5.5 Quality Control
• Initial instrument check samples must be performed as in section 5.1. Acceptance parameters are listed in SOP BRWM Hg01.
• A reagent blank must be analyzed and show no Hg contamination at or above the reporting level of the test.
• A calibration curve is generated each day samples are analyzed. A curve generally includes three calibration standards with an r2 value of 0.90 or higher.
• Continuing calibration standards must be analyzed every 10 samples and should have a result 20% true value.
• No results should be reported outside the range of the calibrants. If samples results are higher than the highest standard, either a smaller sample should be analyzed or a higher calibration standard should be analyzed and included in the calibration curve.
• Each person that analyzes samples must run an initial demonstration of capability that includes analyzing four samples with the same known concentration of Hg. Acceptable accuracy [ 30% true value] and precision [ 20% RSD] must be demonstrated. This demonstration should be repeated on an annual basis.
• A percentage of field test results should be confirmed by fixed laboratory analysis. The confirmation sample percentage should be set for each project.