Peter W. Carr (1944–2025): A Personal Tribute

Although Professor Peter Carr was a late-comer to the field—a self-labelled “recovering electrochemist”—he was widely recognized for both the breadth and depth of his knowledge and contributions. A more thorough summary of his professional achievements can be found in a recent tribute in the Journal of Chromatography A.¹ What follows here are personal anecdotes from some of Pete’s close collaborators and friends, recalling Pete’s intellectual and technical achievements and the way he touched many of us personally and professionally.

I first met Pete when I started working with ZirChrom Separations, Inc. in 1999, where he was president of the company. In those interactions, I quickly learned about his intensity in all things—ranging from science, to fishing, to history—and an unrelenting attention to detail. As a result, we got along very well, and over the next few years, he turned me into a chromatographer, guiding me to a Ph.D. in 2007. I especially appreciated his focus on precision in communication and was privileged to have written a lot with him. As so many others have written below, it will take me a long time to get used to the fact that I cannot just call him to ask questions about an idea, an equation, or life advice.

Mark Schure, Kroungold Analytical

“Pete Carr was a mentor of mine. One of the many things Pete did was to bring my future coworker Ilja Siepmann and I together. Ilja was hired as an assistant professor at the University of Minnesota, and Pete realized that Ilja’s simulation methods could be extremely complementary to my molecular modeling work on reversed-phase LC. Pete and coworkers had done key experiments using hexadecane as an analog to the C18 stationary phase. They were able to determine the thermodynamics of small solutes in the solvent and in the hexadecane phase, and they showed the essential lipophilic driving force in RPLC. We simulated the hexadecane experiment and showed very good agreement with the Carr group results. Ilja and I have continued this research, producing over 30 papers on the fundamental science of LC over the past 30 years.

Pete also included me in many 2D chromatography discussions as he and Dwight began making 2D a fast, high-performing method. Pete felt a commitment to develop many initial works into maturity when he saw the direction these research pieces might take. He was visionary and was able to see the interdisciplinary nature of separation science clearly.”

Xiaoli Wang, Agilent Technologies

“I feel incredibly lucky to have learned from Pete. Studying under Pete was not just an education in chromatography, but an education in how to think, how to question, and how to grow. His scientific rigor shaped the way I approach research—guided by lessons he repeated often, such as ‘Theory guides, experiment decides,’ and ‘Never trust your first injection.’ But what made Pete truly special was how deeply he cared about his students beyond the lab. He taught us how to communicate clearly, how to develop confidence and personal skills, and how to build lasting networks of support. Pete used to say that his greatest and most lasting impact was on the people he mentored, and I feel immense gratitude and pride knowing that I was one of them.”

Peter Schoenmakers, University of Amsterdam

“The first time I met Pete Carr at a chromatography conference, and we engaged in a conversation—it must have been some 25 or 30 years ago—he sort of apologized for not being a real chromatographer. It was long before I realized that many years earlier, as a student, I had been spelling out and citing a famous paper by Mark Watson and the very same Peter Carr on Simplex optimization of gradient LC separations. Pretending not to be a real expert gave Pete an excuse to ask all kinds of inquisitive questions, something he loved to do. Pete’s big quest was to gain understanding, which he then conveyed masterfully in papers and lectures. He could not hide long from being recognized as the great chromatographer he was.”

William Barber, Agilent Technologies (retired)

“Pete had a tremendous impact on my educational training, my career, as a collaborator during my time at Agilent, and as a dear friend for nearly five decades. As my Ph.D. adviser, Pete was a wonderful mentor throughout my graduate research. During several research setbacks, he provided encouragement and showed me how to look for opportunities when things didn’t go exactly as planned. After the University of Minnesota (UMN), I was able to maintain my friendship and professional relationship with Pete when I became the Hercules campus recruiter at UMN. Then, and later at Agilent, I had the good fortune to hire some of his top students. At Agilent, I was able to provide equipment, supplies and funding to support various group projects. The most significant of these was the basic science that Pete, Dwight Stoll, and several other students developed that ultimately led to the introduction of the Agilent 2D LC instrument. The technical discussions during many project reviews at UMN and with my instrument colleagues in Germany were a great model for an academic-industry collaborative effort. Finally, I will really miss the random Saturday afternoon phone calls from Pete to throw out an idea and just talk science for a while.”

Stephen Weber, University of Pittsburgh

“I sought Pete out at an ACS meeting in the ‘80s. He was boisterous, funny, and ate one-pound steaks for lunch! At some point in the ‘80s, I was writing a chapter on bandspreading for a book. I needed help, so I called Pete. It turns out that he was in traction, more or less immobilized, having had an injury. He was thrilled to have something productive to do. Many conversations over many weeks helped me to understand Pete’s brilliance and his passion for getting things right—in every detail.

Pete was generous. He promoted younger colleagues. He gave full credit to his forebears and contemporaries in conversations and publications, acknowledging and appreciating their contributions.

Pete was a deep thinker. On the surface, he seemed less of a scholar than a wise storyteller. But in many conversations about separations, mostly the kinetic aspects, he taught me an enormous amount about the dynamics of chromatography. This helped me in my work and especially in my teaching. I really miss him.”

John Dolan, LC Resources (retired)

“In the early days of LC Resources, when we were first developing our DryLab software, we didn’t have a laboratory to do our own data gathering. Pete ‘volunteered’ to help us by assigning a graduate student to run critical experiments that he and Lloyd Snyder designed. These were the foundation of the software, and the data are used today as the default dataset for users. Later, as I became involved with the Minnesota Chromatography Forum, I was invited to join Pete’s circle of friends for a wine-and-cheese discussion group on his back deck each spring. Here, I saw the reverence his past graduate students had for their mentor. I also learned some of the ‘Pete-isms’ that he spontaneously uttered—the quote from Schoorl, ‘Theory guides; experiment decides,’ ‘Show me the data,’ and the recommendation that if one has the choice of two words when writing, choose the one with fewer letters. Pete was a great friend and colleague—his shoes will be hard to fill.”

Yun Mao, Bristol Myers Squibb

“Professor Peter Carr shaped my life in ways I am still discovering. When I joined his group in 1996, arriving from China with tentative English and fragile confidence, Pete saw potential in me long before I could see it in myself. He didn't just teach chromatography, he taught me to think boldly, work with purpose, and believe I could contribute meaningfully to science and the world beyond. His mentorship never ended. For decades, Pete remained a steady presence, offering encouragement, wisdom, and genuine warmth through every career milestone and personal challenge. Helping organize his 70th and 81st birthday celebrations became a profound privilege, one small way to honor the immeasurable impact he had on so many of us. At his final celebration, Pete told us that the tributes from his students meant more than any award he'd ever received, a testament to the values he lived by every day. Pete measured success not in publications or accolades, but in people. I am forever grateful to be one of them.”

Sarah Rutan, Virginia Commonwealth University

“I was a third-year assistant professor at Virginia Commonwealth University and had had no post-doctoral experience. My senior colleague at VCU and a program officer at NSF schemed to get me a ‘sabbatical leave’ (i.e., a late post-doc) with Pete for eight months in 1988, and I met Pete for the first time at a small solvatochromic conference prior to the sabbatical. I was still learning how to conduct research and write papers, and Pete’s critiques of the manuscripts I wrote with him in 1988 were invaluable. Over the years, I have collaborated with him many times, and I am his second-most-frequent coauthor (second only to Dwight Stoll!). I am also coauthor with Pete on his last scientific publication in 2021. That paper had a lot of messy equations and took a long time to write—I think I made Pete review at least six or seven drafts to make sure all the equations were correct! Besides this long-term scientific partnership, he was one of my oldest friends, and I was honored that he considered me ‘the little sister he never had.’ I miss him dearly.”

Gert Desmet, Vrije Universiteit Brussel

“My first encounters with Pete Carr were by reading his papers. These stood out by their clarity, theoretical soundness, and educational value and were hence the perfect introduction to the field. Later, I got into a virtual relationship with him through Agilent’s Monika Dittmann, with whom we frequently collaborated. And very often, she (rightfully) closed a discussion by saying ‘Yes, but, according to Pete Carr’s paper, this is probably what it will/should be.’ And indeed, that’s also how it always turned out to be. I therefore consider Pete as one of the most undervalued people in the field.

I hence really regret my first ‘live’ encounter with Pete Carr happened relatively late in his career, but I will never forget how we sat down. Me being a little nervous about being face to face with one of my heroes, but as soon as we started talking about the importance of particle size dispersion, I felt we were kindred spirits. And this was a very fulfilling feeling for me. My physical encounters with Pete remained scarce, but we used to have periods with a fierce email correspondence, wherein he bombarded me with pages and pages of mathematics to test theories. I consider these moments behind my computer, anxiously opening his mails and then discovering a treasure of mathematical derivations, written in his beautiful handwriting, as true privileges and thus highlights in my career.”

Acknowledgement

I’d like to thank Prof. Mark Vitha for his help with the crafting and editing of this tribute.

Reference

1. Stoll, D.; Vitha, M. Tribute for Professor Peter W. Carr. J Chrom A 2026, In Press, 466779. DOI: 10.1016/j.chroma.2026.466779