Detecting volatile chemicals


I am interested in the volatile chemicals produced from bacteria, especially those from OP50. I’d like to detect them, such as diacetyl, 2,3-pentanedione that are widely used as odorants for C. elegans, from bacteria-free extract. However, I couldn’t find the right methods for the detection of them. Does anybody know which approach should I try? Or are there any companies that provide such services?
I really appreciate your answer.
Thank you!