Editor's Note: This article was prepared in cooperation with John M. Riviello, formerly of Dionex and Thermo Fisher, and a colleague of Christopher Pohl.
Scientist and inventor Christopher Pohl, no stranger to receiving awards, has been honored with the American Chemical Society Award 2023 in Chromatography. The award ceremony took place March 28 during the spring meeting of the American Chemical Society (ACS) in Indianapolis, Ind. A special symposium in honor of Pohl organized by Professor Purnendu K. (Sandy) Dasgupta, from University of Texas at Arlington, will be a part of ACS Fall 2023 in August, in San Francisco.
Pohl spent 45 years in the industrial sector researching and developing technologies and products in all aspects of ion chromatography (IC). As the Vice President of Chromatography Chemistry at the Chromatography and Mass Spectrometry Division of Thermo Fisher Scientific, and previously at Dionex Corporation, he led the development of IC separation and detection technologies, as well as a variety of sample preparation products, which fueled the commercial growth success of IC.
Pohl was the technology innovator and driving force for the development of more than 50 unique polymeric stationary phases and IC columns for various applications. His inventions in stationary phase design remain the core separation technology for IC analysis of small ions. Additionally, those novel ion-exchange phases also have gained significant commercial success outside the traditional IC market for high-performance separations of proteins, nucleic acids and carbohydrates.
Pohl is an author or co-author of 105 US patents with numerous foreign equivalents in several areas including separation methods, stationary phase design, suppressor technology, solid-phase extraction, capillary electrophoresis techniques, methods of calibration, mixers, and accelerated solvent extraction (ASE). His knowledge and contributions to separation science are captured in 149 manuscripts in peer-reviewed journals, 14 book chapters on IC stationary phase design, mechanisms, consumables, and applications and in the most recent monograph on IC instrumentation and techniques. Pohl’s most significant accomplishments are listed below:
Pohl’s first contribution to IC began soon after the commercial introduction of the method in 1975. As an analytical chemist at the Clorox Company, he was intrigued by this new technique of ion analysis. Clorox’s resistance to purchase a commercial IC resulted in Pohl developing a “suppressible” ion pair method using a polymeric reversed-phase column . Pohl reduced this to practice, and it was this work that landed him his first R&D job at Dionex. Eventually, Dionex commercialized this new technique as mobile phase ion chromatography (MPIC).
In 1982, within collaboration of Dionex with Prof. Dennis Johnson, Pohl was working on the separation of carbohydrates in IC mode with electrochemical detection. He discovered that the best separation of carbohydrates could be achieved using high pH eluents instead of moderate pH borate eluents used at that time and realized that carbohydrate separation could proceed without borate based on completely different mechanism . Pohl’s findings and mechanism interpretation for retention and separation of carbohydrates with anion-exchange chromatography at high pH led to the development of unique high-performance CarboPac column series belonging to the Dionex/Thermo Fisher Scientific portfolio.
Since the inception of IC, hydroxide eluents were recognized as being ideal for use with conductivity detection. In coordination with Hamish Small and the development of electrolytic eluent generation, Pohl pioneered the development of hydroxide selective stationary phases . His research on anion-exchange stationary phases behavior led to the observation that incorporation of one or more ethanol substituents in the quaternary ammonium site makes hydroxide a more effective eluent for the separation of anions.
This finding resulted in several advantages for ion analysis by IC: First, lower detection limits became achievable with hydroxide eluent as compared to carbonate eluent due to lower suppressed background conductivity of hydroxide. Second, hydroxide eluent provides a linear calibration curve, while carbonic acid formed after suppression of carbonate may affect linearity if operating in a wide range of concentrations. Third, development of numerous anion-exchangers suitable for gradient ion chromatography applications became possible, which allowed the analysis of mono- and polyvalent anions in one run and significantly broadened the range of suppressed IC applications. As a result, electrolytic hydroxide eluent generation and the range of hydroxide-selective stationary phases developed under Pohl’s guidance are the dominant form of gradient technology used in IC today.
The development of hydroxide-selective IC columns was the driving force for the suppressors compatible with the higher eluent concentrations. Pohl led the development of the first commercial flat membrane suppressor at Dionex and was a co-inventor of the first Dionex patent covering the flat membrane suppressor . This patent covered a critical component that helped Dionex dominate the IC market and remains the core suppression technology sold by Thermo Fisher Scientific with every ion chromatograph today.
In 1998, Dionex acquired Lee Scientific, a company commercializing supercritical chromatography (SFC) and supercritical fluid extraction (SFE). Pohl recognized the limitations of supercritical fluids and led the development of a new technique for extracting trace components from solid and semi-solid samples under elevated pressures and temperatures. The new technique, Accelerated Solvent Extraction (ASE) , was patented and commercialized by Dionex, and remains a successful sample preparation tool today.
Pohl’s development of hyperbranching technology based on forming step-growth polymer coatings  on the sulfonated substrate surface became a significant breakthrough in the anion-exchange stationary phase design for IC. The major advantages of hyperbranching process include ease of selectivity and capacity optimization, which makes this technology the most versatile stationary phase chemistry platform in IC. Nowadays, hyperbranched anion exchangers represent a significant part of Thermo Fisher Scientific IC column portfolio and are known for their exceptionally high performance.
As a prolific inventor and a mentor to many industrial chemists, Pohl has left an indelible mark in the field of IC and analytical chemistry. His dedication and passion to science made him a great role model and source of motivation and inspiration for his co-workers and other members of separation science community worldwide. Pohl’s inventions, from sample preparation to separation and detection, are responsible for making IC an essential technique in the analytical chemists’ toolbox and are supporting global laboratory workflows using Innovative ion chromatography systems every day for a variety of analytical applications.
Pohl’s contribution to IC was recognized by several prestigious awards, including: International Ion Chromatography Symposium Award (1990); Uwe Neue Award (2018); Eastern Analytical Symposium Separation Science Award (2018); and George N. Hatsopoulos Technical Innovation Award from Thermo Fisher Scientific (2020). Nominated by Prof. Dasgupta, Pohl became the second industrial chemist in over 60-years-long history of ACS National Awards to receive an award in Chromatography. The fact that the first industrial chemist acknowledged with such an award was “the father” of IC, Hamish Small himself (in 1991), makes this achievement even more significant.
Thank you for all of the great IC column, eluent generator, and suppressors!
Congratulations on outstanding achievement, Chris!
The world of Ion Chromatography wouldn’t be the same without your contributions. Your journey as a Scientist is amazing and I’m glad that I was able to witness at least a small fraction of it!
Congrats Chris! Your ideas have materialized into many products that are best in class. Thank you for all that you have done over the years.
I cannot think of anyone who has made a greater impact on the field of Ion Chromatography, nor who is more deserving of this award. Congrats Chris!
Congratulations Chris for adding one more to your numerous many achievements!! Your contributions to the field of Ion Chromatography are so plentiful that your name can easily be the synonym to Ion Chromatography. Feeling proud and happy working with you.
Chris - Congratulations on this well-deserved recognition. I am grateful for the opportunity to work with you and look forward to seeing all that you will accomplish in the future.
Congratulations on this well-deserved recognition, Chris! The world of Ion Chromatography would have been a poorer place without your significant impact. Thank you and good luck with your future accomplishments!
Congratulations Chris, you deserve this !
So lucky to meet you at the 2023 ACS Spring meeting in Indianapolis.
Congratulations Chris! Well deserved but you are my second favorite IC pioneer 😁. Obviously, my favorite is Hamish Small (god bless his soul, RIP). 👏🙌🙏
Congratulations Chris on this incredible award! It is a testimonial to your accomplishments and success.
What an accomplishment, congratulations Chris!!!
When you hired me in R&D, it wasn’t even in my wildest dreams that I get to work so close with an Ion Chromatography legend. Thank you for giving me the opportunity to work with you on so many stationary phase advances you brought to life for countless customer application.
Thanks for all what you have done for Ion Chromatography and providing customer with solution for their analytical challenges!!!
Congratulations Chris on yet another achievement. It speaks volumes of your contribution to Chromatography applications be it stationary phases and be it the analytical tools surrounding them. Kudos to your contribution to separation science for a cleaner, safer and healthier world.
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