NJDEP publishes low level air testing method

Environmental NEWS - Spring 2009

NJDEP has published a modification of USEPA Method TO-15 for the analysis of volatile organic compounds (VOC) in air samples using GC/MS. The new method, which is identified as NJDEP-LLTO-15–3/2007, may be found on the NJDEP website under their site remediation program. Lower reporting limits and additional quality control requirements are among the modifications to the original method.

The reporting limits published using the modified method are 2.5 times lower than the limits attained when using the unmodified USEPA method. The dynamic range of the method is increased by analyzing a standard curve that uses lower concentration standards at the bottom end and higher concentrations at the top end. However, increasing the range of the standards also makes it more difficult to meet calibration quality control requirements. The amended quality control sample criteria also present challenges. For example, the method includes a requirement to analyze a laboratory control sample at the limit of quantitation and recover a concentration that is within 30 percent of the true value.

Although some clarifications to the NJDEP document are still anticipated, Lancaster Laboratories is in the process of performing method validation work to demonstrate their capability to perform the method and plans to submit the data to the agency in an effort to add the low level method to their existing NJDEP certification. Lancaster Laboratories is one of only a handful of laboratories planning to pursue the certification. “We expect to submit our data package for certification once the clarifications are posted by NJDEP,” says Duane Luckenbill, director of Environmental Sciences. The ability to produce a compliant analytical data package that can be validated by NJDEP is part of the initial certification requirement for LLTO-15.