The 2007 Benjamin Franklin Medal in Chemistry Presented to Klaus Biemann, Ph.D., of The Massachusetts Institute of Technology Cambridge, Massachusetts

In 1886, Goldstein observed that when the cathode in a vacuum tube was pierced with holes, the electrical discharge did not stop at the cathode; behind the cathode, beams of light could be seen streaming through the holes in the way represented in Figure 1. He ascribed these pencils of light to rays passing through the holes into the gas behind the cathode; and from their association with the channels through the cathode he called these rays Kanalstrahlen. The colour of the light behind the cathode depends on the gas in the tube: with air the light is yellowish, with hydrogen rose colour, with neon the gorgeous neon red, the effects with this gas being exceedingly striking. The rays produce phosphorescence when they strike against the walls of the tube; they also affect a photographic plate. Goldstein could not detect any deflection when a permanent magnet was held near the rays. In 1898, however, W. Wein, by the use of very powerful magnetic fields, deflected these rays and showed that some of them were positively charged; by measuring the electric and magnetic deflections he proved that the masses of the particles in these rays were comparable with the masses of atoms of hydrogen, and thus were more than a thousand times the mass of a particle in the cathode ray. The composition of these positive rays is much more complex than that of the cathode rays, for whereas the particles in the cathode rays are all of the same kind, there are in the positive rays many different kinds of particles. We can, however, by the following method sort these particles out, determine what kind of particles are present, and the velocities with which they are moving. Suppose that a pencil of these rays is moving parallel to the axis of x, striking a plane a right angles to their path at the point O; if before they reach the plane they are acted on by an electric force parallel to the axis of y, the spot where a particle strikes the plane will be deflected parallel to y through a distance y given by the equation

IN 1886 Goldstein discovered that when the kathode in a discharge-tube is perforated, rays pass through the openings and produce luminosity in the gas behind the kathode; the colour of the light depends on the gas with which the tube is filled, and coincides with the colour of the velvety glow which occurs immediately in front of the kathode. The appearance of these rays is indicated in Fig. 1, the anode being to the left of the kathode KK. Since the rays appeared through narrow channels in the kathode, Goldstein called them “Kanalstrahlen”; now that we know more about their nature, “positive rays” would. I think, be a more appropriate name. Goldstein showed that a magnetic force which would deflect kathode rays to a very considerable extent was quite without effect on the “Kanalstrahlen.” By using intense magnetic fields, W. Wien showed that these rays could be deflected, and that the deflection was in the opposite direction to that of the kathode rays, indicating that these rays carry a positive charge of electricity. This was confirmed by measuring the electrical charge received by a vessel into which the rays passed through a small hole, and also by observing the direction in which they are deflected by an electric force. By measuring the deflections under magnetic and electric forces, Wien found by the usual methods the value of e/m and the velocity of the rays. He found for the maximum value of e/m the value of 104, which is the same as that for an atom of hydrogen in the electrolysis of solutions. A valuable summary of the properties of these rays is contained in a paper by Ewers (“Jahrbuch der Radioaktivität,” iii., p. 291, 1906).

ALL physicists and chemists, with many who, though less directly, are yet no less deeply interested in the subjects opened up by the study of the phenomena of the discharge tube, will rejoice that Sir J. J. Thomson has found time, amid his many preoccupations, to bring out this second edition of his well-known monograph on rays of positive electricity. The output of scientific work is now so enormous that it is difficult to keep pace with it even in one's own special line of study. It would be practi cally impossible, if it were not for the assistance given by books such as this, ever to come abreast once more of a subject in which one has once fallen behind. In writing this clear and authoritative account of the present state of a subject which he has done so much to develop, Sir J. J. Thomson has performed a real service to science. Rays of Positive Electricity and their Application to Chemical Analyses. By Sir J. J. Thomson. (Monographs on Physics.) Second edition. Pp. x+237+ix pl. (London: Longmans, Green and Co., 1921.) 16s. net.

Advances in mass spectrometry have facilitated the identification of novel lipid structures. In this work, we fractionated the lipids of Escherichia coli B and analyzed the fractions using negative-ion electrospray ionization mass spectrometry to reveal unknown lipid structures. Analysis of a fraction eluting with high salt from DEAE cellulose revealed a series of ions not corresponding to any of the known lipids of E. coli. The ions, with m/z 861.5, 875.5, 887.5, 889.5, and 915.5, were analyzed using collision-induced dissociation mass spectrometry (MS/MS) and yielded related fragmentation patterns consistent with a novel diacylated glycerophospholipid. Product ions arising by neutral loss of 216 mass units were observed with all of the unknowns. A corresponding negative product ion was also observed at m/z 215.0. Additional ions at m/z 197.0, 171.0, 146.0, and 128.0 were used to propose the novel structure phosphatidylserylglutamate (PSE). The hypothesized structure was confirmed by comparison with the MS/MS spectrum of a synthetic standard. Normal phase liquid chromatography-mass spectrometry analysis further showed that the endogenous PSE and synthetic PSE eluted with the same retention times. PSE was also observed in the equivalent anion exchange fractions of total lipids extracted from the wild-type E. coli K-12 strain MG1655.

In 1815, the British physician William Prout had advanced the theory that the molecular masses of elements were multiples of the mass of hydrogen. This "whole number rule" (and especially deviations from it) played an important role in the discussion whether elements could be mixtures of isotopes. F. Soddy's discovery (1910) that lead obtained by decay of uranium and of thorium differed in mass was considered a peculiarity of radioactive materials. The question of the existence of isotopes came up when the instruments developed by J.J. Thomson and by W. Wien to study cathode and canal rays by deflection in electric and magnetic fields were steadily improved. In 1913, Thomson mentioned a weak line at mass 22 accompanying the expected one at mass 20 when he analyzed the mass spectrum of neon. Subsequently Aston obtained the mass spectrum of chlorine with masses at 35 and 37. Still in 1921, Thomson objected heavily to the idea of isotopes. The isotope problem was finally settled, but more accurate mass measurements showed that even isotopic weights differed to some extent from the whole numbers. Based on earlier ideas of P. Langevin and J.-L. Costa, F.W. Aston and A.J. Dempster developed the idea of packing fractions and mass defects due to the transformation of a portion of the matter comprising the atomic nucleus into energy. While the determination of the exact isotopic masses had improved over the years, the accurate determination of isotopic abundances remained a problem as long as photographic recording was used. Here especially A.O. Nier pioneered using dual collectors and compensation measurements. This was the prerequisite for the discovery that isotopic ratios varied somewhat in nature. M. Dole discovered the fractionation of oxygen isotopes by photosynthesis and respiration. Today 13C/12C-ratios are employed to detect adulterations of food and in doping analysis, and 14C/13C-ratios obtained by accelerator mass spectrometry are used for dating historical objects, just to give some examples.

Radio frequency quadrupole technology: Evolution and contributions to mass spectrometry

When Goldstein's report on the "positive light" (or what is known as "Kanalstrahlen", canal rays) in gas discharge tubes first appeared in 1886, Willy Wien had just finished his thesis at the Helmholtz Institute in Berlin. Eleven years later he performed his first experiments on canal rays and found that they consisted of inert, charged and neutral particles. The charged component in canal rays could be de ected using electric and magnetic fields, enabling Wien to roughly determine their mass-to-charge ratio. Improving vacuum conditions and detection efficiency, Thomson finally resolved the lightest constituents of canal rays: the hydrogen ions H+ and H2+. This marked the beginning of mass spectrometry. The first mass spectrographs were parabola-image instruments being used by Thomson to discover isotopes. Until about 1923, canal rays became the most common ion source. Also Aston used canal rays as an ion source for the first double focussing mass spectrometer. - Wien continued his work on canal rays up to the end of his life (he died in 1928). He investigated their interaction with matter, i.e. the mean free path of canal rays in gases with respect to charge exchange and atomic excitation. His particular interest was addressed to the physics of light emission by canal rays, such as the line spectrum and the splitting of these lines in magnetic and electric fields, the Doppler effect and lifetimes.

The application of mass spectrometry to identify disease biomarkers in clinical fluids like serum using high throughput protein expression profiling continues to evolve as technology development, clinical study design, and bioinformatics improve. Previous protein expression profiling studies have offered needed insight into issues of technical reproducibility, instrument calibration, sample preparation, study design, and supervised bioinformatic data analysis. In this overview, new strategies to increase the utility of protein expression profiling for clinical biomarker assay development are discussed with an emphasis on utilizing differential lectin-based glycoprotein capture and targeted immunoassays. The carbohydrate binding specificities of different lectins offer a biological affinity approach that complements existing mass spectrometer capabilities and retains automated throughput options. Specific examples using serum samples from prostate cancer and hepatocellular carcinoma subjects are provided along with suggested experimental strategies for integration of lectin-based methods into clinical fluid expression profiling strategies. Our example workflow incorporates the necessity of early validation in biomarker discovery using an immunoaffinity-based targeted analytical approach that integrates well with upstream discovery technologies.

The discharge of electricity through gases is a subject that has had a most wonderful growth, — a growth possibly greater than that of any other single division in physics. With the discovery of cathode rays, X-rays, radioactivity, and rays of positive electricity, a new era was begun. The cathode rays were the first of the above to be brought to our attention, however, but little was known of their properties until the researches of the last decade. About fifteen years ago the wonderful X- or Roentgen rays were discovered. A few years later came that almost revolutionizing discovery of radioactivity, — revolutionizing because we are obliged to change our conceptions regarding the molecule and atom. Another of equal importance because of its bearing upon chemical composition, is afforded by J. J. Thomson's recent investigations on rays of positive electricity.

Glycerophosphoethanolamine (GPEtn) and glycerophosphoserine (GPSer) lipids were reacted with a multiplexed set of differentially isotopically enriched N-methylpiperazine acetic acid N-hydroxysuccinimide ester reagents, which place isobaric mass labels at a primary amino group. The resulting derivatized aminophospholipids were isobaric and chromatographically indistinguishable but yielded positive reporter ions (m/z 114 or 117) after collisional activation that could be used to identify and quantify individual members of the multiplex set. The chromatographic and mass spectrometric response of N-methylpiperazine amide-tagged aminophospholipids was probed using glycerophosphoethanolamine and glycerophosphoserine lipid standards. The [M+H]+ of each tagged aminophospholipid shifted 144 Da, and during collision-induced dissociation the major fragmentation ion was either m/z 114 or 117. This mode of detecting aminophospholipids was useful for an unbiased analysis of plasmalogen GPEtn lipids. Molecular species information on the esterified fatty acyl substituents was obtained by collisional activation of the [M-H]- ions. The isotope-tagged reagents were used to assess changes in the distribution of GPEtn lipids after exposure of liposomes made from phospholipids extracted from RAW 264.7 cells to Cu2+/H2O2 to illustrate the ability of these reagents to aid in the mass spectrometric identification of aminophospholipid changes that occur during biological stimuli.

An analytical procedure was evaluated for the comprehensive toxicological screening of drugs, metabolites, and pesticides in 1-mL urine samples by TurboIon spray liquid chromatography/time-of-flight mass spectrometry (LC/TOFMS) in the positive ionization mode and continuous mass measurement. The substance database consisted of exact monoisotopic masses for 637 compounds, of which an LC retention time was available for 392. A macroprogram was refined for extracting the data into a legible report, utilizing metabolic patterns and preset identification criteria. These criteria included +/-30 ppm mass tolerance, a +/-0.2-min window for absolute retention time, if available, and a minimum area count of 500. The limit of detection, determined for 90 compounds, was <0.1 mg/L for 73% of the compounds studied and >1.0 mg/L for 6% of the compounds. For method comparisons, 50 successive autopsy urine samples were analyzed by this method, and the results confirmed by gas chromatography/mass spectrometry (GC/MS). Findings for parent drugs were consistent with both methods; in addition, LC/TOFMS regularly revealed apparently correct findings for metabolites not shown by GC/MS. Mean and median mass accuracy by LC/TOFMS was 7.6 and 5.4 ppm, respectively. The procedure proved well-suited for tentative identification without reference substances. The few false positives emphasized the fact that all three parameters, exact mass, retention time, and metabolite pattern, are required for unequivocal identification.

My group focuses on several areas of biological mass spectrometry, including structural elucidation techniques, quantification, high-resolution MS and instrument development. We are also involved in metabolomics and lipidomics studies, with particular emphasis on small molecule indicators of disease and physiological status, for example, in recent years, we have become very interested in the metabolism of vitamin D. I entered the field of mass spectrometry in 1992, whilst working on my PhD research under the guidance of Karsten Levsen, a highly respected fundamental mass spectrometry researcher. During this time, I began my long interest in the application of mass spectrometry in analytical chemistry, which continues today, and will likely only end when my career does! The mass spec research was particularly refreshing back then as the early 1990s were the “wild west” of hyphenated chromatography and mass spectrometry methods and many interesting theories and ideas were developed during that time. During my PhD, I built a thermospray ionization LC/MS system, consisting of a Finnigan-MAT 4000 mass spectrometer (which was upgraded to a 4500 model) and a Vestec TSP interface. The Finnigan-MAT instrument was a single quadrupole mass spectrometer for GC/MS, which was quite dated (late 1970s!) when I was given it for my PhD research. The thermospray LC/MS system I put together was applied to the quantitative analysis of pesticides from water samples. The financial investment in this project was not without risk, as commercial electrospray instruments had started to appear on the market, fortunately (for me), then still with sub-mediocre performance. The data we obtained from the LC/TSP-MS instrument were phenomenal, however, and the analytical figures of merit still compare to today's LC/MS machines. Unfortunately, no MS/MS was possible, not even in-source CID. To obtain fragments, we had to heat the molecules in the vaporizer tube to induce thermal fragmentation. Extremely crude by today's standards, but surprisingly effective. I still enjoy the time we spent on trying to make MALDI-MS a quantitative technique for small molecules – comparable to LC/MS – in the early to mid 2000s, with excellent results. Even though we and other groups were able to demonstrate that the performance can be quite comparable to LC/MS (at much faster speeds!), MALDI-MS was never really accepted in routine laboratories, however, because of that preconception of MALDI being a non-reproducible technique. Thus, we never managed to get that idea out of peoples' heads. Fortunately, quantitative MALDI-MS research is currently undergoing a revival for application to imaging mass spectrometry. A solid understanding of the processes that control and impact quantification is vital and we will use our previous expertise to improve quantitative aspects of MALDI imaging in the future. I will give a very stereotypical answer here: you have to be persistent and never give up. While this is a textbook answer, it is nevertheless true. I think success in science usually does not require superior intelligence because many of the breakthroughs are the result of hard work and spending a lot of time in the lab. I believe scientists who take shortcuts or who are lazy will always fail eventually. On a practical note, but in the same context, an often-mentioned lab wisdom also holds true: if the mass spectrometer is running nicely, never interrupt the work and keep on running samples, even if it means staying late or until the next morning, or the entire weekend. We all know that mass spectrometers will eventually show their ugly side and break down, often for extended periods of time. I am most grateful to three individuals, who I had the pleasure of having as advisors and mentors, who were surprisingly similar in their approaches. Firstly, my PhD supervisor Karsten Levsen at the University of Hannover in Germany took a total hands-off approach to my project and he fully trusted that I could develop the project to a meaningful conclusion (which I mostly did). I then moved on to a postdoctoral position with Jon Wilkes at the National Center for Toxicological Research in Jefferson/AR in the United States, who allowed me to start an entirely independent research program in mass spectrometry and food analysis. And then, after moving to Canada, I joined Robert Boyd's group at the National Research Council in Halifax. He recently put his management style as head of department as follows (Boyd RK. From physical chemistry to mass spectrometry to government lab manager in half a century. Mass Spec Rev. 2016;35:272–310): “The most important support was the stream of talented Research Associates, Research Officers, and Postdoctoral Fellows who ended up working in the Analytical Chemistry Group. In approximate chronological order they were … , Dietrich Volmer, … “. I soon learned that with people of that quality, as their nominal ‘supervisor’ the best plan was to agree with each what they were interested in doing, then leave them to get on with it.” Nice! The single most important aspect to being successful in science is, in my opinion, to take ownership of the project that was given to you. I always considered every project I worked on (starting with the master's thesis) my personal, very own project, and the supervisor's main role was to give advice when needed (and to supply the necessary funds for the research). I am trying to use the same approach, to create independent thinkers and project managers. Obviously, the degree of support comes on a sliding scale, depending on the skills and the previous experiences of the students. The answer to this question is obviously influenced by the science I pursue. I am currently mostly excited about novel ways of ionizing molecules. The introduction of ambient ionization techniques in various shapes during the past 10 years has put the topic of ionization back into the spotlight and my group is working on unique ways of putting charge onto molecules, in particular those that won't respond to established techniques. The other area of current importance is the application of high-resolution mass spectrometry to very complex samples. This has been performed for a long time but the recent generation of affordable HRMS instruments has put the technology into the hands of many research laboratories, for example in the clinical field. I believe the future of mass spectrometry is even more exciting than 20 years ago. I sometimes hear fellow mass spectrometry scientists complain that mass spectrometry has moved away from being an independent discipline, into the routine laboratory, and that there is no room for individual science anymore. I believe the opposite is true. Fundamental mass spectrometry researchers are needed even more today, because the instruments and MS methods for the upcoming challenges in the biological sciences will not be developed in biological and medical laboratories. The future research questions will be even more challenging than today and will require novel instrumentation and methods, many of which likely do not even presently exist. Like almost every scientist, I am interested in very many things outside of science. One of those things is my interest in music reproduction. I am one of those audiophiles who still listens to vinyl, using tube amplifiers, with a stereo system that consists of so many individual components that half of my home-office space is needed to set it up. When I listen to digital music, I like it the way I like my mass spectrometers; that is, with the highest resolution possible. I would finally have the time to write the mass spectrometry textbook that I have been thinking about for at least 10 years. This would be great as I would be able to see whether students and colleagues actually like it, while I am still working in the field. Obviously, in reality this will never happen. It might be written once I retire though! None really. Perhaps Lady GaGa. Definitely Jerry Seinfeld.

Chapter 1 - HRMS: Fundamentals and Basic Concepts

Mass spectrometry in toxinology: A 21st-century technology for the study of biopolymers from venoms

Report of the 23rd Asilomar Conference on Mass Spectrometry