Concentrating on Chromatography

An unfamiliar peak. An inconclusive library search. A molecule that’s visible with one detector but missing from another. How do you figure out what’s actually in your sample?James Little joins David Oliva and Candi Gokey on Concentrating on Chromatography to explore the detective work behind identifying unknown compounds. Drawing on nearly five decades of mass spectrometry experience, including his career at Eastman Chemical and current work supporting NIST and Wiley’s spectral libraries and software, James explains how he combines chemical reasoning with GC-MS, LC-MS, and NMR.He shares the story of a mystery molecule whose electrospray signal disappeared in the presence of acetonitrile, recalls receiving a 55-gallon sample when he needed only a microliter, and explains why a top library match is a clue—not proof.In this episode:Why identifying one unknown peak starts with understanding the whole sample.When GC-MS and LC-MS provide complementary information.How accurate mass, isotope patterns, and hybrid library searches help narrow down possible structures.What NMR can resolve when mass spectrometry leaves multiple possibilities.How sample preparation and solvent choices influence what you detect.Why curiosity, persistence, and skepticism matter as much as the instruments.For chemistry students and laboratory scientists alike, this conversation offers an inside look at how an experienced analytical chemist turns unfamiliar data into defensible answers.Spotify description

Undergraduate researcher Kody Coyne is building a safer, hydrazine-free way to make nitrogen–nitrogen, nitrogen–oxygen, and nitrogen–sulfur bonds. Because every product is a brand-new compound, he has to invent the chromatography method to purify it.Kody is a biochemistry major and varsity swimmer at Monmouth College. In this episode he explains how he uses a custom C18 reversed-phase HPLC method to identify his product peak. He then uses that same information to decide between reversed-phase and normal-phase flash chromatography. He also explains how he double-checks every result with HPLC, FTIR, and NMR, and what he learned when his older flash system reported a negative absorbance.In this episodeHow Kody learned Schlenk lines, flash chromatography, and HPLC by doing the work himselfHow he landed his research project through Monmouth's summer research programWhy the hydrazine-free bond chemistry could make drug synthesis cheaper and saferWhy novel compounds get flash chromatography first, with recrystallization tested laterHow a custom C18 HPLC method helps him pick the right flash stationary phase and gradientHow he uses HPLC to confirm which flash fractions contain productWhat a clean trace looks like, and why he doesn't trust any single instrumentWhy chromatography slows work on new molecules but not on well-documented onesWhy working under nitrogen keeps unwanted peaks out of the chromatogramThe hot dog cooked in a benchtop microwave synthesizerHis advice to undergraduates: don't wait until you're an expertIf you're an undergraduate about to run your first flash column or HPLC sample, his advice is simple: don't wait until you're an expert to start.Concentrating on Chromatography is hosted by David Oliva of Organomation.

Chris Freye, Ph.D., is a staff scientist in the High Explosives Science and Technology group at Los Alamos National Laboratory, where he uses GC×GC, UHPLC, UHPLC-IMS, and high-resolution mass spectrometry to study how high explosives and plastic-bonded explosives (PBXs) change over time.In this episode, Chris discusses his path from rock climbing in the Pacific Northwest to a PhD under GC×GC pioneer Robert Synovec at the University of Washington, and how that training shaped his current work at Los Alamos. He walks through the unique safety and security realities of national lab chemistry, from handling gram-scale samples to retrieving material from magazines holding thousands of pounds of explosives, and explains why sample prep always starts with the scientific question rather than the instrument.The conversation covers why LC has long been the gold standard for explosives analysis and why it only tells half the story, how his team developed vacuum GC×GC to elute volatile explosives before they decompose, and the accidental discovery that a GC inlet can double as an aging oven — compressing three-year explosive aging studies into two hours. Chris also explains why his team started finding PFAS in high explosives materials through fluoropolymer binders, the extraction method they had to invent after standard EPA protocols failed, and how chemometric tools like Alteration Analysis and Fisher ratio analysis let them distill billions of data points into a simple yes-or-no answer about chemical change.Whether you work in chromatography, mass spectrometry, materials science, or just want a rare look inside high-explosives research, this episode covers the instrumentation, the chemistry, and the day-to-day reality of the work.

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 lubricantsWhy personal-care products such as lotions and oils can complicate forensic interpretationThe limitations of conventional GC-MS for high-mass polymers such as PDMS and PEGHow DART-TOF mass spectrometry enables rapid screening of complex forensic samplesWhy extraction from cotton swabs and other evidence substrates remains a critical challengeHow solvent polarity affects recovery of lubricant componentsHow likelihood ratios, population studies, and retail-market data could help assess the rarity and evidentiary value of a recovered lubricant residuePractical advice for undergraduate students considering careers in forensic science and analytical chemistryDr. 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 BridgeHost: David OlivaPodcast: Concentrating on ChromatographyFollow 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 DobrecevichHosts: Candi Gokey and David Oliva