Lower intensities of smaller tune mix ions on Qtof 6546 negative mode

Question

Hi! 
 We are using a Qtof 6546. When I try to tune it on the negative mode using the tune mix, small er tune mix ions such as 112 and 301 are a lot lower than the bigger ions even after autotunes (see below). 
 Is there any way to enhance the intensities of those ions? 
 Thank you! 
 
 Best, 
 
 Joonseok

maratabdulin · Accepted Answer

Moreover we couldn't find the way to increase the Capillary current value. It remains unchanged. And the VCap value normally should be equal to 4000 V.

maratabdulin · Answer

How do you do! Did you get any success with that trouble (low intensities of smaller ions)? We use Agilent Qtof 6530 instrument and have analogous problem and haven't fix it yet. I noticed that Capillary current on your metod editor picture is lower that it should be. We have nearly 5 microA at VCap = 4000 V. You have 2.945 mcA at VCap=3500V. On Forums they say that the problem is in Ion Transfer Capillary. We cleaned that capillary and it looks good but the problem hadn't been resolved.

maratabdulin · Answer

Excuse me - We had 5 microA at VCap=4000 V before the problem emerged.

maratabdulin · Answer

And of course, you can increase the intensities of those ions decreasing VCap value down to 1000 V or less. But in our case this couldn't help us - tuning cannot be performed because VCap value automaticaly returns to its initial value 4000 V.

Lower intensities of smaller tune mix ions on Qtof 6546 negative mode

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