Evaluation of the Uncertainty Associated to the Determination of Heavy Metals in Seawater Using Graphite Furnace Atomic Absorption Spectrometry

Abstract

This work describes the estimation of uncertainty following the “bottom‐up” and the “top‐down” approaches for the determination of several trace metals in seawater when using a classical 1‐pyrrolidinedithiocarbamate/diethyldithiocarbamate/freon extraction method followed by electrothermal atomic absorption spectrometry. A detailed analysis of the uncertainty sources of this method is included, which allows estimating the expanded uncertainties. The results show that the main contribution to the relative overall uncertainty is the extraction step. The estimation of the uncertainty components is shown to be a suitable tool for the experimental design in order to obtain a small uncertainty in the analytical result.

Keywords:

• Uncertainty
• electrothermal atomic absorption spectrometry
• bottom‐up approach
• top‐down approach
• heavy metals

Verónica Pino would like to thank the Ministerio de Educación y Ciencia for the “Juan de la Cierva” contract with the University of La Laguna. The authors sincerely thank the Servicio de Medioambiente de la Universidad de La Laguna (SEMALL) for the use of laboratory facilities and GFAAS equipment.