title: Check if a text string contains special characters in excel
body: <p>As the title already mentioned, I want to check if a certain text string contains any special characters. </p>
  
  <p>Currently I have created a column with the characters which are allowed (ASCII range 32-122). And I would like a formula which returns 'ok', if the cell only contains characters which are allowed and 'not ok' if the cell contains any character that is not allowed.</p>
  
  <p>However, Is this even possible without using a for loop? (thus without vba)</p>