 Method 200.8 revision 5.4 by United States Environmental Protection Agency

1994, Determination of Trace Elements in Waters and Wastes by Inductively Coupled Plasma-Mass Spectrometry. Section3.2 defines calibration standards as dilutions of stock standard solutions used to relate instrument response to analyte concentration; §7.4 gives calibration-standard preparation. Official original method, not a claim about current regulatory approval.