Plackett-Burman designs problem

Similar problems occur when examining different column factors. As already mentioned before, one is able to examine only one of the three column factors at the same time in a design (see Section 3.4.2). Suppose for example that one would like to examine the factors batch and manufacturer , among other factors, in a Plackett-Burman design and that the design for seven factors described in Table 3.16 was selected. In this design each factor has two levels, e.g. factor A (= manufacturer) has a (+) level for column K and a (-) level for column L and factor B (= batch number) has a (+) level for batch Bj and a (-) level for batch B2. This... 

Then, the particular experimental setup to prepare a set of calibration samples can be deployed following any of the procedures explained in Chapter 2 (experimental design and optimisation). We found it very useful to set a Plackett-Burman design at each level of the analyte concentration but, of course, other possibilities exist. The important point here is to obtain a sufficiently large number of calibration samples so that any (reasonable) combination of concomitants and analyte that might appear in the problem samples has been considered previously in the calibration. This is the general rule that "you should model first what you want to predict afterwards [18]. 

Problem 2.10 The Application of a Plackett-Burman Design to the Screening of Factors Influencing a Chemical Reaction... 

The examination of more than one of the non-procedure related factors (e.g. different laboratories, analysts, instruments, columns or batches of reagents, days) by Plackett-Burman and fractional factorial designs causes problems. These designs require combinations that are impossible to... 

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