1.3 Users of this method should state the data quality objectives prior to analysis and must document and have on file the required initial demonstration performance data described in the following sections prior to using the method for analysis. When using furnace techniques, the analyst should be cautioned as to possible chemical reactions occurring at elevated temperatures which may result in either suppression or enhancement of the analysis element (see Sec. 4.0). To ensure valid data with furnace techniques, the analyst must examine each sample for interference effects (see Sec. 9.0) and, if detected, treat them accordingly, using either successive dilution, matrix modification, or the method of standard additions (see Sec. 9.10).