Thank you for the video! Very helpful. At the end around 10:44 you should swap the description "do pass" and "do not pass" because like this it looks like a small window of m/z does not pass. But this is a small mistake in an otherwise very helpful video.
Yes, I will admit that the explanation is perhaps a bit too qualitative. When I posted I was expecting that there was a weakness there. However, I had a good time trying to explain this, and I am glad if this video helped you in your studies.
As far as I understand the X-dimensions switch should be shifted more to thr right and the Y-dimensions more to the left, so there is a small overlap. Flipping one of the dimensions would render the flipped one meaningless.
No, it is correct as written. There are two voltages applied, + and -. Ions that are small WILL pass the first, (so their line is high), but they stop passing at a certain point (drops to the baseline). Large m/z will NOT pass the -DC rods, so they are at baseline (do not pass) and shoot up to "do pass" for +DC. The gap in the middle is the range of m/z of ions that will pass BOTH. The lines only represent the sizes that do or not pass each step. the correct size ions would be a 3rd color, at the top I suppose. The idea is to highlight the narrow window of sizes that will work, not show a line for them.
Very helpful vedio for understanding how DCand RF is used to select ions by the four rods. The only mistakes the m/z selection of the two dimentions (X, Y) should be overlapped in order to have a narrow m/z pass through the rods. Otherwise, no ion will pass through.
hi! at 4:04 the potential should not start from 0, because the radiofrequence voltage is V* (cos freq. *t). So it should start with a positive value. is it ri ght?
Great explation..but how can a rod produce both a sinusoidal and constant potential?I also saw the electrical configuration of the genertors..but I'm used to think about than electrons flux are in movement or stationary....it is killing my mind
A DC voltage and an ac voltage are combined together. So if the DC is say +1 volt and the ac is 1 volt peak to peak it would be like the ac wave was raised 1 volt on the graph, so y=sin(X) becomes y=sin(X) + 1
Thank you for the video! Very helpful.
At the end around 10:44 you should swap the description "do pass" and "do not pass" because like this it looks like a small window of m/z does not pass.
But this is a small mistake in an otherwise very helpful video.
Yes, I will admit that the explanation is perhaps a bit too qualitative. When I posted I was expecting that there was a weakness there. However, I had a good time trying to explain this, and I am glad if this video helped you in your studies.
Thank you very much. I didn't understand the alternating voltages before this, and now I understand the mass requirements for each set of quadrupoles.
Excellent! Very informative. 👍👍
There is a mistake in the graph at 10:30. The Y edge is wrong. The label "Do pass" should be "Don't pass" and vice versa.
As far as I understand the X-dimensions switch should be shifted more to thr right and the Y-dimensions more to the left, so there is a small overlap. Flipping one of the dimensions would render the flipped one meaningless.
No, it is correct as written. There are two voltages applied, + and -. Ions that are small WILL pass the first, (so their line is high), but they stop passing at a certain point (drops to the baseline). Large m/z will NOT pass the -DC rods, so they are at baseline (do not pass) and shoot up to "do pass" for +DC. The gap in the middle is the range of m/z of ions that will pass BOTH. The lines only represent the sizes that do or not pass each step. the correct size ions would be a 3rd color, at the top I suppose. The idea is to highlight the narrow window of sizes that will work, not show a line for them.
Very nice video Dr Keller, very helpful
Thank you from all videos about quadrupole this is the best for understanding😊😊helped much
Thank you very much! Nicely explained, I finally understood.
Very helpful vedio for understanding how DCand RF is used to select ions by the four rods. The only mistakes the m/z selection of the two dimentions (X, Y) should be overlapped in order to have a narrow m/z pass through the rods. Otherwise, no ion will pass through.
hi! at 4:04 the potential should not start from 0, because the radiofrequence voltage is V* (cos freq. *t). So it should start with a positive value. is it ri
ght?
Very helpful in understanding the working principle of quadrupole.
very nice explanation for beginners.. Thank you very much
at 11:34... shouldn't the do pass lines overlap? red line fitler is barring all the molecules that green line filter is allowing and vice versa.
You are correct. There is a mistake in that graph. They should have a narrow overlap for m/z to pass.
I agree
excellent finishing diagram
A basic question: how is charge related to mass and in general how does the ion source work?
Great explation..but how can a rod produce both a sinusoidal and constant potential?I also saw the electrical configuration of the genertors..but I'm used to think about than electrons flux are in movement or stationary....it is killing my mind
A DC voltage and an ac voltage are combined together. So if the DC is say +1 volt and the ac is 1 volt peak to peak it would be like the ac wave was raised 1 volt on the graph, so y=sin(X) becomes y=sin(X) + 1
thanks!I found it very helpful and clear
The ions produced by MALDI can be analysed by TOF but not by Q, whereas ESI can be
fitted with the second one. Why?
super bien expliqué, merci
Great, thanks a lot
I don't understand a point. How do you apply a RF in DC rod?
thank you very much
IS this application of magnetic quadrupole?
Please let me know, compare the cost of icp-ms quadrupole, flight time, multicollector magnetic sector. thank
Aloha
I have Varian 820 ICP MS and have some issues. Can some one help?
i liked it
what happens to the ion after it crashes?
The charge is electrically neutralized, at which point the ion is no longer charged. It is then removed by the vacuum system.
the 5:00 explanation is a mess.
Thanks