James Lovelock, inventor of the Electron Capture Detector, passed away earlier this week at the age of 103.
27 Jul 2022James Lovelock passed away on Tuesday, July 26, 2022, his 103rd birthday. The New York Times published an excellent obituary here. I thought that I would focus on some of the lesser-known details around his invention of the Electron Capture Detector (ECD), which Lovelock himself shared at PittCon’s first James L. Waters Symposium.
In the early 1950’s, Lovelock was working at the prestigious National Institute for Medical Research (NIMR), sharing ideas with the United Kingdom’s best physicists, chemists, biologists and doctors. Working in experimental biology, one floor down from where Archer Martin and Tony James were working on their newly invented Gas Chromatograph (GC). He was tasked with discovering how the freezing process damages living tissue, and how to prevent it. His group figured out how to revive frozen hamsters. The trick was to heat the heart faster than the surrounding tissues so that there was still oxygenated blood available to fuel its beating. To do this, he cobbled together a primitive microwave using a 500-watt continuous wave magnetron borrowed from the Navy. This was standard practice at NIMR, where researchers were expected to build the equipment needed for experiments. This is the environment that the ECD was invented in; one of basic need for a sensitive detector.
Lovelock suspected that tissue sensitivity to freezing damage was tied to the fatty acid composition of the cell membrane lipids. He spent two months freezing tissues, extracting, and purifying fatty acids, planning to analyze them with the new GC. His purified yield of fatty acids was only a few hundred micrograms, not enough to meet the sensitivity limits of the GC’s detector. Rather than spending months extracting additional sample, Lovelock decided to make a more sensitive GC detector. He had already made an ionization anemometer that detected CFCs and cigarette smoke – significant interferences when measuring air velocities, but a good start for a GC detector. Building on this anemometer design and the ionization cross section detector developed at Shell Labs, unencumbered by any Environmental Health and Safety regulations, he made a simple cylindrical ion chamber with a strontium 90 β+ source (Figure 1).
All obstacles overcome, Lovelock was able to analyze his fatty acid sample, and his hard work was rewarded with “vast peaks appear[ing] from a tiny sample.” However, these peaks were not at the fatty acid retention times. The vast peaks were trace CFC contamination. This is how modern day Persistent Organic Pollutant (POPs) analysis was born. Lovelock had made a detector so “exquisite[ly] sensitive” for halogenated compounds that they were found everywhere one looked.
Figure 1 - James Lovelock's ECD