QED and Quality Control
Guidance issued by the UK Environment Agency in May 2021 confirms that the Agency will accept results from rapid measurement techniques (RMTs or on site analysis methods.) A key requirement for meeting Environment Agency compliance for on site analysis is that the method must be able to demonstrate a robust QC procedure :
• The QED uses a single surrogate on site calibrator called Scanset which it automatically checks throughout the analysis. If the Scanset fails this QC check, it will be rejected and no analysis can be carried out until an acceptable Scanset is used.
• If this concentration of target molecules in the sample is too high or too low to allow normal analysis, the QED software alerts the user and suggests a sample dilution that will bring the QED into the correct operating range.
• The QED runs multiple self diagnostic checks on initial warmup that confirms the analyser is working correctly. If deterioration in performance or a failure is detected, a message will alert the user and give the procedure to rectify the issue. Any failure with these checks stops the QED from continuing until the error is resolved.
• At any point if contamination is detected and the cleaning procedure fails to remove the contamination, the QED will not generate any more results. All components can be deep cleaned on site in a few minutes and instrument contamination is rarely a problem.
• As a final QC check the calibration procedure is repeated after all samples in the set have been analysed, or if other factors make it necessary. This gives a drift value and an OK stamp which is an on-site analysers QC and Environment Agency acceptance May 2021 Page 7 of 10 requirement for compliance.
• The QED uses on screen messages to guide an operator through the analytical process. The software also checks for unlikely data entry parameters, incorrect extract volumes or incomplete data entry. It also prevents the user from over writing previous results with new results. This level of on board guidance makes it easier to train an operator and ensure they are competent in sample preparation and analysis with the QED.
• The QED software also monitors the sample for excessive particulate/turbidity and identifies if background organics are likely to be present, all of which can affect the results.
• The QED analysis report shows the QED serial number used, the operator name, the date samples were taken, samples were extracted and the date they were analysed.
The QED readily meets the UK Environment Agency requirements for QC. It often exceeds the QC protocols used in conventional laboratories. Users can easily obtain training on this easy to use analyser which removes the need for users to be trained analysts. The actual data from the latest generation on site analysers is also as accurate as any data from an accredited laboratory method.