding to the peak elution from start to the end\ - Mass bias method: Name of the method when mass bias correction is applied; default name "none"\ - f_value: a coefficient for mass bias correction; the coefficient should be calculated separately and copy/pasted into IsoCor; find detailed explanation below\ - k: mass bias correction factor calculated by the IsoCor; find detailed explanation below\ - Abs_q is absolute quantity of the element found by integration of the corresponding peak\ - Conc is concentration of the element found using injection volume.

Explanation of the buttons located above the table:

CSV: to save table in CSV format
Excel: to save the table as Excel file

Mass flow (MF) calculation formula:

$MF_{sample}=MF_{spike}\frac{(Abund.MI_{spike}-IRKAbund.SI_{spike})}{(IRK*Abund.SI_{sample}-Abund.MI_{sample})}-MF_{blank}$

Quantification formula:

$C=\frac{\sum (MF_{peak}*\Delta t)}{V_{inj}}$

Explanation of the formula parameters:

The parameters that are calculated by the app:\ $MF_{sample}$ is mass flow of the sample;\ $IR$ is isotope ratio calculated according to $IR=\frac{Intensity(MI)}{Intensity(SI)}$, where MI is a main isotope, SI is a secondary isotope;\ $K$ is mass bias correction factor in the $IR_{corrected}=IR_{measured}*K$; the K can be calculated using one of three mass bias calculation methods selected by the user from the dropdown menu;\ $MF_{blank}$ is mass flow of the blank. The blank is estimated by the app and subtracted from the raw MF to obtain baseline corrected MF;

The parameters that are inserted manually by the user:\ $MF_{spike}$ is mass flow of the spike;\ $Abund.MI_{spike}$ and $Abund.SI_{spike}$ are abundance of MI and SI, respectively, in the spike;\ $Abund.MI_{sample}$ and $Abund.SI_{sample}$ are abundance of MI and SI, respectively, in the sample;\ $V_{inj}$ is an injection volume\