What is the purpose of a field blank when collecting samples?

The purpose of a field blank is to document the validity of field samples collected during the sampling process. A field blank is essentially a sample that contains no analytes and is treated in the same manner as other samples. By including a field blank, you can ascertain whether any contamination occurred during sample collection, transportation, or analysis. If the field blank shows detectable levels of the analyte, it indicates potential contamination, which raises questions about the integrity of the field samples and their reliability for analysis.

Field blanks serve a critical role in verifying that the procedures and techniques used during the sampling process do not introduce erroneous results. They help establish a baseline measurement that is free from contamination, allowing for comparison with the actual field samples. This is essential for ensuring the quality and credibility of environmental data and research findings.