has_metric_category has_units has_value_concept has value type full width at half-maximum n-tuple ID based metric single run based metric chromatogram metric targeted compound peak width at half-maximum quantiles From the distribution of chromatographic peak full widths at half-maximum (FWHM) of a set of targeted/expected compounds (e.g., from a QC mix), the quantiles. For example, a value triplet represents the quartiles Q1, Q2, Q3. Only detected compounds contribute to the distribution. The compounds need to be confidently identified, ideally by several characteristics (e.g., mass spectrum and retention time). Broadening peaks across runs indicate a degrading chromatographic separation, e.g., due to column aging. MS:4000243 MS second