AssayIndex
Chromatography

Valley

The minimum of the detector signal between two adjacent peaks. Valley height relative to the smaller peak determines whether the two can be reliably integrated separately.

Related terms

Resolution (R)
Separation between two peaks: R = 2(t₂ − t₁)/(w₁ + w₂). R = 1.5 is baseline resolution. The index requires R ≥ 1.20 to the nearest named impurity.
see also Rule AX-R12 · Valley
Shoulder
An unresolved peak appearing as an asymmetric bulge on the leading or trailing edge of a larger peak. The main source of integration ambiguity.

Where this term appears

The glossary exists to make record pages readable without a chemistry degree. Every technical term on a report resolves here.