Chromatography Forum

Dear guys,

I'm in responsible to prepare a proposale for our lab regarding purchasing LC-MS system.
Initially I put the following specs.:

1- Pump: quaternary pump
2- Injector: autosampler, vails
3- Column: C18, 200mm, 4.1mm, 5um particle, 100A pore size
4- Ionization: EI or APPI
5- Mass analyser: iontrap-TOF

Our gaols are: norcotics as powder, tablets and metabolites in blood and urine

I appreciate your advices and looking for it

Are you intending it for Quantitative Analyses?

If so an Ion-Trap may not be your best option, a triple quad MS_MS may be more suitable.

However if it is for qualitative work you should be OK.

thanks JGK

Yes, quantitative is must in our tasks.
I read a letrature from agilent stated that ion trap can do both qualitative and quantitative!!

By the way which kind of gases we have to supply for ms? Argon & helium as for ICP-MS? It needs chiller like ICP-MS?

You should also consider the optimal flow rate for your detector.
ESI usually requires low flow rate (e.g. 0.2-0.5mL / min).
The optimal column to use for these flow rates is 2mm ID, 3-5um
packing material.

The optimal LC to use for that column dimension is high pressure
binary pump with low dwell volume.

Triple quad is always better than an ion-trap for quantitative work. Don't let them tell you otherwise. I would suggest looking at the Sciex API-4000 or Waters Acquity TQD. As for the LC, you want something that is optimized for low flow rates and can work with your MS.

Generally you just need nitrogen and/or Argon depending on the mass spectrometer and manufacturer.

How much of your work will be structural determination and how much of it quantitation? Not a lot of companies offering hybrid ion traps-time of flights... I wonder how you came with that decision in the first place (i.e. what was the reasoning)?

Dear Che; this is very interesting for me and I would like to see if I am wrong.
You want the Trap fro quantificacion and the Tof, for identification??
The people use to think that this way can do scans; but as far I know at the end you detect after the Tof; and the Ions goes into the tof as packages; you can select ions using Traps or Quads; but all the ions going to reach the detector as ion pack; so base on what I believe to know how a trap-Tof system can be better better than a Q-Tof system or viceversa? at the end lineality It would'nt be affected for The Tof even if you are working Quantitative or qualitative?

Regards.

Oscar

thanks JGK

Yes, quantitative is must in our tasks.
I read a letrature from agilent stated that ion trap can do both qualitative and quantitative!!

By the way which kind of gases we have to supply for ms? Argon & helium as for ICP-MS? It needs chiller like ICP-MS?

I've worked with the API-4000 which needs air and Nitrogen supplies. From others iv'e spoken to who use this instrument (quantitative Bioanalysis) the favored front end front (LC) part is the waters UPLC or the CTC system. However the water UPLC only has a binary pump.

Che, what you are aiming to do is a fairly standard thing. All manufacturers should be able to advise on this equipment, and supply something suitable. They all make triple quads of one description or another. They should also be able to carry out this sort of analysis in their demo labs, and give you real data to prove their instrument works.

You should make up some real samples, and get the manufacturers to trial them for you, preferably with you in the lab to see how the machine works, and talk to the demo chemist.

There will be a lot of people who tell you that this or that instrument is the best, and some who will tell you the work is impossible without their favourite instrument. In the end, you need an instrument with which you are happy, and if you go for one that you have seen do the job during demonstrations, then you have positive evidence that it is a good purchase, even before you've bought it.

Good luck

thank you very much all guys.

I will change my direction of search towards three manufactrure we prefere to deal with: Agilent, AB & waters.

I need a one set of LC/MS that can done my job: identifying and quantifying drugs (heroin, cannabis, amfetamine, mdma, etc) as solid material and in boiligical samples blood & urine

Defenitely, Triple quadripole better than Ion Trap for your application.

Regards

U might want to have a look at thermo too. They do have some intresting triple quad offerings.

I find your post somewhat curious. You say that you are looking for an LC/MS system and the two ionization techniques you mention (EI and APPI) are not the most common techniques used for LC/MS. EI is the abbreviation for electron ionization and APPI is the abbreviation for atmospheric pressure photoionization. Did you mean ESI (electrospray ionization) and APCI (atmospheric chemical ionization)?

You say that you are looking for an iontrap [sic] -TOF instrument. As far as I know, there is only one manufacturer of a 3D QIT-TOF instrument and that is Shimadzu. Also, as far as I known, that instrument is only available with an electrospray ionization interface.

All the other post asking you what you want to do with this instrument are very important. I can see that you have little or no experience with these types of analyses. I would recommend that you take a course like the one my colleague and I teach for LC Resources. We are offering a session in San Diego the first week in December. Check the LC Recourses Web site (http://www.LCResources.com) for the details.

Hitachi has also one...

In my opinion you should buy ABI's 3200 Trap or 4000 Trap as these both hybrid systems will give you both qualitative and quantitative applications in one run. Since Trap resolution is 4000 and you can use for qualitative full scan functions and by using QQQ you can quantitate your samples as well.

I strongly suggest you to look at ABI's trap systems and I am confident it will definitely serve your purpose