MassDEP APH is the most confusing analytical method I have ever worked with—and the only one I've encountered that requires calculating calibration standards differently from actual client samples. I created a 14-minute animated tutorial explaining the Massachusetts DEP Air-Phase Petroleum Hydrocarbons (APH) Method. Although APH is based on EPA TO-15, its quantitation procedures are significantly different. The video covers: 🔬 Canister preparation, sampling and preconcentrat