Arielle Cocozza, National Technical PFAS Lead at ALS USA Environmental, joins David Oliva and Candi Gokey to break down the current state of PFAS analysis — from her unconventional path out of a physics degree into environmental chemistry, to standardizing PFAS methods across a national lab network.In this episode, Arielle explains what PFAS actually are and why their fluorine-carbon bonds make them so persistent, walks through LC-MS/MS vs. GC-MS/MS selection for different PFAS classes (including fluorotelomer alcohols and volatile fluorocarbons), and discusses column chemistry choices like C18 and pentafluorophenyl phases. The conversation dives deep into 6PPD-quinone — the tire-wear-particle degradation product linked to coho salmon die-offs — and how EPA fast-tracked Draft Method 1634 in response. Arielle also covers the Total Oxidizable Precursor (TOP) assay, EPA's new ultra-short direct-injection Method 1633/563 workflows, sample volume miniaturization, automation trends in extraction, and the patchwork of state-by-state PFAS regulations on food packaging and biosolids ahead of federal rulemaking.