determination
When a chef says they 'determined the salt content' of a sauce, they mean they actually went and found it out — measured it, not guessed. In analytical chemistry, a determination is exactly that act: the actual measurement of how much (or whether) an analyte is present in a sample. It is the doing of the analysis, the moment the question gets answered with data.
A determination is the experimental act of finding the amount, concentration, or identity of an analyte in a particular sample. Chemists speak of 'the determination of iron in spinach' or 'a chloride determination' — the analyte plus the word naming the action. A single sample may undergo several determinations, one per analyte.
It matters as the everyday unit of analytical work: methods are designed, procedures are followed, all so that a determination can be carried out and reported. The caveat is that one determination is rarely enough — because of random error, analysts usually repeat a determination several times and report an average together with a measure of scatter.
A water lab carries out a fluoride determination on a tap-water sample, repeating it three times and reporting the average: 0.82 milligrams per liter.
A determination is the act of actually measuring the analyte.
Although 'determination' often means measuring an amount, it can also mean establishing identity (a qualitative determination). Context tells you which — usually quantitative in everyday lab speech.