Doehlert design for optimization of tin analysis in mussels: study case from Bizerte Lagoon

Abstract

Experimental Doehlert design was used for the determination of the optimal conditions for tin analysis in mussel samples by Atomic Absorption Spectrometry equipped with a Transversely Heated Furnace. Five factors were chosen as being able to influence analytical signal of tin. Application of Doehlert design allowed, with minimum number of experiences, the optimization of pyrolysis and atomization temperatures (1300 and 2500 °C, respectively) and also the determination of the exact quantities of permanent modifier Ir (100 µg) and chemical modifiers Pd and Mg(NO3)2 (17 µg for both modifiers) to achieve highest sensitivity. Precision of the optimized method calculated as relative standard deviation was 5.8 %. Accuracy was checked using the reference material (NIST-SRM 2977). Analytical procedure was applied to the analysis of mussel samples collected from Bizerte lagoon. Mean concentrations varied between 0.51 and 2.72 µg.g-1 (dry weight).