A solid-liquid microextraction approach from a spot in an adsorbent layer of a chromatographic plate

A new approach to extracting substances from a spot on a chromatographic plate for subsequent liquid chromatography-mass spectrometry analysis is described. This method involves extraction in a solid phase (an adsorbent layer of a chromatographic plate) - a liquid system using a simple device. For a single extraction of six selected coccidiostats from the adsorbent layer on the chromatographic plate with silica gel, 50 µL of methanol was used for 5 min. The data from the extraction experiments and liquid chromatography-mass spectrometry measurements demonstrated a good correlation between the ratio of the peak areas of the coccidiostats to the internal standard and the concentration of the substances in the range of two orders of magnitude. The coefficients of determination for the mentioned correlations range from 0.962 to 0.999. Moreover, the repeatability and reproducibility, expressed as the percentage values of relative standard deviation, do not exceed 7.5 % for any of the coccidiostats.

Some theoretical considerations on preparative separation with orthogonal pressurised planar electrochromatography

In this work, separation of multicomponent mixtures containing components with the same and different electrophoretic mobility by using orthogonal pressurised planar electrochromatography is studied theoretically. Additionally, a simple way for determination of a maximum amount of mixture causing volume overload of flat/planar columns used in this technique is presented. In the next stage, effects of change in different parameters on process performance by simulation case studies are investigated. A comparative study of separation productivity of orthogonal pressurised planar electrochromatography with the continuous and periodic modes of mixture delivery and column chromatography is carried out.

Preliminary results for interval feeding the orthogonal pressurized planar electrochromatography system with sample solution for its preparative separation

The orthogonal pressurized planar electrochromatography (OPPEC) is an example of 2-D separation technique, in which two simultaneous and orthogonal processes of electrophoresis and chromatography are involved in the separation mechanism. In the case of preparative separation of substances characterized by different electrophoretic mobility, such separation system can be constantly fed with the sample solution and the separated components can be constantly collected at its outlet. In the paper, as opposed to the previous studies, we discuss the capabilities of OPPEC technique for preparative separation of substances characterized by the same electrophoretic mobility. According to the proposed solution, the separation system can be periodically fed with the sample solution and separated components can be collected alternately at its outlet. The advantages of this new approach over the column chromatography with regard to the separation of complex mixtures have been signaled.