Type 20, representing the sample, contains a Region and Sample ID which acts as an identifying label for the sample. It is required only when records from these other systems are being mixed with records from this standard. See page C-5 for an example of the sequence of the record types. Since, under this standard, a file contains the results for one production run, it is necessary to define a production run in terms applicable across a wide variety of analysis types. Typically all samples in a run use the same calibration data.
Instrument conditions are typically constant throughout a run.
Results obtained on different instruments cannot be combined in one run. The time span of a production run varies with the type of analysis. Many runs for inorganic analyses take a fraction of a day. The first record in each file must be a record type 10, the Run Header. Positions 4-24 form an identifier for the run.