Repeatability automated methods

Automated methods are more rehable and much more precise than the average manual method dependence on the technique of the individual technologist is eliminated. The relative precision, or repeatabiUty, measured by the consistency of the results of repeated analyses performed on the same sample, ranges between 1% and 5% on automated analy2ers. The accuracy of an assay, defined as the closeness of the result or of the mean of repHcate measurements to the tme or expected value (4), is also of importance in clinical medicine. 

The validation of an automated content uniformity method and an automated dissolution method based on a validated manual method can adopt a similar approach where the equivalency data can support the requirements of the other studies involved. When validating an automated method that is not based on a validated manual method, only the repeatability and reproducibility can be combined to reduce the amount of analysis to be done since the equivalency study will not be executed. 

Autoinjector—An injection device for automated methods development in which the sample loop is repeatedly filled from a large sample reservoir rather than a sample vial carousel. 

Automated methods frequently exhibit remarkable performance not only in terms of sample throughput and cost, but in relation to the quality of results, especially in relation to repeatability and reproducibility. Several systems are currently available that enable simple automation of manual gestures these include automatic titra-tors, pH-meters with a circulating cell, etc., and involve approaches that are not fundamentally different to the corresponding manual method. These techniques are not, however, described in this chapter, nor are gas and liquid chromatography and capillary electrophoresis, automated techniques, that may be present but are not routinely used in oenological laboratories. 

The earliest studies on the automation of chemical analysis in oenology by FIA were carried out by Sarris et al. (1970). However, it was only from 1974 onwards that this technique started to become widely used in routine oenological determinations with the development of reliable and repeatable analytical methods. 

A general flow chart for partly automated method development is presented in Fig. 2. From this, it is clear that the analyst repeatedly intervenes in order to evaluate intermediate results to steer the direction of development At the outset, according to the available information as well as the experience of the analyst, the chromatographic factors that are to be examined are defined and their limits are delineated. Thereafter, the HPLC system takes over the execution of the necessary experiments and/or the chromatographic runs. The analyst evaluates the runs once they have finished. The number of peaks, and their form, resolution, and sequence are important. As a result, conditions can be hypothesized that should have the highest potential for optimal separation of all of the peaks, or at least of all the relevant ones. 

Once you have your SAS data ready for transport, you need to determine a means to deliver it. There are many ways to send data, but you should strive for process simplicity and data security. To keep your data secure and to comply with 21 CFR-Part 11, you need to encrypt your data files for transport. The best encryption you can use is key exchange high-bit encryption software such as PGP, which creates essentially unbreakable files when used properly. Once your data files are encrypted, you can either send them on physical media such as CD-ROM or send them electronically with secure transmission software such as Secure File Transport Protocol (SFTP). If you need to send data to someone once, a CD-ROM is simple enough to produce. However, if you need to send the data repeatedly, then you should use a more automated electronic method of data exchange. Shell scripts and batch files can be written to automate the electronic data transfer process. 

Furthermore, iterative approaches are useful methods to construct polyhydroxy chains with 1,2- or 1,3-diol units of any length as chiral precursors for the synthesis of complex natural products [57] because automated synthesis becomes feasible. A preparation of trans-fused polytetrahydropyranes as structural unit for polycyclic ether biotoxines by repeated reaction sequences was recently named reiterative synthesis [58]. 

Many automated instruments measure enzyme activity using fixed time colorimetric methods. Some, however, can be classed as reaction rate analysers, e.g. the centrifugal analysers, and these instruments determine the reaction rate from either the initial slope of the reaction curve or from repeat measurements at fixed intervals. In both methods the slope of the line is taken to represent the activity of the enzyme. 

The experimental order of this study was also changed from the ideal randomised and blocked design. This was justified for reasons of automation where column changes needed to be minimised. As for the aspirin study the validity of this compromise depends on the fact that the repeatability of the method, over a time span such as that required for the ruggedness test, had previously been established. 

Repeatability. Repeatability expresses the precision under the same operating conditions over a short interval of time. The recommended testing for automated content uniformity, assays, degradation and impurity methods, and dissolution methods are listed in Table 5.1. 

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