dilution
/ dy-LOO-shun /
Dilution is making something weaker by adding more liquid to it — usually water or a solvent. It is exactly what happens when you stir water into a too-strong glass of squash, or top up the dishwater that has gone too soapy: the same amount of stuff is now spread through more liquid, so any given sip is milder.
In the lab, to dilute a solution is to add a known amount of solvent so the concentration drops by a known factor. Take 1 millilitre of a sample and bring it to 100 millilitres total, and you have diluted it 100-fold — the analyte molecules are unchanged in number but now swim in a hundred times the volume, so the concentration is one hundredth.
Dilution matters because instruments have a window they can read accurately: a sample that is too concentrated saturates the detector, while serial dilutions can step a sample neatly down into range. The honest caveat is bookkeeping — every dilution multiplies into the final result, so a forgotten or mis-recorded dilution factor turns a right measurement into a wrong answer by a tidy power of ten.
A juice sample reads off the top of the instrument's range, so the analyst pipettes 1 mL into a 50 mL flask and fills to the mark — a 50× dilution that brings the reading neatly back on scale.
Adding solvent lowers concentration by a known factor.
Dilution lowers concentration but never removes contamination — diluting a dirty sample dilutes the dirt too. And it has a floor: dilute too far and the analyte drops below the instrument's limit of detection, vanishing into the noise.