Chromatography Forum

Get together a selection of test samples from some of the people in your institution who will be interested in using the instrument. Try to include qualitative and quantitative samples. Get the vendors to run them for you (that's why they have demo labs), and try to visit the demo labs yourself and talk to the demo chemist/play with the software (demo chemists are generally more realistic than reps). This will give you a feel for (a) what the instruments can do; (b) how helpful the vendor is; (c) how usable the software is. Also ask for references (happy customers), and do take them up: phone the references and see how enthusiastic they are, and what sorts of work they carry out with their instruments (if they love the instrument, but work totally differently to you, their opinion may be valid but not so relevant).

Be slightly careful about comparing data in a quantitative sense (sensitivities, limits of detection etc.); if you want to go that way, design your trials carefully to avoid manufacturers making modifications to show their instrument in a better light. Things like signal:noise can be calculated in different ways, and direct comparison between manufacturers is fraught with traps. In the past when I've done this, I've had to ask manufacturers to give me access to raw peak area data, unsmoothed, unmanipulated, and done my own sensitivity calculations, having also specified that I don't want them doing things like drastically widening windows for SIM - but I've also suggested that the manufacturer is free to do a second set of runs by any means they like, to demonstrate their instrument under their own favourite conditions, just in case I'm missing something valuable.

You've said that the prices of all the systems are around your budget limit. If the reps know your budget limit, then their prices always will be around that limit! Be utterly shameless. Feel free to tell them you like their instrument, but can't really accept that offer unless they can give you an extra detector, upgrade something, or whatever other bits you feel you need. The prices of LC-MS systems are very, very very flexible. I've known people go as far as "would you do buy one, get one free?" and not get laughed at. Don't trust any promises that aren't in writing (I could embarrass a certain manufacturer here). Don't trust software unless it's proven to work (yes, another global manufactuer, you know who you are. Calling a bug a "delta" doesn't make it any better. Admit when things don't work! And fix them! Yes, you know who you are!). Don't assume something's true unless it's stated to be true; reps do not lie (in my experience) but they won't tell you the whole truth about all the bad things about their instrument without much prompting.

If anyone here tells you that you absolutely must by a particular instrument, or from a particular manufacturer, ignore their advice! Very very few of us have had experience of all the manufacturers you list, and no one will have exactly your needs, background, preferences, and future plans. The right instrument for someone else is not necessarily the right instrument for you. Listen to their reasoning, but check it applies to you before you allow it to influence your decision.

Practical issue: you seem to have a lot of quotes for quadrupole instruments. A lot of your applications are quantitative work ideally suited to a triple quad, but identification of novel products is not the forté of a quad. You might like to consider ion traps too, but whatever happens, be aware that there is no one-instrument-does-everything MS (at least not within a reasonable price-range). You may have to accept that you end up with an instrument that is good at quantification, but not enough for novel natural product research. For example, one day, you will probably find yourself wanting an accurate mass instrument.

I personally haven't, but I've got friends who swear they're superb. Try it out, see what you think!