Recently, I received an interesting email from Steve Jones, PhD, the owner of Jones Environmental laboratories. Among other interesting and insightful things he discussed, there was also a brief discussion on Selective Ion Monitoring analysis. I have included a segment of his email here for your info. If you have further questions or comments for Steve, I am sure he would love to hear from you and his contact info is at the end of this article.
We have been receiving many requests for low detection limits in soil gas and indoor air analyses. Because we use a different type of mass spectrometer than all of our competitors, we are able to reach detection limits without the need for SIM (Select Ion Monitoring) procedure. SIM mode is not as well suited for determining which compounds are present and should be discouraged unless the site is well characterized using previous information. One common exception to this would be PAHs. PAHs require very low detection limits and require SIM mode, not matter the mass spectrometer used. Our stationary laboratory also has TO-15 capability; very low indoor air detection limits in the part per trillion range are routine for us. A part per trillion is the equivalent of the thickness of a piece of paper per the width of the United States!