Confirmatory method performance requirements

Apart from confirmatory analytical methods, quality criteria have been also defined for screening tests. Screening tests must be demonstrated as having been performed with acceptable figures of merit for accuracy, specificity, and reproducibility. Although no esoteric performance requirements are peculiar to screening tests, some particular points are especially useful in tire evaluation of screening tests. 

The analysis of VOCs in water and solid samples is complex due to the large number of compounds to be analyzed and because precaution has to be taken to provide accurate and reliable results. The use of P T-GC-MS is the most adequate for trace analysis of VOCs because limits of detection at the ng/L levels can be achieved and confirmatory analysis can be performed. Although P T is a well-established technique, several analytical parameters can be optimized to obtain high sensitivity and selectivity. Eor the specific target analytes, method optimization and quality assurance are necessary. The main drawbacks of this technique result from the fact that high purity gases are required and that the system can... 

The interpretation of the term maybe present in terms of the statistical confidence in the screening test result depends on the performance characteristics of the assay and the verification of reliable performance by a body of actual test application data. Nonetheless, the confirmation that the test substance actually is present in the sample requires independent determination. For method development purposes, screening tests should be considered a part of an analytical system for a given substance, where the complete system consists of a separate confirmatory technique to verify the initial screening result. 

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