Chromatography Forum

Dear all,
I'm working in a food safety lab. My research are dedicated to pesticides and veterinary drugs residues in foods. We already use a UPLC-MSMS (QuattroMicro) for low trace quantitation.
As a complementary tool, we wants to aquire a LC-TOF system for fast and full scan screening of samples.
After preliminary study we retained two candidates: LCT-Premier from Waters and 6210 from Agilent. I already test the LCT-Premier and I will test the 6210 next month.

Does anyone has already make a comparative study with this two systems?
Any comments from actual users of this systems will be welcome.

Thanks in advance. Best regards.

We have a GCT and a LCT from Waters and have been happy with them.

Ours are older models, but are both based on TDC type detectors. One needs to realize the limiatations of this approach when processing and acquiring data. You can see some info on my web page at the bottom of the accurate mass topic..

http://users.chartertn.net/slittle/


The JEOL system uses an ADC type detector and they contract the two type detectors in the following paper..

http://www.jeol.se/JEOL%20News/news28A/ ... index.html

I don't know which type of detector is on the Agilent LCMS system. By the dynamic range, probably ADC??

Thanks James for the response.

The LCT Premier is an TDC system while the Agilent used an ADC type detector.
If I well understand the informations on your web page, there is some limitations of using TDC system instead of ADC. Saturation of signal for higher concentration occured due to dead time shift and only one ions is counted when multiple ions arrive simultaneously at the detector.

Is the limitations of TDC system really problematic when working only with a small mass range (10-1000) which mean a faster scan speed and with small concentrations of analytes (1-500 ng/ml).

I see that Waters developed a DRE (dynamic range extend) mode to limitate the number of ions to flight. Is this solutions enough to compensate the limitations of TDC system?

Hard to say about the new instruments. Our GCT and LCT are both fairly old and don't have the new DRE technology.

The TOF instruments don't really scan, just pulse a packet of ions down the flight tube and measure the times. Thus more sensitive than a scanning instrument such as a quadrupole.

Probably should get them to run a sample with varying concentrations many times and get some statistics to compare the instruments.

I did this when evaluating the Applied Biosystems and Waters instruments. Both had some problems with precision and accuracy. I liked the Waters source and software at the time better than the Applied BIosystems instrument.

On our instrument, we get the best data when carefully manually processing the accurate mass data. Usually try to get the lockmass and ion of interest close to the same intensity.

Didn't have the same problems when doing accurate mass GCMS on a magnetic, but the magnetic was much harder to tune and operate.

The Waters TOF instruments easy to run and resolution is always good without any tuning.

Good luck, let me know how it turns out..