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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 ...
Although thousand different substances can be determined in a single gas chromatography–mass spectrometry or liquid chromatography–mass spectrometry experiment, due to the low concentration of analytes, practical measurements (see selective ion monitoring) are limited to a smaller number (10-20) of analytes.
Gas chromatography (GC) performs the same function as liquid chromatography, but it is used for volatile mixtures. In forensic chemistry, the most common GC instruments use mass spectrometry as their detector. [1] GC-MS can be used in investigations of arson, poisoning, and explosions to determine exactly what was used.
Both, the first mass analyzer and the collision cell are continuously exposed to ions from the source, in a time independent manner. [4] It is once the ions move into the third mass analyzer that time dependence becomes a factor. [4] The first quadrupole mass filter, Q1, is the primary m/z selector after the sample leaves the ionization source.
The research team suggests using gas chromatography-mass spectrometry as the most sensitive and specific testing method for identifying MDMA and its contaminants [7] but this is out of reach for users in most countries and reagent tests remain popular, often distributed by harm-reduction organisations due to their low cost and high utility when ...
One of the most widely used methods for headspace analysis is described by the United States Environmental Protection Agency (USEPA). Originally developed by the R.S. Kerr USEPA Laboratory in Ada, Oklahoma as a "high quality, defendable, and documented way to measure" methane, ethane, and ethene, [7] [8] RSKSOP-175 is a standard operating procedure (SOP) and an unofficial method employed by ...
Sample preparation for mass spectrometry is used for the optimization of a sample for analysis in a mass spectrometer (MS). Each ionization method has certain factors that must be considered for that method to be successful, such as volume, concentration , sample phase, and composition of the analyte solution.
Atmospheric pressure chemical ionization chamber cross section. Atmospheric pressure chemical ionization (APCI) is an ionization method used in mass spectrometry which utilizes gas-phase ion-molecule reactions at atmospheric pressure (10 5 Pa), [1] [2] commonly coupled with high-performance liquid chromatography (HPLC). [3]