Chromatography Forum

Hello everyone, we are actually thinking about buying a new LC -MS MS and we have a very good option , Xevo TQ-S (waters ).
As we don't have the budget for buying a GCMS MS as well, it is possible to buy the APGC interface to couple to mass detector to be able running some methods that actually are running in GC MS with EI.
But i don't know the disavantages in this interface, i am planing to run some methods like, total petroleum hydrocarbons, polyaromatic hydrocarbons, volatile organic compounds , acrylamide, chloramines, organochlorine pesticides and all the stuff for the enviromental analysis .
Is it possible anyone have the experience working with this interface, or someone know what methods could be run in APGC and what can't be run?
Thanks so much for your help

My opinion: Instruments who are doing all, are doing everything at half

Is it possible anyone have the experience working with this interface, or someone know what methods could be run in APGC and what can't be run?
Thanks so much for your help

I've played with APGC with a QToF a little bit...

Ionization is NOT EI but much softer ionization (though not as soft as electrospray )

For polar compounds compounds if you run "wet" you tend to get the [M+H]+ ion (atmospheric chemical ionization with water present)...

Under dry conditions for non polar compounds you get [M*]+ (charge transfer from nitrogen)

You can also put other things in the ionization chamber to do other kinds of chemical ionization sort of)

Sergio
APGC seems over rated for the simple reason that whatever it can analyze the LC-MS can analyze while for those compounds that the LC-MS is weak or unable to properly analyze the GC-MS will not help since it uses the same or similar (related) ionization methods.
The APGC is incompatible with library identification, its response is highly non uniform, it is less sensitive than standard EI and it will not properly analyze many of your indicated compounds such as hydrocarbons, PAHs, several of the chlorinated pesticides and many of the VOCS.
My advice is to add 10-15% to the budget for an MS of GC-MS.
Amirav

Hi Sergio,

I have several years of running APGC (I work for Waters). The compounds you mentioned will run on the APGC, as Karen01 said there are two main methods of ionisation, with water and without. Changing the conditions in the source will change the ionisation, in normal practice there is enough moisture in the gasses to ionise both types of compounds. As has also been said the ionisation is soft, similar to CI (or APCI) and will yield high abundance of molecular ion (or quasi-molecular ion). This does mean that library searching is not possible but it does mean that it is far more specific and sensitive for MS/MS analysis. The technique is reproducible and the TQ-S with APGC has been shown to be very tolerant to matrix samples. The sensitivity on the TQ-S has been show to be comparable with current magnetic sector instruments. If you want any information please drop me an email and I will send you some data. Just add @waters.com to my username.