Sampling method and sampling device, and logD measuring method and logD measuring system

A logD measuring method of sampling a buffer solution from a liquid body comprised of two layers of liquids, an upper layer of octanol in which a predetermined chemical substance is dissolved, and a lower layer of the buffer solution in which the predetermined chemical substance is dissolved, using extracting means provided with a tubular apical end and adapted to bring the apical end from above into a liquid and to extract the liquid through the apical end, and measuring a logD of the chemical substance, the logD measuring method comprising:

• a plug injection step of injecting a plug liquid not mixing with the octanol, into the apical end of the extracting means;
• an extraction step of extracting the buffer solution by means of the extracting means with the plug liquid injected in the plug injection step;
• an in-buffer concentration measuring step of measuring a concentration of the chemical substance in the buffer solution extracted in the extraction step;
• and
• a logD calculation step of calculating the logD on the basis of the concentration measured in the in-buffer concentration measuring step.

A sampling apparatus for sampling a lower-layer liquid from a liquid body comprised of two layers of liquids, an upper-layer liquid and the lower-layer liquid, the sampling apparatus comprising:

• extracting means provided with a tubular apical end and adapted to bring the apical end from above into a liquid and to extract the liquid through the apical end;
• plug injecting means for injecting a plug liquid not mixing with the upper-layer liquid, into the apical end of the extracting means;
• and
• extraction controlling means for controlling the extracting means with the plug liquid injected by the plug injecting means, so as to extract the lower-layer liquid.

A logD measuring system for sampling a buffer solution from a liquid body comprised of two layers of liquids, an upper layer of octanol in which a predetermined chemical substance is dissolved, and a lower layer of the buffer solution in which the predetermined chemical substance is dissolved, and measuring a logD of the chemical substance, the logD measuring system comprising:

• extracting means provided with a tubular apical end and adapted to bring the apical end from above into a liquid and to extract the liquid through the apical end;
• plug injecting means for injecting a plug liquid not mixing with the octanol, into the apical end of the extracting means;
• extraction controlling means for controlling the extracting means with the plug liquid injected by the plug injecting means, so as to extract the buffer solution;
• in-buffer concentration measuring means for measuring a concentration of the chemical substance in the buffer solution extracted in the control by the extraction controlling means;
• and
• logD calculating means for calculating the logD on the basis of the concentration measured by the in-buffer concentration measuring means.