In my recent blogs, Is it True that “GC-MS is About to Change Forever”? (link to post) and GC-Orbitrap MS: The Ultimate HRAM System for Pesticide Analysis (link to post), I have focused on the current advances in gas chromatography (GC) and the huge benefits of coupling Orbitrap technology to GC.
In this post, my focus is on the benefits of modularity in GC systems and on the importance of helium conservation (a source of concern to analytical scientists). But, first I want to share two anecdotes on the history of GC.
The first anecdote comes via the recently concluded 5th Latin American Pesticide Residues Workshop (LAPRW 2015) where Dr. John Unsworth, a well known pesticides chemist, gave an insightful lecture titled, A History of Pesticide Residue Analysis. In the lecture, he discussed a key development in GC technology which was the release of the first commercial GC system, a Model 154 Vapor Fractometer (Perkin Elmer, 1955) fitted with a thermal-conductivity detector and potentiometer recorder, and required manual injection of extracts, but it was considered revolutionary at that time.
Aldrin, dieldrin, p,p’-DDT, lindane, parathion, malathion, and Systox show suitable gas chromatographic behavior between 220′ to 280′ C. Therefore, it was concluded that this technique should be very useful as a rapid method of cleanup and separation of pesticides from vegetable extracts.
My first Gas Chromatography Experiment
The lecture reminded me of my own first experience in gas chromatography in the mid-1980s (link to published article) involving the separation of eight volatile fatty acids and lactic acid using a packed column and detection using a Flame Ionization detector connected to a computing integrator. The chromatographic run time was approximately 30 minutes.
The system did have an autosampler to avoid the need for repetitive manual injection but, just 30 years later, today’s modern systems coupled to mass spectrometers and using capillary column technology, and ever more powerful software for instrument control, method development and data processing, are so much more advanced. They are now capable of determining hundreds of analytes in just a few minutes as described in a downloadable application note, titled, Three-Fold Increase in Productivity for Pesticide Residue Analysis in Baby FoodUsing Fast Triple Quadrupole GC-MS/MS (downloadable PDF).
Recent enhancements to GC technology such as the unique flexibility and robustness of the instant connect injector and detector modularity and novel helium saving injectors and more efficient oven design for lower energy consumption offer further benefits especially with regard to reduced running costs and more sustainable operation.
Gas Chromatography Modularity Provides Unrivaled System Adaptability
Our module design means that the injector (Split/Splitless and Programmable Temperature Vaporizing both in the standard and backflush configuration ) modules and detector (Flame Ionization, Electron Capture, Thermal Conductivity, Nitrogen Phosphorous, Flame Photometric and Pulse Discharge) modules can be interchanged to quickly adapt the system configuration for different applications.
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These modules, termed Instant Connect, incorporate all relevant pneumatic hardware and electronic parts necessary for making the injector or the detector a fully self-sufficient sub-unit of the instrument and can be exchanged in just two minutes.
Instead of laboratories maintaining GC systems for the occasional need of one of a specific injector/semi- semi-selective detector combination, it is easier and more economic to store instant connect modules. Other benefits include the possibility to dedicate injector modules to different types of application to avoiding cross contamination, if, for example, analyzing pesticide residues and pesticide formulations by the same system. Read more detail in our Technical note, titled, Analytical Repeatability, Accuracy, and Robustness of Instant Connect GC Modules (downloadable PDF).
Using Nitrogen for the Injector Split Flow in Gas Chromatography
In 2013, the feared shutdown of the U.S. Federal Helium Reserve, which at the time accounted for 35% of world supplies, caused restrictions on the supply of helium and also resulted in a substantial increase in the cost of helium. Although new helium plants have since opened, notably in Qatar, helium is a finite resource so it is therefore important to try to recover and reuse helium and, when possible, to find alternative solutions.
We, at Thermo Fisher Scientific Inc., have come up with a neat solution for laboratories who may have difficulty in obtaining high-purity helium by modifying our injector to utilize a secondary gas, nitrogen, for the split flow instead of helium. However, helium is still used as the mobile phase, typically at a flow rate of around 1 mL/ minute.
The net results is that the consumption of helium is reduced substantially, such that a standard cylinder of helium may last as long as 3.5 years with continuous operation of the GC system. Read more about this innovation in this document: The ‘Noble’ Undertaking of Helium Conservation (downloadable PDF).
Do also also check out our Analytical Applications Library, and Food Community which is a growing resource that is totally dedicated to our Food and Beverage customers and features the latest on-demand webinars, videos, application notes, and more.
Learn about the latest innovative Gas Chromatography solutions.
What do you consider to be the most difficult issues you currently encounter in GC and GC-MS analysis and which developments would you like to see in the future? I would be pleased to receive your views and do let me know if you have any any questions.