What is the Difference Between GCMS and LCMS

The key difference between GCMS and LCMS is that GCMS uses gas chromatography to separate chemicals in a sample, while LCMS uses liquid chromatography to separate chemicals in a sample.

Sorting out the different chemicals of a mixture can be easy or difficult, depending on the type of mixture or sample involved. GCMS and LCMS are two analytical techniques that are used to sort out the different chemicals in a mixture. Both techniques first separate the chemicals of the mixture through specialized chromatography and then identify them by using a mass spectrometer.

CONTENTS

1. Overview and Key Difference
2. What is GCMS 
3. What is LCMS
4. Similarities – GCMS and LCMS
5. GCMS vs LCMS in Tabular Form
6. Summary – GCMS vs LCMS

What is GCMS (Gas Chromatography-Mass Spectrometry)?

GCMS (gas chromatography-mass spectrometry) is a method used to separate chemicals in a sample by gas chromatography and then further examine and identify them by a mass spectrometer. GCMS is an analytical technique that combines the features of gas chromatography and mass spectrometry to identify different substances or chemicals within a test sample. This technique is used for samples that have thermally stable molecules. GCMS is applied in drug detection, fire investigation, environmental analysis, explosives investigation, and identification of unknown samples, including the sample materials obtained from planet Mars during the missions as early as the 1970s. It can also be used in airports to detect illegal substances in luggage or on human beings. In addition, GCMS also identifies trace elements in material that were earlier thought to have disintegrated beyond identification.

Moreover, GCMS works on the principle that a mixture will first separate into individual substances when heated, and then the heated gases are carried through a column with an inert gas such as helium. As the separated substances emerge from the column opening, they directly flow into a mass spectrometer. Thus, this facilitates the identification of individual substances. Furthermore, GCMS is regarded as the gold standard for forensic substance identification as it is used to perform a 100% specific test.

What is LCMS?

LCMS is a method used to separate chemicals in a sample by liquid chromatography and further examine and identify them by a mass spectrometer. In this technique, liquid chromatography (HPLC) separates mixtures with multiple substances, while mass spectrometry provides special information and identification of each separated substance. LCMS technology first uses HPLC (high-performance liquid chromatography) to separate out individual substances in a complex mixture. Then these substances are subjected to ionization, where the separation of ions on the basis of their mass/charge ratio takes place. Later, the separated ions are directed to a mass spectrometer, which identifies and quantifies each ion. This enables the identification of each substance in the complex mixture.

Furthermore, LCMS technology can be used to analyze biochemical, organic, and inorganic compounds normally found in complex samples of environmental and biological origin. Therefore, this technique can be applied in areas such as biotechnology, environmental monitoring, food processing, pharmaceutical, agrochemical, and cosmetic industries.

What are the Similarities Between GCMS and LCMS?

• GCMS and LCMS are two analytical techniques that are used to sort out the different chemicals of a mixture.
• Both techniques have two phases: chromatography phase and mass spectrometry phase.
• In both techniques, mass spectrometry is common.
• Both techniques are widely applied in many modern-day industries.

What is the Difference Between GCMS and LCMS?

GCMS is a method used to separate chemicals in a sample by gas chromatography and further examine and identify them using a mass spectrometer, while LCMS is a method used to separate chemicals in a sample by liquid chromatography and further examine and identify them using a mass spectrometer. Thus, this is the key difference between GCMS and LCMS. Furthermore, GCMS uses inert gas like helium to separate out substances in a complex mixture. On the other hand, LCMS uses a mobile solvent to separate out substances in a complex mixture.

The below infographic presents the differences between GCMS and LCMS in tabular form for side-by-side comparison.

Summary – GCMS vs LCMS

GCMS and LCMS are two analytical techniques to sort out the different substances of a complex mixture. GCMS separates chemicals in a sample by gas chromatography and further examines and identifies them by a mass spectrometer. LCMS separates chemicals in a sample by liquid chromatography and further examines and identifies them by a mass spectrometer. So, this is the key difference between GCMS and LCMS.

Reference:

1. “Gas Chromatography Mass Spectrometry (GCMS).” An Overview | ScienceDirect Topics.
2. “Liquid Chromatography Mass Spectrometry (LCMS).” An Overview | ScienceDirect Topics.

Image Courtesy:

1. “GCMS Block” By Ukatoemina19 – Own work (CC BY-SA 4.0) via Commons Wikimedia
2. “Liquid Chromatography Mass Spectrometer” By Cwszot | Dagui1929 | CasJu | YassineMrabet – File:Liquid chromatography tandem Mass spectrometry diagram.pngFile:Preperative_HPLC_(zh-cn).svgFile:Ions_trap_général.pngFile:Preperative_HPLC_(zh-cn).svgFile:HPLC_apparatus_(zh-cn).svg (CC0) via Commons Wikimedia