has_metric_category has_units has_value_concept has value type n-tuple ID free metric single run based metric retention time metric MS2 metric MS2 quantile RT fraction The interval used for acquisition of quantiles of all MS2 events divided by retention time duration. The number of values in the tuple implies the quantile mode. The metric informs about the dynamic range of the acquisition along the chromatographic separation. For MS2 scans, the comparability of the values depends on the acquisition mode and settings to select ions for fragmentation. MS:4000185 RT-MSMS-Q2 RT-MSMS-Q1 RT-MSMS-Q4 RT-MSMS-Q3 MS fraction