Calib Curve Plot by compound

Thank you very much Martin Again. I added this function that Colefunk suggested. In our example here, there is no issue because we don't have negative slope. But If we use MHE (Multiple Headspace extraction in future, since it's a Log curve, we will have a negative slope and so this function will help. Can you explain me the meaning of " IR are VB?" How can I know tha I have to change data type to a string? I'm not a programmer, sorry, I'm just a chemist. lol  

Hello,

It means that the expressions you create in IR are in visual basic (VB) syntax. This allows use of standard programming functions that are familiar to anyone that has used VB. It also means that if you are trying to do something in the software expressions, you can search the internet for advice and information on VB syntax that will be applicable. I am not sure how to explain data types in this context. For example, I want to embed a RT value in a text string on a report.  I know that the RT is a numeric value so if I try ="My test peak is at " & Peak_RetentionTime it will give an error as it cannot add a numeric value to a string. However, I could use ="My test peak is at " & Cstr(Peak_RetentionTime) instead and I would get a valid returned string. Please note in some cases the first example would work in more recent versions as the renderer has some ability now to convert data types automatically. When I see the resultant output and the RT has 15 decimal places I might lookup formatiing strings in VB on the internet and find the function formatnumber. Using that function, I would change the expression to ="My test peak is at " & FormatNumber(Cstr(Peak_RetentionTime),3) to get the final output I wanted. 

Marty