Validating Analytical Results

Most refineries are supported by an analytical laboratory for their day-to-day operation.  Often, off-site or third-party laboratories will also be used to carry out non-standard or one-off analyses, or when bulk analyses (for example, mineralogical analyses of drill core samples on a new mining site) would be too onerous or too expensive to carry out at the site’s analytical laboratory.

Irrespective of the laboratory, whether it is the site’s own lab or an external provider, the refinery must have confidence in the results that are reported.  The laboratory must be able to provide sufficient information regarding the appropriate operation of instruments, sample preparation and laboratory methodology used to assure the client that the reported results are fit for use. 

The laboratory should have a robust system to regularly verify the performance of the laboratory methods (including instrument operation and sample preparation).  This includes such things as:

• Regular calibration of instruments

• Routine analysis of a check sample

• Use of a control chart

• Regular service and/or maintenance checks on equipment

In addition to these processes, there are a number of other ways that a laboratory can demonstrate the appropriateness of reported results:

• Regularly (weekly or monthly) analysis of a certified reference material

• Analysing the same sample in different runs to demonstrate consistency

• Blind testing (running a known sample with a different sample name)

• Regular participation in inter-laboratory testing programs

When analytical validity is queried, records of these types of testing are invaluable to demonstrate to the client that they can have confidence in the veracity of reported results.