Figure 10 : This figure shows concepts of manual sampling - left side with afixed volume ranging from a few nano liter to some hundred nano liters, right side with capillary samplers providing micro liters to about 50 µl. As manual samplers can easily damage the stationary phase just at a most critical position, they may also cause strong systematic errors. This is true not only for quantity errors but for the falsification of the qualitative data. On the right side of the figure above parts of the stationary phase which already concentrated the stronger sorbing parts of a sample remain in the sampler capillary. The next sample solution is soaked in and extracts the residual specifically enriched substances from the sample before. Now the relative concentration of the sample substances are falsified.