Definitions are written for evaluating analytical reports and catalogue documentation. Terms can have method-specific meanings, so the issuing laboratory’s procedure remains controlling.
Assay · Accuracy · Batch or lot · Chromatogram · Identity · Limit of detection · Limit of quantitation · Mass-to-charge ratio · Measurement uncertainty · Purity · Reference standard · Retention time · Selectivity · Specificity · Superseded report
Terms
Assay
A quantitative determination of how much target material is present under a defined method. Assay is not interchangeable with chromatographic purity.
Accuracy
Closeness between an accepted reference value and the value produced by the analytical procedure.
Batch or lot
A defined production grouping used to associate a sample, product configuration and analytical record.
Chromatogram
A detector response plotted against time or another separation coordinate. Peak area percentages depend on the method, detector and integration.
Identity
Evidence that the tested analyte corresponds to the stated substance. Identity does not by itself establish purity or quantity.
Limit of detection
The lowest amount that can be detected under stated conditions, which may differ from the lowest amount that can be quantified reliably.
Limit of quantitation
The lowest amount that can be quantitatively determined with suitable performance under the method.
Mass-to-charge ratio
The value reported by mass spectrometry for an ion. Interpretation must consider charge state, adducts and the expected molecular species.
Measurement uncertainty
A parameter describing dispersion of values reasonably attributable to a measured result.
Purity
A context-dependent term. Chromatographic area purity describes detector response distribution and is not automatically the same as mass fraction or peptide content.
Reference standard
A characterized material used as a comparison or calibration basis.
Retention time
The time an analyte takes to pass through a chromatographic system under defined conditions. A match can support identification but is rarely definitive alone.
Selectivity
The ability of a procedure to distinguish the analyte from other components relevant to the measurement.
Specificity
The extent to which an analyte can be assessed unequivocally in the presence of expected components.
Superseded report
A historical record replaced by a newer applicable document. It should remain traceable rather than silently disappearing.
Related resources
COA evaluation checklist · HPLC vs LC-MS · Purity vs content