Chromatography Forum

I pose this question to students and sepsci staff.

What hasn't been done in chromatography? That is, what compounds is there no LC method for? I see tons of redundancy in the literature and
was wondering what novelty remains other than making separations
faster, cheaper, higher res, higher selectivity, etc.?

Mike

I'll bite (with some random comments!).

1. Limiting the discussion to separation techniques, LC is only one among several. Many analyses are better done by GC, CE, SFC, MS, etc.

2. In the vast majority of cases, chromatography is a tool. Compounds for which there is no method are compounds for which no one is interested in analyzing (yet).

3. Taking a concept from the classic "marketing myopia" paper (Levitt, T. (1960) "Marketing Myopia", Harvard Business Review, July- August, 1960.), LC users aren't interested in generating chromatograms, they're interested in finding out how much of their analyte(s) they have. That means that the "faster, cheaper, higher res, higher selectivity, etc." will continue. Over time, I expect that chromatographs will become more appliance-like, so that the users will be increasingly insulated from the details about what happens "under the hood".

Hello Mike,

i will have to differ on your point of view, and agree with Tom Jupille because i think that you do not look at it the right way

the goal of this field of science is to provide solutions.

we do it by understanding the physical and chemical properties of all existing compounds as best as we can in order to provide mainly the capacity for separation, detection and quantitation.

what is done with it only depends on our imagination.

the solution can be as simple has optimising an existing technic (faster, better, cheaper, simpler)
or providing innovative answers for new compounds or needs of the industry or science.

those solutions give you for example new and/or imporved pharmaceutical drugs. better understanding of proteins, better understanding of chemical reactions ect.

as i said before, we are only limited by how weird or conservative is our imagination.

I think that an area that chromatography leaves a lot to be desired is efficient separations of macromolecules (proteins, polymers etc). In addition to peak shape's I will add problems like loadability, recovery etc...

Well, I want to do some research. However, each and every idea I come across and search the literature for has been done and in most cases, done more than once. So, send me some problems so I can develop
the "solutions". Throw some novelness my way....

Now, submicron particle reverse phased stationary phase is something I'm working on but one would need one hell of a pump to make it work.

Mike

Hi Mike,

Finding an area of reasearch that nothing has been done before or finding in general what is going be the next big thing (and start working on it before everyone else) is something challenging, requiring foresee capabilities and sometimes you need to have the necessary money that will allow you to build the necessary infrastructure for your new idea(s). Furthermore, sometimes you need to have a multidisciplinary team to develop something complete and interesting to the scientific community (i.e. a winning combination of separation science + interesting biology + meaningfull data analysis/ visualization tools) -I guess that this is not a problem for universities-.

I do not want to dissapoint you but we are already working in the area of submicron particle reverse phase stattionary phases and we have the "hell of a pump(s) to make it work". Have a look in one of our last articles Shen et al. Analytical Chemistry in the ASAP session. The article's title: Ultrahigh-Throughput Proteomics using fast RPLC separations with ESI-MS/MS.

As you will see in that article, we are using 0.8 um C18 particles to achieve very high resolution, high throughput peptide separations. For example, we are able in 8 min to achieve a peak capacity of 130, and identify 700 peptides (250 proteins). The number of identifications was limited from the mass spectrometry cycle times (even if we were using an LTQ ion trap). We are using a 20000 psi pump to achieve the necessary back pressure. The silica capillary used had 50 um ID.

Having said the above, we are highly interested co-elaborating with people that have demonstrated capabilities in the field of sub-micron C18 fabrication or if they have a good/promishing idea of how to achieve better results (as with everything new, there are associated challenges).

Tom, I think that the discussion belongs on the LC forum and not under the student projects?

Agreed.

He He...

I read my post again and all I say is how difficult is to find what you are asking... not very usefull after all.

So here you are Mike:

Have a look at www.innocentive.com

This is a website that is trying to bring together companies that have an analytical, chemical or biological problems with people that want to provide "solutions". Not only that, but if you find a solution, there is a reward!! of 10000 to 100000$ depending on the difficulty of the problem and if they are asking proof of concept or not...

You can see there several analytical problems I copy paste some of them:

A method to measure protein degradation is required.
An analytical assay for lignin is required.
Ideas for an accurate, sensitive, specific and facile method for the measurement of Pyrophosphate (PPi) in cell culture samples are needed.
A method to selectively remove safrole from nutmeg oil is desired.
An analytical method to determine the purity of a complex of an aromatic acid and an aromatic amine is desired.
High-throughput format for a biological assay is needed.

etc... and there are several other added each month.

For people with more diverse background, there are problems for encapsulation, organic synthesis, biology etc.

My opinion of innocentive is that they pose difficult problems for a low price (for the US, European etc standards). However, as everyone in the world can participate, it is great money for some countries... (and that is where most of the awards go). Actually, I am working on one of their theoretical one (where they ask just to give them the concept).

Another way to find interesting problems is by trying to co-elaborate with the biologist/biochemist of your university (not an easy task always...). But in general they have some very interesting problems (and nowadays more money than the chemists).

A good person that can give feedback from this forum is Hans, who it is my understanding (from his previous posts) that he co-elaborates with biologists and he must normally now of several such analytical challenges.

Hey! I just remembered of something funny! Here is an analytical problem that my biologist/biochemist ask me all the time. "Can you please find an analytical method that separates this mixture of peptides/proteins according their abundance?" -you can not use immunoaffinity methods to do so as theoretically you do not know the high abundant ones- This is an one million dollars question!

Anyone?

Can you do ultra high-pressure fast LC separations with sub-micron particle sizes AND keep the instrument cost under 50k?

Also, Acquity can hold up to 50,000 psi with 1.3 micron particle sizes.
I'm aiming for 500 nm particle for reverse phase separations.

MS can potentially replace LC altogether but since one MS often costs more than several LCs, one can hardly justify to switch. ESI-FAIMS, depending on application, or "solution" as you call it, can do just as
well as HPLC but it often boils down to costs, ease of use, ease of
non-PhD's running it, etc.

Mike

Mike,

I used the word "solutions" from your previous post and unmgvar post, I wouldn't call it that way myself, that is why I used the quotations.

Our ultra high-pressure LC systems are home made (actually is a combination of several commercial parts) and if you are not looking to have an auto-sampler, I think that they would have cost less than50K. Ours are fully automated, and placed in a home build cart for mobility so they cost more.

About the use of MS, as you might have seen from my previous posts, I am strongly biased towards the use of MS. However, I do not think that it will be of any use to start a new debate, I think most of the people of this forum have start to having a feeling (or are already convinced) of the role that MS is playing nowadays in analytical sciences.

If you are not able to see the switch, maybe you should look where the major players (companies) that are selling LC instrumentations are investing. Waters, very early realized the role that MS would play and bought Micromass. Shimadzu, bought Kratos. Agilent, that didn't react early and didn't invest in MS had some pretty difficult couple of years. They are now trying to catch up with the introduction of several mass spectrometers and they even recently sold their semi-conductor division so they can focus more in the life science. Thermo that had several divisions, is focusing more and more in their MS division (and they are doing really well). They just bought ionanalytics a Canadian company that was developing FAIMS instrumentation.

Actually gas phase separations such as ion-mobility and FAIMS have the potential of playing a major role in the future as well... and as a matter of fact we are looking very closely at it.

Have a look at:

Shvartsburg, A. A. et al. Understanding and Designing Field Asymmetric Waveform Ion Mobility Spectrometry Separations in Gas Mixtures Anal. Chem. ; (Article); 2004; 76(24); 7366-7374.
Shvartsburg AA et al. Optimization of the design and operation of FAIMS analyzers JOURNAL OF THE AMERICAN SOCIETY FOR MASS SPECTROMETRY 16 (1): 2-12 JAN 2005
Tang K et al. High-sensitivity ion mobility spectrometry/mass spectrometry using electrodynamic ion funnel interfaces ANALYTICAL CHEMISTRY 77 (10): 3330-3339 MAY 15 2005
Tang, K.; et al. Two-Dimensional Gas-Phase Separations Coupled to Mass Spectrometry for Analysis of Complex Mixtures Anal. Chem. ; 2005; ASAP Article;

The last article describes the coupling of FAIMS-IMS-MS as we found that FAIMS and ion-mobility are providing relatively orthogonal separations.

About the ease of use, let's be realistic. Mass spectrometry was once an instrument that only high level PhD's could play with it, if you look nowadays on the job descriptions everyone is looking for BSc to do routine work on the MS or even method development. From the moment of whatever technology is adopted by a large company, it is only a matter of a couple of years (or more sometimes) until it becomes straightforward to use with the addition of the adequate software and autotune capabilities. Furthermore, if you are saying that you want to do some reseach, I do not see any problem of using research instruments.

Nano-flow chromatography was once a technology only for research laboratories and PhD's...

Hmmm... it looks like I am turning it to a debate...

PS1: When you say that Acquity can hold up to 50,000 psi, do you mean the pumps? Because the pumps spec's says 15,000 psi...
PS2: We are not commercializing our home made ultra high pressure LC systems