Gone was the need for a separate GC detector, MS was now the detector. Several other advances paved the way for GC-MS to go mainstream. The first was the development of small, fast mass filters that were far superior to the TOF or magnetic sector instruments. The introduction of the quadrupole mass spectrometer made possible smaller, less expensive GC-MS. The GC-MS I first encountered was one of the first sold as a benchtop unit, though the computer required to run it effectively was a bench.
The bench contained a computer that still required manual setting of switches on the front panel to get it to boot. It had inch disk platters that could hold a whopping megabyte of data. Standardization of ionization energy meant that all MS units produce the same fingerprint for the same compound.
Libraries of mass spectra were digitized so that computer matching was possible. GC-MS systems could now automatically identify chromatographic peaks. Computer control also allowed temperature control the GC. The ability to ramp temperature shortened elution times and narrowed chromatographic peaks, improving detection. Improvements in vacuum technology were also important. Technology evolution occasionally results in extinction. The design of my old GC-MS is extinct.
The idea of hanging a quadrupole in the throat of a diffusion pump, while novel and space saving, perished as pumps improved. Turbomolecular pumps replaced cumbersome and messy diffusion pumps. Production of oil-free vacuum systems reduced contamination and maintenance, dramatically improving operability of systems.
By the time I encountered my first GC-MS, the leak valve was gone replaced by several technologies able to better preserve the temporal resolution of the chromatogram. Mine, as received, used a membrane separator that rejected the helium carrier gas, while passing organic components. The promise of capillary or wall-coated open tubular WCOT chromatographic columns prompted me to jettison packed column chromatography.
This required several modifications but provided a big payout for trace analysis. No more separator. Instead, the small flow out of the WCOT column would all go directly into the ion source. Samples would actually be split at injection port, letting only a little bit into the column.
The superior resolving power of the capillary column gave narrower, easier to detect peaks. The widespread adoption of wall-coated, open tubular or capillary columns, replacing packed columns, is another important advance. As a worldwide active company, Shimadzu is aware of his responsibility towards environment. Therefore, the economical operation is the design concept for GC Beside significant reduction in consumption of gases and electric power the GC has a quiet operation noise level and requires only little bench space.
It was the first GC fully consisting of RoHs compliant and recyclable materials. GC Plus Even excellence can be better. Further reduction of the detector noise level has been achieved by new electronics. This way sensitivity excellence of GC was further improved. Advanced diagnostic functionality and the new Advanced Flow Technology support the easy operation of the GC Plus also with challenging applications. Faster oven cooling allows an increase in efficiency due to shorter delay between the GC runs.
The robust system for routine analysis proves his value by extensive support of all GC column types. New developed pneumatics and flexible detectors allow precise working with all types of packed and capillary columns.
The low footprint , several automation features and metal housing makes it a sturdy GC for online analysis in process control even in rough environments. GC Easy, Efficient, Excellent. Many improvements and innovations made the GC a trendsetter for excellence in precision and sensitivity. In , Dr. Although the work published by Dr. Although a degree of prejudice against women in science continues today, I am reminded of the immense barriers women-scientists have overcome.
I am thankful that I am a scientist during a time when information is easily shared on a global scale, and a time when women in science are being valued and celebrated! Chromatographia, 43 , Picture copied from Bobleter, O. Professor Erika Cremer — A pioneer in gas chromatography. Chromatographia, 30 9 ,. Bobleter, O. Cremer, E. Prior Ettre, L. James, A. Holmes and Morrell are credited by some for the development of GC-MS due to the independent but near-simultaneous demonstration.
None of these four scientists patented the technology, leaving other researchers and companies free to adapt and improve on the method. Mass spectrometers work on several different principles. The LKB instrument used a magnet to disperse the ions just like Thomson did years earlier. Several other advances paved the way for GC-MS to go mainstream. The instruments became smaller and less expensive.
With developments in computing power, libraries of mass spectra could be compiled and computers could identify chromatographic peaks. GC-MS is an essential technology in modern analytical chemistry labs. The commemorative plaque reads:. In , Dow Chemical scientists Fred McLafferty and Roland Gohlke first demonstrated the combination of gas chromatography GC and mass spectrometry MS to identify individual substances in a mixture. This was the first coupling of a separation technology with a spectrometry technique to provide rapid characterization of chemical components.
GC-MS remains one of the most powerful, flexible, and widely used tools for analyzing chemical mixtures in drug screening, forensic, environmental, and trace analysis, as well as other applications. The author wishes to thank contributors to and reviewers of this booklet, all of whom helped improve its content, especially members of the ACS NHCL Subcommittee. Back to Landmarks Main Page. Learn more: About the Landmarks Program.
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Gas Chromatography-Mass Spectrometry.
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