Chromatography Forum

Hello All-

I am in the process of purchasing a HPLC for our institution that will be utilized in an undergraduate laboratory setting. My formal training is not in area of HPLC so I'm not terribly familiar with the best "options" for this type of utility. We are considering the following vendors; Thermo, Agilent, Shiamadzu, and Dionex. I am looking for an instrument that is fairly simple yet reliable, but has the flexibility of upgrades if need be. Obviously cost is a concern so I have been comparing these specific options. The biggest price concerns are the DAD versus the variable wavelength detection and the autosampler option. Any opinions would be greatly appreciated. Thanks in advance.

Which to choose?
Quarternay vs. Binary pumps
PDA vs. Variable Wavelength Detectors
Autosampler vs. Manual Injection
Thermostatted Columns vs. ?

Automatic sample injectors are fine if you plan to run numerous samples using the same set of running conditions and just want to press a button and come back for the results. In an undergraduate lab, you may not find yourself using the same running conditions twice in a row. In fact, the process of optimizing results and controlling the variables will be educational for the students. Automatic sample injectors are wasteful of sample compared with manual valves, and it can be a pain in the neck to keep them calibrated and aligned, to make sure that the needle rinse solution is appropriate, etc. Skip it and get a manual injection valve with a selection of loading loops and syringes (which I'd recommend be fixed needle with teflon-tipped plungers).

I tend to favor binary pumps with high-pressure mixing over quaternary pumps with low-pressure mixing. 95+% of undergraduate applications can be accomplished using two solvents, and there's less dead volume in the system with high-pressure mixing.

You left out the data system--computer and software--very important in modern chromatography. Yes, data could be collected with a strip chart recorder, measured with a ruler, and transcribed into Excel on the students' tablets, and they will learn a lot, but that isn't modern practice.

If you need to save money, I would skip the column compartment first--you can do quite a bit of chromatography at room temp. Stand alone column heaters can always be added later if really needed.

I would probably go with a low pressure quaternary pump--fewer pump heads to maintain and easier to switch from run conditions to wash conditions. Probably cheaper, too.

Students will learn more of the principles if they have to use a manual injector, and you will also save a lot of money. However, it will be harder to get enough runs into a normal lab period to do data processing--learning how to create standard curves and quantify unknowns.

I also think a variable wavelength detector would be more than adequate for educational purposes.

Finally, I strongly suggest you talk to the folks who would be teaching these courses. They probably have some opinions on this matter.

It depends on what you wish to teach the undergrads. If your purpose to to teach them the principles of chromatography (eg. effect of mobile phase composition on retention time, co-eluting peaks etc etc), then I agree with the comment on manual injection.

If however, you want to get the students to perform an analytical analysis with standards, triplicate injections etc. etc, then I really think you should consider an autosampler.

Why? I work with undergrad and research students and - despite being old school and believing "manual injections are good for you" - I've started to change my tune in the last couple of years. With manual injection, the students quickly become bored out of their brains and once that happens they switch off and don't learn anything.

That may be no different to previous generations of students but I've noticed when teaching with an autosampler you can load the sample tray up, press go, and instead of teaching them how to be a reproducible injector, you can talk them through interpretation, tailing, optimization, statistics etc etc.

Just my 2 cents' worth.

Hi thalvorsen,

There are some good discussion points above. Things I would like to add are this:

1) Autosampler vs Manual: I agree that manual injections are good for teaching part of the fundamentals of HPLC and if this is what you require then certainly go down that route. However, if on the other hand you are trying to prepare your undergraduates for working within industry, then 99% of labs will use Autosamplers and so this route would offer exposure.

2) Quat vs Binary: Quat is obviously going to offer you more flexibility. Although a previous comment about dead volume in Binary pumps is true, in your case I expect that this is probably not a concern as you will be niether doing very slow or very fast flow rates.

3)PDA vs VWD: If you can afford the PDA, then I would probably go with this option. Again, to expose your undergrads to the possibilities of the real world!

Just for your information Thermo and Dionex are now one in the same.

I have attached below a link for the Ultimate 3000 range. The system range covers all the requirements you have specified as well as just as importantly, budgets (perhaps look at the Basic LC for your needs).

If you need any more information, I would suggest you contact you local sales representative who I'm sure will be more than happy to help you.

http://www.dionex.com/en-us/products/li ... 72448.html

Thanks

For undergraduate teaching, my thoughts:

quaternary pump
VWD detector
autosampler plus manual valve, can teach with manual valve. But automatic samplers are so good these days that even most QC labs have them. Especially if pharmaceutical.