EPA TO-4 Pesticides and PCB's
EPA TO-4 is the ambient air method for pesticides using a high volume (250 L/min) sampler with a quartz filter and PUF cartridge. The TO-10 method uses a smaller cartridge that is collected at a rate between 5 L/min and 20 L/min. The samples can be analyzed by gas chromatography (GC) with electron capture detection (ECD) and confirmed by using GC/MS. Regardless of the method used to collect the sample, the analysis method and QC Criteria is the same. At EAS we do the analysis by GC/MS only, in order to get a positive identification of the pesticides and avoiding false positives. If lower detection limits are needed the TO-4 SIM can be used which has a detection limit similar to the ECD.
Word about Method Detection Limits (MDL)
Defining Detection Limits
Detection Limits are used to specify the lowest concentration of a compound that can be measured reliably by the analytical method. There are several definitions for the detection limits used by laboratories so it is important to understand the differences, so that the objectives of your project are met. On this web site, the term detection limit is used as a general term to collectively describe the more specific terms such as the Method Detection Limit (MDL), Lower Quantitation Limit (LQL), Reporting Limit (RL), and Method Reporting Limit (MRL), and Practical Quantitation Limit (PQL).