Page 1 of 1
Good peak separation of pesticides by GCMS
Posted: Thu Jan 12, 2017 1:37 pm
by Louise Kehoe
I'm trying to separate a mix of organophosphorus and organochlorine pesticides and triazine herbicides. Is it possible to separate coeluters or do I need to run the standards separately. TIA
Re: Good peak separation of pesticides by GCMS
Posted: Thu Jan 12, 2017 2:17 pm
by HPLC chemist
Probably separately (better to be safe than sorry)! There is no guarantee if you use the same chromatographic conditions that they will interfere with one another (coelute).
With an LC/MS/MS you can use a 'selected ion mode' and look for P, Cl, N...but who knows?
Re: Good peak separation of pesticides by GCMS
Posted: Thu Jan 12, 2017 2:55 pm
by Louise Kehoe
T
Probably separately (better to be safe than sorry)! There is no guarantee if you use the same chromatographic conditions that they will interfere with one another (coelute).
With an LC/MS/MS you can use a 'selected ion mode' and look for P, Cl, N...but who knows?
Thanks
Re: Good peak separation of pesticides by GCMS
Posted: Thu Jan 12, 2017 3:28 pm
by HPLC chemist
Remember, the chromatographic conditions WILL be different because the LC/MS/MS uses a smaller column. This alone changes the ratio of your solute (molecule of interest) between the mobile phases and stationary phases.
Re: Good peak separation of pesticides by GCMS
Posted: Fri Jan 13, 2017 1:36 pm
by Rndirk
What exactly are you trying to do? Pesticide analysis is typically done by GC and LC - MS(/MS). Some pesticides are better on GC, others on LC and some can be done on both. The three groups you mention are nice examples: for organochlorine i'd use GC, triazines LC and organophosphorous can be done on both.
Is it possible to seperate coeluters? If i understand your question correctly => Yes: if they have a different mass/transition
Re: Good peak separation of pesticides by GCMS
Posted: Tue Jun 27, 2017 1:55 pm
by adler_LAB
The separation can be influenced by so many factors on GC.
For a good start i would contact a column producer, they usually have a few methods for pesticides on their products.
That gives you a pre setting that you can adjust or learning from it.
Re: Good peak separation of pesticides by GCMS
Posted: Fri Jun 30, 2017 2:01 pm
by mckrause
You have a MS. Why do you need to separate the compounds? Are you trying to look for isomers?
Given your mixture, and assuming that you aren't just talking about 2 or 3 total compounds, it is highly unlikely that you will be able to chromatographically resolve all of the compounds. This is why you use a MS.