Doehlert design experimental matrix

The Doehlert Design [6], like the Central Composite Design, allows estimating the coefficients of a model containing linear terms, interactions and quadratic terms. Table 13 reports the experimental matrix for two and three variables, and Figure 14 shows their graphical representation. 

M. Zougagh, P. C. Rudner, A. Garcia-de-Torres and J. M. Cano-Pavon, Application of Doehlert matrix and factorial designs in the optimisation of experimental variables associated with the on-line preconcentration and determination of zinc by flow injection inductively coupled plasma atomic emission spectrometry, J. Anal. At. Spectrom., 15(12), 2000, 1589-1594. 

N. Jalbani, T. G. Kazi, M. K. Jamali, M. B. Arain, H. I. Afridi, S. T. Sheerazi and R. Ansari, Application of fractional factorial design and Doehlert matrix in the optimisation of experimental variables associated with the ultrasonic-assisted acid digestion of chocolate samples for aluminium determination by atomic absorption spectrometry, J. AO AC Int., 90(6), 2007, 1682-1688. 

The optimisation of the parameters affecting Cd(II) adsorption by the adsorbent was performed with a 2 full factorial design. A Doehlert matrix was built to obtain an optimum set of experimental conditions from a quadratic model. 

S. L. C. Ferreira, A. S. Queiroz, M. S. Fernandes and D. C. Dos-Santos, Application of factorial designs and Doehlert matrix in optimisation of experimental variables associated with the preconcentration and determination of vanadium and copper in seawater by inductively coupled plasma optical emission spectrometry, Spectrochim. Acta B, 2002, 57B(12), 1939-1950. 

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