Guide for sampling and analysis of bisphenol A (BPA) in industrial effluent: chapter 7
7.1 Quality Assurance
QA consists of the policies, actions and procedures established to provide and maintain a degree of confidence in data integrity and accuracy. In order to achieve consistent data collection during a sampling event, a QA system should be followed.
7.2 Quality Control
QC is a sample or procedure intended to verify the performance characteristics of a system. The goal of QC procedures is to identify any significant change in or contamination to the sample, due to containers, handling and transportation. Typical QC components include field equipment blanks and sample spikes as discussed here.
Data quality objectives are used to establish the type and number of QC samples that must be collected. The greater the number of QC samples, the greater the degree of confidence in the reliability of results.
7.2.1 Equipment Blanks
Contamination introduced to the sample through contact with the sampling equipment is detected and measured using an equipment blank. The equipment blank must be prepared by the sample collector prior to starting a sampling event, to illustrate that no BPA is being introduced to the sample from the sampling equipment. The individual collecting the samples should use the sampling equipment to collect a sample of deionized water for BPA analysis as described in Section 5. An equipment blank should be submitted once per sampling event.
If analysis of the blanks identifies elevated concentrations of target analytes, a thorough review of the portions of the sampling plan that may be introducing contamination should be initiated, as this will affect results and corresponding conclusions.
7.2.2 Sample Spiking
It may be prudent to prepare a spiked sample with a known amount of BPA at the sample location prior to transportation of the samples if the recommended holding time cannot be met. The spiked sample should be prepared using deionized water in an appropriate BPA sample container. The sample collector should spike the deionized water with a known amount of BPA at the same time as the sample is collected. BPA standard solution can be provided by the laboratory.
If the analysis of the spiked sample has a lower BPA result than the known spiked concentration, degradation of the BPA in the sample must be evaluated. Alternative methods of shipment for the samples should be investigated, as BPA degradation will affect results and corresponding conclusions.
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