Skip to main content
Topic: Basic questions (Read 290 times) previous topic - next topic

Basic questions

Dear community,

I have two basic questions and I would like your opinion.

1. I have a Qtof from Agilent (6538). In the parameters of the auto MS MS, it is possible to make an acquisition in ddms2 top 20.
However in publications I often see people doing the top 3. Is it a standard ?
Is it due to the machine's ability to do this?
by making the top 20 is it possible to take an M + 1 and to fragment it and to make possible bad identification?

2. I also have questions about solvents.
Is it possible that by putting ammonium acetate certain families of lipids are less detectable than by putting ammonium formate? especially MGDG and DGDG ?

Thank you in advance for your time spent answering these basic questions.

Sebas

Re: Basic questions

Reply #1
Hi

1. I have a Qtof from Agilent (6538). In the parameters of the auto MS MS, it is possible to make an acquisition in ddms2 top 20.
I have no experience about Agilent 6538, but of course, it depends on the machine spec. The trade off of scan speed and accumulation time should be identified experimentally by using standard compounds or standard materials such as NIST SRM 1950 plasma.

2. Is it possible that by putting ammonium acetate certain families of lipids are less detectable than by putting ammonium formate? especially MGDG and DGDG ?
I think, ammonium acetate is better for the sensitivity of free fatty acids. At least according to my experience, the detection rate of MGDG and DGDG is not so much different between the solvents.

Thanks,

Hiroshi