0:00 Mass spectrometry AKA Mass Spec is an
0:03 analytical technique that measures mass
0:06 to charge ratio in this video you will
0:08 learn how this method works and why it
0:11 is such a powerful tool in research
0:13 before we jump right into it I would
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0:20 charge but supports me a
0:24 lot scientists apply Mass spectrometry
0:28 if they opt to measure the m mass of
0:30 different molecules within a sample Mass
0:33 back helps to quantify molecules of
0:35 interest and identify them based on
0:37 their Mass quite often the technique is
0:40 used for protein analysis which makes
0:42 Mass back an important tool in the field
0:44 of proteomics but how does it work well
0:48 as for many laboratory techniques there
0:50 are different devices to accomplish Mass
0:53 back with which work all a bit
0:55 differently so be aware that some steps
0:58 shown in this video might deviate a bit
1:01 depending on the mass spectrometer and
1:03 analyzer used let's have a look at a
1:06 simplified Mass spectrometer consisting
1:09 of an iron Source an analyzer and a
1:13 detector before inserted into the mass
1:16 analyzer complex samples are often
1:19 separated for example by liquid
1:22 chromatography the first two steps in
1:25 Mass spectrometry are called desorption
1:27 and ionization and they usually occur
1:31 simultaneously this refers to the
1:33 process of transferring molecules into
1:35 the gas phase during which singly or
1:38 multiply charged ions are generated a
1:41 common method is called electrospray
1:44 ionization short ESI the sample is
1:48 passed through a capillary with an
1:50 applied electric field electrostatic
1:53 repulsion of ions and other physical
1:55 effects causes a fine aerosol that
1:58 eventually evaporates resulting in
2:00 charged gas phase ions after ionization
2:04 the ions pass through tiny slits in the
2:06 mass spectrometer and are accelerated in
2:09 a focused iron beam using an electric
2:12 field there are various analyzers in
2:14 Mass spectrometry all of which aim to
2:17 determine the mass to charge ratio of
2:20 ions one commonly used analyzer type is
2:24 the time of flight analyzer the
2:26 principle is straightforward the ions
2:28 are accelerated in an electric field
2:31 with a known voltage and ions with the
2:34 same charge gain the same kinetic energy
2:37 consquently lighter ions travel faster
2:41 through the fly tube than heavier ions
2:43 with the same
2:46 charge and more highly charged ions
2:49 travel faster compared to singly charged
2:52 ions with the same mass the time of
2:55 flight through the tube to the detector
2:57 is then measured since the the distance
3:00 is known the mass to charge ratio can be
3:03 determined the ions are also Quantified
3:07 and the mass spe result will be featured
3:09 as a chart looking like this which is
3:11 referred to as a Mass Spectrum the mass
3:14 to charge ratio is displayed on the
3:16 xaxis and the relative intensity is
3:19 shown on the Y AIS the most abundant ion
3:22 for example will be the one with the
3:24 highest peak the relative intensity is
3:26 set to 100% for that ion in this example
3:31 the iron Peaks at 24 MZ and some lower
3:35 Peaks are found with an isotopic mass of
3:38 25 and 26 MZ playing detective while
3:42 taking a look at the periodic table one
3:45 would discover that this looks pretty
3:47 much like magnesium with an atomic mass
3:50 of
3:51 24.3 U and indeed it is the smaller
3:56 Peaks are some heavier isotopes of the
3:58 element m spectrometry is usually used
4:01 for more complex molecules such as
4:04 protein samples databases help to
4:06 identify the molecules of
4:10 interest during mass spectrometry a
4:12 sample of interest is first transferred
4:15 to the gas phase and ionized which means
4:18 charge is added to the sample these
4:21 charged ions are then accelerated which
4:23 helps to separate them inside the
4:25 analyzer according to their Mass to
4:27 charge ratio a common way to accomplish
4:30 that is by measuring time it takes for
4:32 the irons to hit the detector the result
4:35 will be shown as a Mass Spectrum which
4:37 in combination with databases is used to
4:40 identify the sample of interest you want
4:43 to know how to interprete or analyze
4:45 your mass back results take a look at
4:48 this clip here if you need a break from
4:50 studying check out this video where I
4:52 explain whether and maybe even how we
4:55 could bring back dinosaurs or other
4:57 extinct species if this video could
4:59 introduce you a bit to mass spectrometry
5:02 please leave a like thanks for watching
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