### Ratio table

The ratio table contains isotope ratios and delta values calculated for each peak with three calculation methods applied to user-selected zones of the peak.

- point by point (PBP)
- linear regression slope (LRS)
- peak area integration (PAI)  

#### Explanation of the column names

| <div style="width:200px">Column name</div> | Description |
| :----------------- | :------------------------------------------------------------------------------------------ |
| Sample             | ID of the sample, helpful when several files are uploaded                                   |
| Isotopes           | ID of the detected peaks (number of peaks should be same when several files are uploaded)   |
| BL method          | name of the selected baseline correction method                                             |
| Ratio method       | name of the isotope ratio calculation method (PAI, PBP, or LRS)                             |
| Zone [%]           | peak zone used for the isotope ratio calculation                                            |
| Ratio P`n` `type`  | isotope ratio value of the peak. `n` and `type` specify peak ID and type, respectively      |
| Points P`n` `type` | number of points corresponding to the peak. `n` and `type` as above                         |
| Delta              | delta values calculated according to standard-sample bracketing method                      |
|                    | (detailed explanation below)                  |

#### Explanation of the buttons located above the table

| <div style="width:200px">Button name</div> | Description |
| :---------------- | :--------------------------------------------------------------- |
| Copy              | to copy the entire table                                         |
| Excel             | to save the table as Excel file                                  |
| add new zone      | specify an additional zone value for isotope ratio calculation   |
|                   | (default zone values are 100%, 95%, 90% and 80%)                 |
| rem selected zone | remove a previously selected zone                                |
| set coef          | enter coefficient for delta scaling (detailed explanation below) |
| Help              | get help                                                         |


#### Explanation of the delta scaling

***IsoCor*** gives possibility to perform delta scaling using scaling coefficient $f_{coef}$ in the equation below. 
The $f_{coef}$ value is added manually by the user after clicking the `set coef` button.   

$$\delta^{i/j}_{smp/std} = \left( {R^{i/j}_{smp} \over R^{i/j}_{work.std}} \right) \times f_{coef} - 1 ~~ \text{where:} ~~ f_{coef} = {1 \over \delta^{i/j}_{std/work.std} + 1 }  $$

Delta scaling is used when samples are measured against working standard, and the working standard is measured against reference material. 
Thus, when reporting delta values of the samples, conversion of sample delta against reference material is performed using above equation. 
If no scaling is needed, then $f_{coef}$ is set to 1 (default value).