AssayIndex
Glossary

Terms beginning with L

9 of 238 glossary terms.

Lock mass
A reference compound infused continuously so calibration drift can be corrected in real time. Its absence limits mass accuracy to the last external calibration.
see also Mass accuracy
Label claim
The mass of compound stated on the vial. Whether it refers to gross fill or to peptide content is almost never specified.
Lactam bridge
A cyclisation through an amide bond between a side-chain carboxyl and a side-chain amine. Melanotan II and bremelanotide are lactam-cyclised.
Lyophilisation
Freeze-drying: freezing the solution then subliming the ice under vacuum. Cake structure and residual moisture are the observable outputs.
LAL
Limulus amebocyte lysate. The horseshoe-crab-derived reagent whose clotting cascade detects endotoxin. Available as gel-clot, turbidimetric and chromogenic assays.
Limits of agreement
Mean difference ± 1.96 standard deviations of the difference. The interval within which 95 % of paired differences fall.
Linearity
Proportionality of detector response to concentration across the working range. Required for an assay; irrelevant to area percent.
see also Validation · Range
Limit of detection (LOD)
The lowest amount detectable, conventionally at a signal-to-noise ratio of 3.
Limit of quantitation (LOQ)
The lowest amount quantifiable with acceptable precision, conventionally S/N ≥ 10 with RSD ≤ 10 %.