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GCMS Tune Value

Posted: Mon Dec 05, 2016 6:38 am
by ucanmoruk
Hi!

I am taking quick tune on masshunter.It gives me a pdf but i can't understand it completely.

When i am analysing a tune report, what is the important parts of it or where i look first?

Here is my last tune report. Is it suitable or is there any problem?

https://1drv.ms/b/s!Agdw4_A9y4Dwb6QAKsq6XPs5uPI

Re: GCMS Tune Value

Posted: Mon Dec 05, 2016 7:17 am
by tkubowicz
Hello

In my opinion you should take GCMS training if you don't know how to analyse tune report. Don't get me wrong but this is basic stuff for routine GCMS operation.
I can write here what key tune parameters are but it is a bit pointless (in my opinion). I believe this forum is to help with exact problems, errors etc...not to teach basic things.

You will find a lot of usefull manuals for Agilent instruments/software in internet.

Regards

Tomasz Kubowicz

Re: GCMS Tune Value

Posted: Mon Dec 05, 2016 9:05 am
by ucanmoruk
Hello

In my opinion you should take GCMS training if you don't know how to analyse tune report. Don't get me wrong but this is basic stuff for routine GCMS operation.
I can write here what key tune parameters are but it is a bit pointless (in my opinion). I believe this forum is to help with exact problems, errors etc...not to teach basic things.

You will find a lot of usefull manuals for Agilent instruments/software in internet.

Regards

Tomasz Kubowicz
Hi,

You're right but before i wrote here i am looking for on the internet, or asking who can help me on this topics. When i can't find any answer then i am writing here.

About tune reports everybody says different things like water < 20 ideal or water must be <1 etc. I am asking the question here to just to be sure.

I think forums are for learning and publishing knowledge on basic stuff or top-level informations, problems etc..

In this situation I don't write here again as a unknowing Gc person. Please forgive me.

Best regards

Oguzhan E.

Re: GCMS Tune Value

Posted: Mon Dec 05, 2016 9:10 am
by tkubowicz
Hello



You didn't understand my intention...I meant that learning should be linked with practical session (using MS with different settings to know the differences betwen them) which is impossible on forum.


Regards

Tomasz Kubowicz

Re: GCMS Tune Value

Posted: Mon Dec 05, 2016 9:57 pm
by James_Ball
The tune looks ok, but seems a little biased to the lower masses. Water is at 10% but I prefer less than 5% though I have run at 10% before without problems. If the tune was biased more to the higher masses, such that 219 was about 50-70% of 69 and 502 was 3-5% of 69 then you would probably see less water also.

Otherwise it is a good tune if it satisfies your needs, which will depend on what you are analyzing and under what protocol.

Re: GCMS Tune Value

Posted: Sun Dec 11, 2016 1:14 pm
by ucanmoruk
If the tune was biased more to the higher masses, such that 219 was about 50-70% of 69 and 502 was 3-5% of 69 then you would probably see less water also..
First, thanks for your interest and reply. So how can i reduce the water ratio?

My column is changed 2 days ago. I changed liner with a new one and also septa.

Re: GCMS Tune Value

Posted: Tue Dec 13, 2016 7:41 pm
by James_Ball
With a recent column change, after the oven has cycled to the highest temperature of your method a few time, check the interface nut to see it is still tight. The vespel/graphite ferrule will shrink due to the heating cycles the first few times and may need to be re-tightened.

I would lower the Emission current just a little, to somewhere between 30 and 32, which will improve the high mass response and lower the low mass response just a little. Plus lower emission current will yield longer filament lifetime, at least a little bit. When I run volatiles analysis I normally set the Emission to 25 since I don't need that much current to ionize everything and the filament lasts longer with the water that comes through the column.