Okay. I'll try to help you and get the data without any surrounding whitespace.

Here's your example once again in a monospace font:

  Acq On    : 18 Feb 2007  22:39                       Operator: FJN
  Sample    : Jones 1925 10                            Inst    : GC_MS

     1) 5aAndrostan-3a,17a-diol     11.24  241   186712   2500.00         0.02
    27) Stigmasterol                26.97  394     9158   2500.00 ng      0.02
    30) Cholesteryl Butyrate        30.59  368    23219   2500.00         0.02

First of all, a pattern to get the text from the labels:

Acq On    : (\d{1,2}\s\w+\s\d{4}\s+\d+:\d+)\s+Operator: (\S*)\s+Sample    : (.*?)(?=  )\s+Inst    : (\S*)

Then a pattern for  the xx) ... lines.

^ *(\d+)\) (.*?)(?=  | \d) +(\d+\.\d+) +(\d+) +(\d+) +(\d+\.\d+) +([a-z]*) +(\d+\.\d+)

using the multiline (m) modifier

I'm assuming you are using spaces not tabs in the text. I didn't know that else might show in the ng (nanogram?) column so I just allowed a string of lowercase latin characters. If there's no weight column the result in the respective match will simply be NULL.

Oh, and my best wishes to Mr or Mrs Jones: get well soon (I guess?)!

Thanks again for you quick response. I apologize for not explaining myself better. The data I extract will be placed in a database so I need to match each pattern separately. If I could see an example that grabs x amount of characters after the pattern or to the end of line I think I can get this done.

Are you saying that you (or Scodigo for that matter) can't use the match array as return value?

If you're using preg_match($pattern, $subject, $matches) for the header, $matches[1] should contain the acquiration date, $matches[2] the operator, $matches[3] the sample name and $matches[4] the "Inst" (who/whatever that is).

If you use preg_match_all($pattern, $subject, $matches) with the second pattern you should get a two dimensional array. $matches[0] will contain the data from the first line, $matches[1] the data from the second line and so on. To get the data columns you would use something like $matches[0][1] (leading number in front of bracket of first line), $matches[0][2] (pharmaceutical ingredient of first line) and so on.

If you really just want to match until you got a number of characters or the end of line use these patterns with activated multiline modifier (m) and without(!) singleline modifier.

Match a number of characters (in this example 18). This will catch trailing whitespace as well!

Acq On    : .{18}

Match to the end of line (without newline or carriage return characters or trailing whitespace):

Operator: (.*?)(?=\s*$)