Pump precision or pump constancy We differentiate between long-term and short-term constancy a Long-term constancy One way to access this is the precision often incorrectly: Does it drip into container? These 3 locations in Victoria: Remember, old solutions are often still good solutions. Open to the public ; QD In the following, the most important HPLC activities are described in more detail, just in case you do not have a description at hand. As a result you will get a surface that contains less active silanol groups.

Conclusion If you assume organic impurities on the surface of the reversed-phase column. The remarkable thing about the new technique was the high pressure to avoid confusion we should speak about high column pressure that gave the name for this technique. You know that everything works well method plus equipment. They will stick onto rough, “dirty” surfaces. The next device is the column, the heart of the unit, where the separation takes place according to the various separation mechanisms. If you use the common 0.

When I was a small boy my grandfather impressed me by always having an answer at his fingertips, no matter what was the question I asked him.

The Solution We can distinguish three possible causes of the problem: The ,romidas also features a special chapter on the retention of ionizable components in RP-HPLC, references, data tables and check lists. Small batch-to-batch variations of commercial stationary phases are frequently observed.

Use a suitable C[S column, see below. Leji “normal” chromatogram; ri[!

stavros kromidas more practical problem solving in hplc

If the cleaning step is unsuccessful, an optician’s trick might help: If everything is OK, inject standard. How large an injection volume can you use without being penalized by noticeable band broadening? This possibility is only for isocratic separations or sometimes for high-pressure gradients damper before mixing chamber. His expert knowledge coincided with his experience so that he could describe things clearly in hhplc context.


Practical Problem Solving in HPLC – PDF Free Download

In their undissociated form, an interaction with a CIS phase is possible and the retention time is large. The Structure of the Book. Very strong metal ion-contaminated stationary phase, no elution of 2,2′ -bipyridyl possible. From to he was Managing Director of Novia GmbH, a consultant company for analytical chemistry and is an independent consultant since then. But now, let’s get going According to the operating procedure, inject samples for comparison, samples and standards in a predetermined sequence and evaluate the resulting chromatograms.

More Practical Problem Solving in HPLC: Stavros Kromidas: : Books

The three basic parameters which we stavos look at in more detail are attenuation, threshold and data acquisition rate sample rate. OJ 02 03 04 05 06 07 08 09 10 11 12 13 14 15 16 17 18 What does the name of a column material tell us?

The first sample After having prepared your equipment in the described way, you can attach the source of prepared mobile phase.

A critical limit is hours – in theory. You may use a commercial vacuum degasser, implemented in your pump delivery system. Despite your careful choice, you obtain under identical chromatographic conditions mobile phase composition, pH, temperature, etc.

More Practical Problem Solving in HPLC

To include a comma in your tag, surround the tag with double quotes. Also, differences can occur using stainless steel or PEEK capillaries.


If you are one of the users who have measured the dead volume and are on top of it, you do not have to read any further. Almost always, the problem is with the uncontrolled water content in the total system, i.

This is not only a gradient in practicaal strength but also in terms of pH and ionic strength. If the signal-to-noise ration is less than 2: Water, which is always present, albeit sometimes just in traces, is adsorbed on the silica surface, and an aqueous layer is formed.

Remove column, use end fittings to avoid drying and record the conditions in a column log book.

stavros kromidas more practical problem solving in hplc

An unacceptable dead volume is essentially caused by large-diameter connecting capillaries and most of all by defective fittings. It is also not dependent on specific configurations or system models and, therefore, more timeless moge useful for anyone.

H;lc you can remove the column, close it with end fittings to avoid drying out and store it with solvent for a longer period acetonitrile is stable for a longer period than methanol because of the hydrolysis properties of the latter.

Analysis speed, sharp peaks, therefore lower limits of detection Selectivity improvements in most cases. Objective criterion at the comparison of the packing of two columns. Open to the public ;