Wikipedia

Gas chromatography–mass spectrometry

(Redirected fromGC-MS)

Gas chromatography–mass spectrometry(GC–MS) is ananalyticalmethod that combines the features ofgas-chromatographyandmass spectrometryto identify different substances within a test sample.[1]Applications of GC–MS includedrugdetection,fireinvestigation, environmental analysis,explosivesinvestigation, food and flavor analysis, and identification of unknown samples, including that of material samples obtained from planet Mars during probe missions as early as the 1970s. GC–MS can also be used in airport security to detect substances in luggage or on human beings. Additionally, it can identifytrace elementsin materials that were previously thought to have disintegrated beyond identification. Likeliquid chromatography–mass spectrometry,it allows analysis and detection even of tiny amounts of a substance.[2]

Example of a GC–MS instrument

GC–MS has been regarded as a "gold standard"forforensicsubstance identification because it is used to perform a 100%specifictest, which positively identifies the presence of a particular substance. A nonspecific test merely indicates that any of several in a category of substances is present. Although a nonspecific test could statistically suggest the identity of the substance, this could lead tofalse positiveidentification. However, the high temperatures (300°C) used in the GC–MS injection port (and oven) can result in thermal degradation of injected molecules,[3]thus resulting in the measurement of degradation products instead of the actual molecule(s) of interest.

History

edit

The first on-line coupling of gas chromatography to a mass spectrometer was reported in the late 1950s.[4][5]An interest in coupling the methods had been suggested as early as December 1954,[6]but conventional recording techniques had too poor temporal resolution. Fortunately,time-of-flight mass spectrometrydeveloped around the same time allowed to measure spectra thousands times a second.[7]

The development of affordable andminiaturizedcomputershas helped in the simplification of the use of this instrument, as well as allowed great improvements in the amount of time it takes to analyze a sample. In 1964,Electronic Associates, Inc. (EAI),a leading U.S. supplier of analog computers, began development of a computer controlledquadrupole mass spectrometerunder the direction ofRobert E. Finnigan.[8]By 1966 Finnigan and collaborator Mike Uthe's EAI division had sold over 500 quadrupole residual gas-analyzer instruments.[8]In 1967, Finnigan left EAI to form the Finnigan Instrument Corporation along with Roger Sant, T. Z. Chou, Michael Story, Lloyd Friedman, and William Fies.[9]In early 1968, they delivered the first prototype quadrupole GC/MS instruments to Stanford and Purdue University.[8]When Finnigan Instrument Corporation was acquired by Thermo Instrument Systems (laterThermo Fisher Scientific) in 1990, it was considered "the world's leading manufacturer of mass spectrometers".[10]

Instrumentation

edit
Main articles:Gas chromatographandMass spectrometer
The insides of the GC–MS, with the column of the gas chromatograph in the oven on the right.

The GC–MS is composed of two major building blocks: thegas chromatographand themass spectrometer.The gas chromatograph utilizes a capillary column whose properties regarding molecule separation depend on the column's dimensions (length, diameter, film thickness) as well as the phase properties (e.g. 5% phenyl polysiloxane). The difference in the chemical properties between differentmoleculesin a mixture and their relative affinity for the stationary phase of the column will promote separation of the molecules as the sample travels the length of the column. The molecules are retained by the column and then elute (come off) from the column at different times (called the retention time), and this allows the mass spectrometer downstream to capture, ionize, accelerate, deflect, and detect the ionized molecules separately. The mass spectrometer does this by breaking each molecule intoionizedfragments and detecting these fragments using their mass-to-charge ratio.

GC–MS schematic

These two components, used together, allow a much finer degree of substance identification than either unit used separately. It is not possible to make an accurate identification of a particular molecule by gas chromatography or mass spectrometry alone. The mass spectrometry process normally requires a very pure sample while gas chromatography using a traditional detector (e.g.Flame ionization detector) cannot differentiate between multiple molecules that happen to take the same amount of time to travel through the column (i.e.have the same retention time), which results in two or more molecules that co-elute. Sometimes two different molecules can also have a similar pattern of ionized fragments in a mass spectrometer (mass spectrum). Combining the two processes reduces the possibility of error, as it is extremely unlikely that two different molecules will behave in the same way in both a gas chromatograph and a mass spectrometer. Therefore, when an identifying mass spectrum appears at a characteristic retention time in a GC–MS analysis, it typically increases certainty that the analyte of interest is in the sample.

Purge and trap GC–MS

edit

For the analysis ofvolatilecompounds, apurge and trap(P&T) concentrator system may be used to introduce samples. The target analytes are extracted by mixing the sample with water and purge with inert gas (e.g.Nitrogen gas) into an airtight chamber, this is known as purging orsparging.The volatile compounds move into the headspace above the water and are drawn along apressure gradient(caused by the introduction of the purge gas) out of the chamber. The volatile compounds are drawn along a heated line onto a 'trap'. The trap is a column ofadsorbentmaterial at ambient temperature that holds the compounds by returning them to the liquid phase. The trap is then heated and the sample compounds are introduced to the GC–MS column via a volatiles interface, which is a split inlet system. P&T GC–MS is particularly suited tovolatile organic compounds(VOCs) andBTEXcompounds (aromatic compounds associated with petroleum).[11]

A faster alternative is the "purge-closed loop" system. In this system the inert gas is bubbled through the water until the concentrations of organic compounds in the vapor phase are at equilibrium with concentrations in the aqueous phase. The gas phase is then analysed directly.[12]

Types of mass spectrometer detectors

edit

The most common type of mass spectrometer (MS) associated with a gas chromatograph (GC) is the quadrupole mass spectrometer, sometimes referred to by theHewlett-Packard(nowAgilent) trade name "Mass Selective Detector" (MSD). Another relatively common detector is the ion trap mass spectrometer. Additionally one may find a magnetic sector mass spectrometer, however these particular instruments are expensive and bulky and not typically found in high-throughput service laboratories. Other detectors may be encountered such as time of flight (TOF), tandem quadrupoles (MS-MS) (see below), or in the case of an ion trap MSnwhere n indicates the number mass spectrometry stages.

GC–tandem MS

edit

When a second phase of mass fragmentation is added, for example using a second quadrupole in a quadrupole instrument, it is called tandem MS (MS/MS). MS/MS can sometimes be used to quantitate low levels of target compounds in the presence of a high sample matrix background.

The first quadrupole (Q1) is connected with a collision cell (Q2) and another quadrupole (Q3). Both quadrupoles can be used in scanning or static mode, depending on the type of MS/MS analysis being performed. Types of analysis include product ion scan, precursor ion scan,selected reaction monitoring (SRM)(sometimes referred to as multiple reaction monitoring (MRM)) and neutral loss scan. For example: When Q1 is in static mode (looking at one mass only as in SIM), and Q3 is in scanning mode, one obtains a so-called product ion spectrum (also called "daughter spectrum" ). From this spectrum, one can select a prominent product ion which can be the product ion for the chosen precursor ion. The pair is called a "transition" and forms the basis for SRM. SRM is highly specific and virtually eliminates matrix background.

Ionization

edit

After the molecules travel the length of the column, pass through the transfer line and enter into the mass spectrometer they are ionized by various methods with typically only one method being used at any given time. Once the sample is fragmented it will then be detected, usually by anelectron multiplier,which essentially turns the ionized mass fragment into an electrical signal that is then detected.

The ionization technique chosen is independent of using full scan or SIM.

Block diagram for gas chromatography using electron ionization for collecting mass spectrum

Electron ionization

edit

By far the most common and perhaps standard form of ionization iselectron ionization(EI). The molecules enter into the MS (the source is a quadrupole or the ion trap itself in an ion trap MS) where they are bombarded with free electrons emitted from a filament, not unlike the filament one would find in a standard light bulb. The electrons bombard the molecules, causing the molecule to fragment in a characteristic and reproducible way. This "hard ionization" technique results in the creation of more fragments of low mass-to-charge ratio (m/z) and few, if any, molecules approaching the molecular mass unit. Hard ionization is considered by mass spectrometrists as the employ of molecular electron bombardment, whereas "soft ionization" is charge by molecular collision with an introduced gas. The molecular fragmentation pattern is dependent upon the electron energy applied to the system, typically 70 eV (electronvolts). The use of 70 eV facilitates comparison of generated spectra with library spectra using manufacturer-supplied software or software developed by the National Institute of Standards (NIST-USA). Spectral library searches employ matching algorithms such as Probability Based Matching[13]and dot-product[14]matching that are used with methods of analysis written by many method standardization agencies. Sources of libraries include NIST,[15]Wiley,[16]the AAFS,[17]and instrument manufacturers.

Cold electron ionization

edit

The "hard ionization" process ofelectron ionizationcan be softened by the cooling of the molecules before their ionization, resulting in mass spectra that are richer in information.[18][19]In this method named cold electron ionization (cold-EI) the molecules exit the GC column, mixed with added helium make up gas and expand into vacuum through a specially designed supersonic nozzle, forming a supersonic molecular beam (SMB). Collisions with the make up gas at the expanding supersonic jet reduce the internal vibrational (and rotational) energy of the analyte molecules, hence reducing the degree of fragmentation caused by the electrons during the ionization process.[18][19]Cold-EI mass spectra are characterized by an abundant molecular ion while the usual fragmentation pattern is retained, thus making cold-EI mass spectra compatible with library search identification techniques. The enhanced molecular ions increase the identification probabilities of both known and unknown compounds, amplify isomer mass spectral effects and enable the use of isotope abundance analysis for the elucidation of elemental formulas.[20]

Chemical ionization

edit
Main article:Chemical ionization

In chemical ionization (CI) a reagent gas, typicallymethaneorammoniais introduced into the mass spectrometer. Depending on the technique (positive CI or negative CI) chosen, this reagent gas will interact with the electrons and analyte and cause a 'soft' ionization of the molecule of interest. A softer ionization fragments the molecule to a lower degree than the hard ionization of EI. One of the main benefits of using chemical ionization is that a mass fragment closely corresponding to the molecular weight of the analyte of interest is produced.[21]

In positive chemical ionization (PCI) the reagent gas interacts with the target molecule, most often with a proton exchange. This produces the species in relatively high amounts.

In negative chemical ionization (NCI) the reagent gas decreases the impact of the free electrons on the target analyte. This decreased energy typically leaves the fragment in great supply.

Analysis

edit

A mass spectrometer is typically utilized in one of two ways: full scan or selective ion monitoring (SIM). The typical GC–MS instrument is capable of performing both functions either individually or concomitantly, depending on the setup of the particular instrument.

The primary goal of instrument analysis is to quantify an amount of substance. This is done by comparing the relative concentrations among the atomic masses in the generated spectrum. Two kinds of analysis are possible, comparative and original. Comparative analysis essentially compares the given spectrum to a spectrum library to see if its characteristics are present for some sample in the library. This is best performed by acomputerbecause there are a myriad of visual distortions that can take place due to variations in scale. Computers can also simultaneously correlate more data (such as the retention times identified by GC), to more accurately relate certain data. Deep learning was shown to lead to promising results in the identification of VOCs from raw GC–MS data.[22]

Another method of analysis measures the peaks in relation to one another. In this method, the tallest peak is assigned 100% of the value, and the other peaks being assigned proportionate values. All values above 3% are assigned. The total mass of the unknown compound is normally indicated by the parent peak. The value of this parent peak can be used to fit with a chemicalformulacontaining the variouselementswhich are believed to be in the compound. Theisotopepattern in the spectrum, which is unique for elements that have many natural isotopes, can also be used to identify the various elements present. Once a chemical formula has been matched to the spectrum, the molecular structure and bonding can be identified, and must be consistent with the characteristics recorded by GC–MS. Typically, this identification is done automatically by programs which come with the instrument, given a list of the elements which could be present in the sample.

A "full spectrum" analysis considers all the "peaks" within a spectrum. Conversely, selective ion monitoring (SIM) only monitors selected ions associated with a specific substance. This is done on the assumption that at a given retention time, a set ofionsis characteristic of a certain compound. This is a fast and efficient analysis, especially if the analyst has previous information about a sample or is only looking for a few specific substances. When the amount of information collected about the ions in a given gas chromatographic peak decreases, the sensitivity of the analysis increases. So, SIM analysis allows for a smaller quantity of a compound to be detected and measured, but the degree of certainty about the identity of that compound is reduced.

Full scan MS

edit

When collecting data in the full scan mode, a target range of mass fragments is determined and put into the instrument's method. An example of a typical broad range of mass fragments to monitor would bem/z50 tom/z400. The determination of what range to use is largely dictated by what one anticipates being in the sample while being cognizant of the solvent and other possible interferences. A MS should not be set to look for mass fragments too low or else one may detect air (found asm/z28 due to nitrogen), carbon dioxide (m/z44) or other possible interference. Additionally if one is to use a large scan range then sensitivity of the instrument is decreased due to performing fewer scans per second since each scan will have to detect a wide range of mass fragments.

Full scan is useful in determining unknown compounds in a sample. It provides more information than SIM when it comes to confirming or resolving compounds in a sample. During instrument method development it may be common to first analyze test solutions in full scan mode to determine the retention time and the mass fragment fingerprint before moving to a SIM instrument method.

Selective ion monitoring

edit

In selective ion monitoring (SIM) certain ion fragments are entered into the instrument method and only those mass fragments are detected by the mass spectrometer. The advantages of SIM are that the detection limit is lower since the instrument is only looking at a small number of fragments (e.g. three fragments) during each scan. More scans can take place each second. Since only a few mass fragments of interest are being monitored,matrix interferencesare typically lower. To additionally confirm the likelihood of a potentially positive result, it is relatively important to be sure that the ion ratios of the various mass fragments are comparable to a known reference standard.

Applications

edit

Environmental monitoring and cleanup

edit

GC–MS is becoming the tool of choice for tracking organic pollutants in the environment. The cost of GC–MS equipment has decreased significantly, and the reliability has increased at the same time, which has contributed to its increased adoption inenvironmental studies.

Criminal forensics

edit

GC–MS can analyze the particles from a human body in order to help link a criminal to acrime.The analysis offiredebris using GC–MS is well established, and there is even an established American Society for Testing and Materials (ASTM) standard for fire debris analysis. GCMS/MS is especially useful here as samples often contain very complex matrices, and results used in court need to be highly accurate.

Law enforcement

edit

GC–MS is increasingly used for detection of illegal narcotics, and may eventually supplant drug-sniffing dogs.[1]A simple and selective GC–MS method for detecting marijuana usage was recently developed by the Robert Koch Institute in Germany. It involves identifying an acid metabolite of tetrahydrocannabinol (THC), the active ingredient in marijuana, in urine samples by employing derivatization in the sample preparation.[23]GC–MS is also commonly used in forensic toxicology to find drugs and/or poisons in biological specimens of suspects, victims, or the deceased. In drug screening, GC–MS methods frequently utilize liquid-liquid extraction as a part of sample preparation, in which target compounds are extracted from blood plasma.[24]

Sports anti-doping analysis

edit

GC–MS is the main tool used in sports anti-doping laboratories to test athletes' urine samples for prohibited performance-enhancing drugs, for exampleanabolic steroids.[25]

Security

edit

A post–September 11 development,explosive detectionsystems have become a part of allUSairports.These systems run on a host of technologies, many of them based on GC–MS. There are only three manufacturers certified by theFAAto provide these systems,[citation needed]one of which is Thermo Detection (formerly Thermedics), which produces theEGIS,a GC–MS-based line of explosives detectors. The other two manufacturers are Barringer Technologies, now owned by Smith's Detection Systems, and Ion Track Instruments, part of General Electric Infrastructure Security Systems.

Chemical warfare agent detection

edit

As part of the post-September 11 drive towards increased capability in homeland security and public health preparedness, traditional GC–MS units with transmission quadrupole mass spectrometers, as well as those with cylindrical ion trap (CIT-MS) and toroidal ion trap (T-ITMS) mass spectrometers have been modified for field portability and near real-time detection of chemical warfare agents (CWA) such as sarin, soman, and VX.[26]These complex and large GC–MS systems have been modified and configured with resistively heated low thermal mass (LTM) gas chromatographs that reduce analysis time to less than ten percent of the time required in traditional laboratory systems.[27]Additionally, the systems are smaller, and more mobile, including units that are mounted in mobile analytical laboratories (MAL), such as those used by the United States Marine Corps Chemical and Biological Incident Response Force MAL and other similar laboratories, and systems that are hand-carried by two-person teams or individuals, much ado to the smaller mass detectors.[28]Depending on the system, the analytes can be introduced via liquid injection, desorbed from sorbent tubes through athermal desorptionprocess, or with solid-phase micro extraction (SPME).

Chemical engineering

edit

GC–MS is used for the analysis of unknown organic compound mixtures. One critical use of this technology is the use of GC–MS to determine the composition of bio-oils processed from raw biomass.[29]GC–MS is also utilized in the identification of continuous phase component in a smart material,magnetorheological (MR) fluid.[30]

Food, beverage and perfume analysis

edit

Foodsandbeveragescontain numerousaromatic compounds,some naturally present in the raw materials and some forming during processing. GC–MS is extensively used for the analysis of these compounds which includeesters,fatty acids,alcohols,aldehydes,terpenesetc. It is also used to detect and measure contaminants from spoilage oradulterationwhich may be harmful and which is often controlled by governmental agencies, for examplepesticides.

Astrochemistry

edit

Several GC–MS systems have left earth. Two were brought toMarsby theViking program.[31]Venera11 and 12 andPioneer Venusanalysed the atmosphere ofVenuswith GC–MS.[32]TheHuygens probeof theCassini–Huygensmission landed one GC–MS onSaturn's largest moon,Titan.[33]TheMSL Curiosityrover'sSample analysis at Mars (SAM)instrument contains both a gas chromatograph and quadrupole mass spectrometer that can be used in tandem as a GC–MS.[34]The material in thecomet67P/Churyumov–Gerasimenkowas analysed by theRosettamission with a chiral GC–MS in 2014.[35]

Medicine

edit

Dozens of congenital metabolic diseases also known asinborn errors of metabolism(IEM) are now detectable bynewborn screeningtests, especially the testing using gas chromatography–mass spectrometry. GC–MS can determine compounds in urine even in minor concentration. These compounds are normally not present but appear in individuals suffering with metabolic disorders. This is increasingly becoming a common way to diagnose IEM for earlier diagnosis and institution of treatment eventually leading to a better outcome. It is now possible to test a newborn for over 100 genetic metabolic disorders by a urine test at birth based on GC–MS.[citation needed]

In combination withisotopic labelingof metabolic compounds, the GC–MS is used for determiningmetabolic activity.Most applications are based on the use of13Cas the labeling and the measurement of13C-12C ratios with anisotope ratio mass spectrometer(IRMS); an MS with a detector designed to measure a few select ions and return values as ratios.

See also

edit

References

edit
  1. ^Sparkman DO, Penton Z, Kitson FG (17 May 2011).Gas Chromatography and Mass Spectrometry: A Practical Guide.Academic Press.ISBN978-0-08-092015-3.
  2. ^Jones M."Gas Chromatography-Mass Spectrometry".American Chemical Society.Retrieved19 Nov2019.
  3. ^Fang M, Ivanisevic J, Benton HP, Johnson CH, Patti GJ, Hoang LT, et al. (November 2015)."Thermal Degradation of Small Molecules: A Global Metabolomic Investigation".Analytical Chemistry.87(21): 10935–41.doi:10.1021/acs.analchem.5b03003.PMC4633772.PMID26434689.
  4. ^Holmes JC, Morrell FA (1957). "Oscillographic Mass Spectrometric Monitoring of Gas Chromatography".Applied Spectroscopy.11(2): 86–87.Bibcode:1957ApSpe..11...86H.doi:10.1366/000370257774633394.ISSN0003-7028.S2CID97838389.
  5. ^Gohlke RS (1959). "Time-of-Flight Mass Spectrometry and Gas-Liquid Partition Chromatography".Analytical Chemistry.31(4): 535–541.doi:10.1021/ac50164a024.ISSN0003-2700.
  6. ^Patton HW, Lewis JS, Kaye WI (1955). "Separation and Analysis of Gases and Volatile Liquids by Gas Chromatography".Analytical Chemistry.27(2): 170–174.doi:10.1021/ac60098a002.
  7. ^McLafferty, Fred W.(2011-07-19)."A Century of Progress in Molecular Mass Spectrometry".Annual Review of Analytical Chemistry.4(1): 1–22.doi:10.1146/annurev-anchem-061010-114018.ISSN1936-1327.PMID21351881.
  8. ^abcBrock DC (2011)."A Measure of Success".Chemical Heritage Magazine.29(1). Archived fromthe originalon 26 October 2020.Retrieved22 March2018.
  9. ^Webb-Halpern L (2008). "Detecting Success".Chemical Heritage Magazine.26(2): 31.
  10. ^"Thermo Instrument Systems Inc. History".International Directory of Company Histories(Volume 11 ed.). St. James Press. 1995. pp. 513–514.Retrieved23 January2015.
  11. ^"Optimizing the Analysis of Volatile Organic Compounds – Technical Guide" Restek Corporation, Lit. Cat. 59887A
  12. ^Wang T, Lenahan R (April 1984). "Determination of volatile halocarbons in water by purge-closed loop gas chromatography".Bulletin of Environmental Contamination and Toxicology.32(4): 429–38.doi:10.1007/BF01607519.PMID6713137.S2CID992748.
  13. ^Stauffer DB, McLafferty FW, Ellis RD, Peterson DW (1974). "Probability based matching of mass spectra. Rapid identification of specific compounds in mixtures".Organic Mass Spectrometry.9(4): 690–702.doi:10.1002/oms.1210090710.
  14. ^Stein SE, Scott DR (September 1994)."Optimization and testing of mass spectral library search algorithms for compound identification".Journal of the American Society for Mass Spectrometry.5(9): 859–66.doi:10.1016/1044-0305(94)87009-8.PMID24222034.
  15. ^Standard Reference Data.nist.gov
  16. ^Wiley's Scientific, Technical, and Medical Databases: Home.wiley.com
  17. ^Mass Spectrometry Database Committee.ualberta.ca
  18. ^abAmirav A, Gordin A, Poliak M, Fialkov AB (February 2008)."Gas chromatography-mass spectrometry with supersonic molecular beams".Journal of Mass Spectrometry.43(2): 141–63.Bibcode:2008JMSp...43..141A.doi:10.1002/jms.1380.PMID18225851.
  19. ^abSMB–MS (Supersonic GC–MS).tau.ac.il
  20. ^Alon T, Amirav A (2006). "Isotope abundance analysis methods and software for improved sample identification with supersonic gas chromatography/mass spectrometry".Rapid Communications in Mass Spectrometry.20(17): 2579–88.Bibcode:2006RCMS...20.2579A.doi:10.1002/rcm.2637.PMID16897787.
  21. ^"IGCSE Coordinated Science:Identification of Ion and Gases | University of Cambridge - KeepNotes".keepnotes.com.Retrieved2023-12-29.
  22. ^Skarysz A (July 2018)."Convolutional neural networks for automated targeted analysis of raw gas chromatography-mass spectrometry data".2018 International Joint Conference on Neural Networks (IJCNN).pp. 1–8.doi:10.1109/IJCNN.2018.8489539.ISBN978-1-5090-6014-6.S2CID52989098.
  23. ^Hübschmann HJ (22 April 2015).Handbook of GC–MS: Fundamentals and Applications(3 ed.). John Wiley & Sons, Incorporated. p. 735.ISBN9783527674336.Retrieved22 January2018.
  24. ^Hübschmann HJ (22 April 2015).Handbook of GC–MS: Fundamentals and Applications(3 ed.). John Wiley & Sons, Incorporated. p. 731.ISBN9783527674336.Retrieved22 January2018.
  25. ^Tsivou M, Kioukia-Fougia N, Lyris E, Aggelis Y, Fragkaki A, Kiousi X, et al. (2006). "An overview of the doping control analysis during the Olympic Games of 2004 in Athens, Greece".Analytica Chimica Acta.555:1–13.doi:10.1016/j.aca.2005.08.068.
  26. ^Smith PA, Lepage CJ, Lukacs M, Martin N, Shufutinsky A, Savage PB (2010). "Field-portable gas chromatography with transmission quadrupole and cylindrical ion trap mass spectrometric detection: Chromatographic retention index data and ion/molecule interactions for chemical warfare agent identification".International Journal of Mass Spectrometry.295(3): 113–118.Bibcode:2010IJMSp.295..113S.doi:10.1016/j.ijms.2010.03.001.
  27. ^Sloan KM, Mustacich RV, Eckenrode BA (2001). "Development and evaluation of a low thermal mass gas chromatograph for rapid forensic GC–MS analyses".Field Analytical Chemistry & Technology.5(6): 288–301.doi:10.1002/fact.10011.
  28. ^Patterson GE, Guymon AJ, Riter LS, Everly M, Griep-Raming J, Laughlin BC, et al. (December 2002). "Miniature cylindrical ion trap mass spectrometer".Analytical Chemistry.74(24): 6145–53.doi:10.1021/ac020494d.PMID12510732.
  29. ^Tekin K, Karagöz S, Bektaş S (2014-12-01). "A review of hydrothermal biomass processing".Renewable and Sustainable Energy Reviews.40:673–687.doi:10.1016/j.rser.2014.07.216.
  30. ^Unuh MH, Muhamad P, Waziralilah NF, Amran MH (2019)."Characterization of Vehicle Smart Fluid using Gas Chromatography-Mass Spectrometry (GCMS)"(PDF).Journal of Advanced Research in Fluid Mechanics and Thermal Sciences.55(2): 240–248.
  31. ^SEARCHING FOR LIFE ON MARS: The Development of the Viking GCMS.NASA
  32. ^Krasnopolsky VA, Parshev VA (1981). "Chemical composition of the atmosphere of Venus".Nature.292(5824): 610–613.Bibcode:1981Natur.292..610K.doi:10.1038/292610a0.S2CID4369293.
  33. ^Niemann HB, Atreya SK, Bauer SJ, Carignan GR, Demick JE, Frost RL, et al. (December 2005)."The abundances of constituents of Titan's atmosphere from the GCMS instrument on the Huygens probe"(PDF).Nature.438(7069): 779–84.Bibcode:2005Natur.438..779N.doi:10.1038/nature04122.hdl:2027.42/62703.PMID16319830.S2CID4344046.
  34. ^"MSL Science Corner: Sample Analysis at Mars (SAM)".msl-scicorner.jpl.nasa.gov.Archived fromthe originalon 2009-03-20.Retrieved2019-06-25.
  35. ^Gösmann F, Rosenbauer H, Roll R, Böhnhardt H (October 2005). "COSAC onboard Rosetta: a bioastronomy experiment for the short-period comet 67P/Churyumov-Gerasimenko".Astrobiology.5(5): 622–31.Bibcode:2005AsBio...5..622G.doi:10.1089/ast.2005.5.622.PMID16225435.

Bibliography

edit
  • Adams RP (2007).Identification of Essential Oil Components By Gas Chromatography/Mass Spectrometry.Allured Pub Corp.ISBN978-1-932633-21-4.
  • Adlard ER, Handley AJ (2001).Gas chromatographic techniques and applications.London: Sheffield Academic.ISBN978-0-8493-0521-4.
  • Barry EF, Grob RE (2004).Modern practice of gas chromatography.New York: Wiley-Interscience.ISBN978-0-471-22983-4.
  • Eiceman GA (2000). "Gas Chromatography". In Meyers RA (ed.).Encyclopedia of Analytical Chemistry: Applications, Theory, and Instrumentation.Chichester: Wiley. p. 10627.ISBN0-471-97670-9.
  • Giannelli PC, Imwinkelried EJ (1999). "Drug Identification: Gas Chromatography.".Scientific Evidence.Vol. 2. Charlottesville: Lexis Law Publishing. p. 362.ISBN0-327-04985-5.
  • McEwen CN, Kitson FG, Larsen BS (1996).Gas chromatography and mass spectrometry: a practical guide.Boston: Academic Press.ISBN978-0-12-483385-2.
  • McMaster C, McMaster MC (1998).GC/MS: a practical user's guide.New York: Wiley.ISBN978-0-471-24826-2.
  • Message GM (1984).Practical aspects of gas chromatography/mass spectrometry.New York: Wiley.ISBN978-0-471-06277-6.
  • Niessen WM (2001).Current practice of gas chromatography–mass spectrometry.New York, N.Y: Marcel Dekker.ISBN978-0-8247-0473-5.
  • Weber A, Maurer HW, Pfleger K (2007).Mass Spectral and GC Data of Drugs, Poisons, Pesticides, Pollutants and Their Metabolites.Weinheim: Wiley-VCH.ISBN978-3-527-31538-3.
edit
Retrieved from "https://en.wikipedia.org/w/index.php?title=Gas_chromatography–mass_spectrometry&oldid=1254268690"