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Inst.f.Chromatography

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38 macro sampling

49macro sampling 1 ml

Figure 38 : Mass sampling is possible in µ-PLC, the upper limited is not yet reached.
In figure 38 the mobile phase flasc is used to sample 1,5 ml of an red wine extract. This resulted by shaking intensively 100 ml red wine with methylen chloride. The wick contacts the 100 x 100 mm HPTLC plate in the center. a second 5 mm hole in the cover glass plate holds the flush gas tube from the aquarium pump. 2 L/min CO2 are flushed at room temperature into the virtual chamber. The 1 mm distance glasses are seen in figure 38 in the left upper corner and right side down. The concentrated enrichment circle is not ideal round because of the non symmetric flush gas flow. But after the sampling step ends - in about 10 minutes - and after a final and correctly positioned circular drying gas flush for about 3 minutes the enriched extract area is focussed by methanol exactly from the plate center as shown in figure ###. The separation of this enriched circle was complex. First a non polar run flushed about three sharp circles. After this step further runs with mobile phases of decreasing polarity in the mode of Burgers MMD (manual multi step development) resulted in many partially overlapped circles. Lots of work will be invested to succeed with acceptable results in red wine extract analyses. What we already know: enrichment and separation must be doen under CO2. The concentrated extract is highly oxygen sensitive.
Drinking water extract analyses will be the next step of the 1.5 ml sampled µ-PLC 
Many other projects are open as this 1.5 ml PLC with unexpectedly sharp substance circles is promising.
For quantitation of complete round substance circles there are several modes open: add on short after the final focusing step of known amounts of calibration samples using quantitative capillaries. If the total amount of given calibration substance is known, the length of the bow is measurable by circular multi intgration and then the grams per degree angle can be calculated. This is add on inner standard. An external standard mode is possible practically the same way but by selecting a smaller circle as the concentrate circle. Thus the same substance X shows a somewhat smaller Rp value (Rp = percent circular position based on 100 at the front circle and zero in the plate center). The to be quantitized circle has a higher Rp value. The dependence of the quantitation calibration factor from the Rp value is available by a three step repetition of the calibration runs. Practical quantitation data will be given in a later issue of this internet book.

In the figure 38 above one sees in the lower linear area flat wires. A glass plate under the HPTLC plate is electrically heated to 55 degree centigrade in order to allow mass sampling of aquatic products. It works without any damage of the HPTLC plate, the area of the concentrate is only slightly larger than the one shown in figure 38.