Procedures verifying critical steps

A signoff line Is provided for verifying critical steps of a procedure. 

Additional quality assurance steps or procedures to verify critical activities meet performance requirements. The steps or procedures may be temporary or permanent... 

Once a method has been developed including a quantitative collection step combined with an exhaustive extraction process, it is necessary to test the method s wider applicability. This is unfortunately a critical step (and applies to all extraction techniques) since it is impossible to know the total amount of a certain analyte present in a real-world sample. There are certain strategies that should be adopted to verify the quantitativeness of the method. The applied extraction conditions can be altered by increasing the temperature for matrices known to bind analytes hard or increase pressure for matrices known to contain bulk levels of analytes. If this improves extraction recoveries, the method is not final. Another important option is to compare SFE recoveries with recoveries obtained with conventional extraction procedures (Soxhlet) or other modern extraction techniques (PFE). If the same results are achieved, it is likely that the developed method is quantitative. It is also possible to reextract the SFE residual with another extraction method, thereby, detecting remaining analyte residues in the matrix. A third alternative is to utilize certified reference materials where... 

The STEP procedure provides investigators with a well-structured, logical, and Independently verifiable representation of the events involved in the incident. This, however, only represents the first stage in the investigation. The second stage was to identify the critical agents and events in the incident process. 

The issuance of the batch record for operational use (either in production or research) is usually a step that is not controlled to sufficient levels. Most organizations have the batch records issued by the quality unit (which is the preferred practice), but little attention is placed on the procedure. Some firms have multiple reproductions of the master production record maintained in a file for easy and quick issuance to operations. This practice can have flaws in that extra safety precautions have to be taken when the master production record is updated. Serious errors can occur if a system is not in place to verify that the current revision is utilized. It is highly recommended that copies not be maintained ahead of the time of actual issuance due to the liabilities involved in these critical documents. 

Analytical measurements should be made with properly tested and documented procedures. These procedures should utilise controls and calibration steps to minimise random and systematic errors. There are basically two types of controls (a) those used to determine whether or not an analytical procedure is in statistical control, and (b) those used to determine whether or not an analyte of interest is present in a studied population but not in a similar control population. The purpose of calibration is to minimise bias in the measurement process. Calibration or standardisation critically depends upon the quality of the chemicals in the standard solutions and the care exercised in their preparation. Another important factor is the stability of these standards once they are prepared. Calibration check standards should be freshly prepared frequently, depending on their stability (Keith, 1991). No data should be reported beyond the range of calibration of the methodology. Appropriate quality control samples and experiments must be included to verify that interferences are not present with the analytes of interest, or, if they are, that they be removed or accommodated. 

In this step, a detailed analysis of the safety critical subsystems is performed. The purpose is to verify that the system complies with good engineering practice and that it implements the safety requirements specified in Step 3. This step accounts for most of the work in the assessment procedure. 

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