Statistics for forensic toxicology - analytical techniques - mass spectrometry

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This quiz has been taken 6 times
The average score is 4 of 51

Answer Stats

Hint	Answer	% Correct
what state of matter does the sample have to be in for mass spectrometry?	gas	80%
	electrospray ionisation (ESI)	40%
are they a soft or hard technique?	hard (fragments molecules)	40%
	matrix-assisted laser desorption/ionisation (MALDI)	40%
ESI	soft (does not fragment molecules)	40%
MALDI	soft (does not fragment molecules)	40%
what are the three most common ionisation sources used in mass spectrometry?	electron ionisation (EI)	20%
	m/z	20%
MALDI	the analytes are then ionised in the plume of desorbed gases	20%
	the ions must then be detected by a detector	20%
what is the mass-to-charge ratio (m/z)?	the mass of an ion/the charge of an ion	20%
what is the process of mass spectrometry?	the sample must be ionised in an ion source	20%
EI	accelerated electrons are produced by a filament	0%
	accuracy: the ratio of the measurement error to the true m/z	0%
MALDI	a laser irradiated the sample, causing desorption	0%
what is a time-of-flight (TOF) mass analyser?	an instrument that accelerates ions in an electric field	0%
ESI	applies a high voltage to a liquid to create an aerosol containing ions	0%
how do soft ionisation techniques affect data analysis?	as they add one proton to the molecule, the m/z will increase by 1	0%
ESI	at atmospheric pressure	0%
MALDI	at atmospheric pressure	0%
how do hard ionisation techniques affect data analysis?	because they fragment the molecule, it will lower the molecular weight reading	0%
what does a quadrupole mass analyser contain?	four rods that are electrically connected	0%
how do they work?	gas phase molecules interact with electrons to produce ions	0%
what is multiple reaction monitoring (MRM)?	hundreds of pairs of ions being scanned	0%
how does it work?	ions move through the mass analyser at a velocity defined by the m/z	0%
how does it work?	it amplifies the signal of the ions	0%
	linear dynamic range: the concentration range over which signal is linear	0%
what are the two types of data generated by mass spectrometry analysis?	mass chromatogram	0%
	mass range: the range of m/z that can be analysed	0%
	mass spectrum	0%
EI	molecules collide with the electrons and are ionised and fragmented	0%
what pressure can this take place in?	must be in a vacuum	0%
	one electron strikes the plate and produces up to 3 more electrons and so on	0%
how does a quadrupole mass analyser function?	oscillating electric fields are applied to the rods	0%
what are the key characteristics of mass analysers used in mass spectrometry?	resolution: the ability to distinguish two peaks of similar m/z	0%
what is the y-axis for each?	signal intensity	0%
	signal intensity/abundance	0%
how does mass relate to time of flight?	smaller ions have a faster time of flight	0%
what does this allow?	specific masses to be transmitted	0%
what is an extracted ion chromatogram (XIC)?	the chromatogram for one or more specific m/z values	0%
what is the most common type of detector used in mass spectrometry?	the electron multiplier (EM)	0%
what does varying the voltage applied to the quadrupole allow?	the entire mass range to be scanned continuously	0%
what is each used for?	the first quadrupole is used to select the mass(es) of interest (m/z selection)	0%
what is a total ion chromatogram (TIC)?	the intensity of all masses being detected at every point in the analysis	0%
	the ions are then separated in an electromagnetic field known as a mass analyser	0%
MALDI	the sample is mixed with a matrix plate	0%
	the second quadrupole is a collision cell, where ions are fragmented by collision with a gas (e.g. argon) (fragmentation)	0%
ESI	the solvent in evaporated (desolvation) using hot nitrogen gas to produce free gas-phase ions	0%
	the third quadrupole is used to scan for specific product masses of the mass of interest (m/z selection of fragments)	0%
what does a triple quadrupole (QQQ) mass analyser contain?	three quadrupoles connected in series for tandem MS analysis	0%
what is the x-axis for each?	time	0%