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Article written by Mike Haller, Quality Manager, Analytical Products Group, Inc.
Complete article from the Edition 22 APG eNewsletter
 The goal of any analysis is to measure the sample components as accurately and precisely as possible. In order to achieve this goal, the analyst must be confident that they have control of the measurement process. A measurement process that is out of control produces data that is not accurate or defensible. The key to maintaining control of the measurement process and generating accurate, defensible data is the proper use of quality control standards.
While a known true value is essential to a quality control standard, there are several other pieces of information that should be available to be considered a quality control standard. For this reason, independently prepared quality control standards purchased from an accredited provider are essential to
producing accurate, defensible data. A properly prepared and utilized quality control standard verifies the calibration and validates the unknown sample data.
The quality control sample should be independently prepared from the calibration standards and treated in exactly the same manner as the unknown samples. The quality control standard should also meet the following guidelines: Certified Value
The quality control standard should have a certified true value. This data allows the analyst to evaluate the accuracy of the analysis.
Traceable to a NIST Standard
The quality control standard should be traceable to a NIST standard, if possible. NIST traceability allows the analysis to be traceable which verifies the accuracy of the calibration and the data.
EPA Acceptance Range
The quality control standard should have an EPA acceptance range. This information provides assurance that the data generated in the analysis would be accepted by a regulatory agency.
Inter-laboratory Acceptance Range
The quality control standard should be accompanied by an inter-laboratory acceptance range. This data provides assurance that the results are comparable to the data generated by other laboratories running the same method.
If the quality control standard does not meet all of the guidelines listed above, then the analyst loses confidence in the quality control standard and therefore loses confidence in the accuracy and defensibility of the data produced in the analysis. APG's quality control standards provide you with the perfect level of documentation and confidence that cannot be achieved when you prepare the standards yourself.
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