“Most of the work still to be done in science and the useful arts is precisely that which needs the knowledge and cooperation of many scientists . . . that is why it is necessary for scientists and technologists to meet . . . Even in those branches of knowledge which seem to have least relation and connection with one another.”

–Antoine Lavoisier, Reflexions sur L’instruction Publique, 1793

David Michael Hercules passed away January 20, 2024, following a battle with cancer. David was born August 10, 1932, and spent his childhood in rural Pennsylvania. He developed his interest in science very early with the gift of a chemistry set and enjoyed tinkering with electronics. In addition to science, David was very interested in music, playing the cornet and French horn through high school and college. He considered pursuing a career in music, but science won out (Fig. 1).

Photo of David M. Hercules, 2023

David received his Bachelor’s in Science at Juniata College in Huntingdon, PA in 1954. He then received his Ph.D. in analytical chemistry from Massachusetts Institute of Technology (MIT) under the tutelage of Lockhart “Buck” Rogers. David’s academic pedigree can be traced back to Etienne de Clave, professor at the Jardin du Roi in Paris (Fig. 2). After completing his Ph.D., he joined the chemistry faculty at Juniata (1960–63) and then at MIT (1963–69), followed by positions at the University of Georgia, the University of Pittsburgh, and Vanderbilt University. At Pittsburgh and Vanderbilt David led the chemistry departments, developing a reputation for being fierce yet fair. Throughout his career, David earned many honors and awards including the Spectroscopy Society of Pittsburgh Award (1996), the American Chemical Society National Award in Surface Chemistry (1993), the American Chemical Society National Award in Analytical Chemistry (1986), and the Alexander von Humboldt Prize (1983) where he collaborated over a several year period with Professor Alfred Benninghoven at the University of Münster. He was a prolific writer, publishing over 500 research articles and garnering > 17,000 citations. He enjoyed teaching as well as research, receiving the Excellence in Teaching Award from the Student Affiliates of the American Chemical Society.

Academic Lineage of David M. Hercules (Design by Alexandria Sohn, Academic Granddaughter of David M. Hercules)

David was the quintessential Renaissance scientist, constantly pushing himself and others to explore new avenues of applied science. He taught the scientists around him to challenge assumptions and consider new ways of thinking. He often stressed the importance of embracing and understanding new analytical tools and expanding the capabilities of existing tools to enable solving even more complex questions. His scientific career was ever changing—early in his career he explored chemiluminescence and pioneered bioassays for measuring glucose in blood and was the first to observe electrochemilumescence, the generation of chemiluminescence from electrochemically generated species (Science, 1964, 145, 808–809). He then moved into surface science, materials characterization and catalysis, developing and applying numerous techniques including electron spectroscopy for chemical analysis (ESCA), Mössbauer Spectroscopy, ion scattering spectroscopy (ISS), dynamic and static secondary ion mass spectrometry (SIMS), extended X-ray absorption fine structure (EXAFS), and Auger electron spectroscopy (AES). He then pivoted to mass spectrometry techniques including Time of Flight-SIMS, laser microprobe mass analysis and Matrix Assisted Laser Desorption/Ionization (MALDI). He also ensured that future generations would understand the fundamentals of these techniques by writing educational pieces, all of which have withstood the test of time (J. Chem. Ed., 1984, 61, 592; J. Chem. Ed., 1984, 61, 6, 483; J. Chem. Ed., 1984, 61, 5, 402.). David is often credited (with others) in building the foundation in the burgeoning area of polymer mass spectrometry (J. Chem. Ed., 2007, 84, 81–90). This eventually led him back to his bioassay beginnings where he developed and applied TOF–SIMS and MALDI-TOF mass spectrometry to address important biological problems (Mass Spectrom. Rev., 1995, 14, 6, 383–429). He would always say his career was a “random walk” through analytical chemistry. However, arguably his most significant accomplishment was mentoring of more than 130 graduate students and post-docs, teaching them to be scholars and leaders. (Fig. 3).

Group Meeting, Department of Chemistry, University of Pittsburgh, circa early 1990’s

One of his mantras was that any measurement was worthless without a confirmatory technique as a reference. We often lose sight of this fundamental premise, becoming overly enamored with the wealth of data obtained from sophisticated analytical instrumentation. Dave ignored this glamour, relentlessly focusing on confirming or rejecting the hypothesis in question and moving on to the next.

Due to the breadth of Dave’s scientific interests, he was engaged in a host of industrial collaborations across a variety of areas including chemistry, polymers, clean energy and medicine. He consulted for the Central Intelligence Agency, Exxon Mobil, instrument laboratories, and W. S. Merrill and Company. His research group included graduate students, postdocs, visiting scientists and emeritus professors from academic, industrial and government institutions. Thanks to his Humboldt fellowship and consulting roles, this diversity was truly global, including scientists from Japan to Germany. He encouraged us all to build our own expansive networks, and connected his students to the best opportunities in academia and industry.

Rather than micromanaging, Dave practiced benign neglect to encourage autonomy and independent scientific inquiry in his group members. However, he did hold us accountable to make progress against our objectives, and would critically, and incisively, assess our manuscripts, research proposals and presentations in our weekly group meetings. He held himself to even higher standards—always raising his own bar in relentless pursuit of scientific scholarship and impact.

Dave’s greatest strengths, ultimately, were his authenticity and warmth. Even after his students graduated, he was only a phone call or e-mail away, providing sage advice, humor and compassion to help us navigate various challenges in our careers and personal lives. Of all the faculty and leadership positions he held over the years, he took his role as our academic father most seriously.

His tenacity, scholarship, and raw intellect contributed to numerous and disparate fields. Many of these disciples assembled at Vanderbilt on the occasion of Dave’s 70th birthday in 2002 (Fig. 4) and contributed to a special issue dedicated to his career entitled “Advances in Optical Spectroscopy and Mass Spectrometry” (Anal. Bional. Chem., 2002, 373, 7).

70th Birthday Celebration and Scientific Symposium for David M. Hercules, Department of Chemistry, Vanderbilt University, 2002