Chromatography Forum

I am interested in building up a system for comprehensive LC. Has somebody experience with this technique and can give hints for the system, columns, switching valves and software?

Are you trying to comprehend HPLC?

I am interested in building up a LC x LC system - analytical scale.

Comprehensive LC doesn't mean anything, I guess you adopted the term from some papers out there that talk about comprehensive mutlidimensional HPLC.

There are several types of 2D LC's but it all depends on what you want to do (and for most applications you do not need one). I would say that the most popular is the SCX-RP configuration but before we go on you might want to share with us what is your objective (i.e. in general terms the type of application and number of analytes to be separated).

Goal is the enhancement of selectivity and sensitivity for target analytes in complex matrices, like roasted food samples.

Before you invest on building or buying an online two dimensional system, I would suggest that you try the approach with conventional instrumentation off line. For example, you can fractionate your sample with a strong cation exchange (i.e. 10 fractions), dry down, resuspend and inject in your reversed phase column. Are the results satisfactory or maybe another combination of columns is more adequate. If throughput is not a major factor you can may pull it off with an off line configuration the way I describe. If you really want to go on line after that, let us know.

Many thanks for the recommendation. The offline way we practice so far. Therefore i would ask you for a recommendation for a LC x LC system?

It seems that creativity is diverted to invent new names for old stuff. What is described here used to be called "multi-dimensional or multi-step chromatography". It used to be done by getting an appropriate switching valve (Rheodyne, Valco, . . . ), if done fully automatically with an actuating motor or air pressure system controled by the PC chrom. software. No "system" necessary.

The popularity of MD/Comprehensive LC is growing quit fast (look at the number of lectures of MD at HPLC 2008).

We (Shimadzu) have a quite nice solution for this. Ask your local sales rep for more info. We have customers that have much experience in the field of food with online 2D.

My experience with the system is that it's working nice when it's running. Just the development of methods is time consuming.

We (Dionex) offer complete solutions for various “comprehensiveâ€

Many thanks for the hardware recommadations.
What about the software for system control and data evaluation?

All components of Dionex system solutions are controlled by Chromeleon Software. Installing the system and setting up/modifying programs is easy. Chromeleon's reporting capabilities are just awesome.

Is the Chromeleon software really qualified for this special kind of data evaluatin?

Chromeleon uses excel like spread sheets for the reporting. It is therefore highly customizable to your requirements. Once established, reporting is done instantaneously, saving a lot of time.
Chromeleon is really a neat piece of software. Explaining it with a few words, however, is difficult. Best might be to see it live.

Hmm, I don't think excel sheets are not the way to go. The information you get out of it is limited and though to trace. In addition, successive cut’s never look the same. This makes the pictures somewhat screwed if you directly import into excel (and makes interpretation complicated)

For protein mapping (sxc X RP) this doesn’t matter. For complex mixtures like oils, this is somewhat more difficult.

I’m afraid that you have to wait still a few moths before dedicated software packages are released for this.