Orthogonal array design as a chemometric method for the optimization of analytical procedures. Part 2. Four-level design and its application in microwave dissolution of biological samples

Abstract

The theory and methodology of a four-level orthogonal array design were developed for the optimization of analytical procedures. The construction and characteristics of an OA₁₆(4⁵) matrix are described in detail, and the orthogonality of the matrix is shown by means of a third-order regression model. The response surface methodology for the OA₁₆(4⁵) matrix was then developed by using the equations obtained from the proof of orthogonality. Microwave dissolution for the determination of selenium in biological samples by hydride generation atomic absorption spectrometry was used as a practical example to demonstrate the application of the proposed four-level orthogonal array design with response surface methodology.