Here is a very important trip especially if you're trying to include a quotation mark as part of concatenation to write a command that helps you write HTML code. Without this tip, every time you try to place your quotation mark it becomes part of your command structure of the code
To concatenate a quote mark in a calculation formula, type four quote marks.
For example, enter this formula into a calculation field, resulting in text:
FirstName & "^" & """" & Bosco & """" & "^" & LastName
(In this example, the FirstName field is concatenated with a double-quote character, etc. You should type a space where you see a caret (^) in this formula.) You don't actually put the caret in this code example.
The sample output from this formula is as such:
Jonathan "Bosco" Doe
Note: Beginning with FileMaker Pro 7, you can also use "\"" to insert a quote.
SOURCE:
FileMaker Concatenating a Quote Mark in a Calculation Formula