has_metric_category has_units has_value_concept m/z n-tuple ID free metric single run based metric MS metric m/z acquisition range The metric informs about the dynamic range of the acquisition. Based on the used MS instrument configuration, the values should be similar. Variations between measurements may arise when employing acquisition in DDA mode. MS MS:4000069 Upper and lower limit of m/z precursor values at which MSn spectra are recorded.