When DNA is absent, incomplete, or difficult to interpret, what other evidence can help forensic investigators make meaningful connections?

In this episode of Concentrating on Chromatography, David Oliva speaks with Dr. Candice Bridge of the University of Central Florida and the National Center for Forensic Science about the emerging field of forensic lubricant analysis.

Dr. Bridge explains how chemical residues from sexual lubricants can support sexual-assault investigations by helping connect a victim, suspect, condom wrapper, or crime scene—especially when a usable DNA profile is unavailable. She discusses why DNA is not always the “silver bullet” people expect, why preserving limited evidence is essential, and how forensic laboratories prioritize the least destructive analysis first.

The conversation also explores the analytical chemistry behind lubricant evidence:

• The chemical differences among water-, silicone-, oil-, and natural/edible-based lubricants
• Why personal-care products such as lotions and oils can complicate forensic interpretation
• The limitations of conventional GC-MS for high-mass polymers such as PDMS and PEG
• How DART-TOF mass spectrometry enables rapid screening of complex forensic samples
• Why extraction from cotton swabs and other evidence substrates remains a critical challenge
• How solvent polarity affects recovery of lubricant components
• How likelihood ratios, population studies, and retail-market data could help assess the rarity and evidentiary value of a recovered lubricant residue
• Practical advice for undergraduate students considering careers in forensic science and analytical chemistry

Dr. Bridge also shares why she chose an underdeveloped research area, what it takes to build a new forensic discipline, and why students should pursue socially important scientific questions—even when funding and established protocols have not yet caught up.

Guest: Dr. Candice Bridge
Host: David Oliva
Podcast: Concentrating on Chromatography

Follow the podcast for conversations on chromatography, mass spectrometry, forensic science, sample preparation, laboratory technology, and careers in analytical chemistry.

He built a gas chromatograph and mass spectrometer small enough to fit in a carry-on suitcase, then hauled it up a 43-meter tower in 100-degree Alabama heat to catch invisible forest chemicals in real time.

Austin "Augie" Dobrecevich, a PhD researcher at the University of Washington, joins Candi and David to break down how his ultra-fast GC captures a full chromatogram every single second, isomer-speciating the biogenic VOCs (like alpha-pinene, beta-pinene, and limonene) that trees release into the atmosphere. Those compounds don't just disappear; they react with ozone and each other, eventually seeding the massive summer thunderstorms that roll over the southeast.

Augie walks through why traditional chemical ionization mass spec struggles to tell chemical isomers apart, how his fast GC front end solves that blind spot, and the engineering trade-offs required to make the whole system run on less power than a vacuum cleaner. The conversation also opens up into where this technology could go next, from oceanographic research to coral reef VOC sampling, and closes with a candid look at the patent process: provisional patents, university tech transfer offices, IP strategy, and the leap from writing research papers to pitching a business case.

Whether you're deep into analytical chemistry or just curious how scientists are learning to read the invisible chemistry of a forest, this episode covers both the technical detail and the real story of turning a lab prototype into something the world might actually use.

Guest: Austin Dobrecevich

Hosts: Candi Gokey and David Oliva

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.