Biological substrates: Green alternatives in trace elemental preconcentration and speciation analysis

Biological substrates have been introduced in Analytical Chemistry to encourage the development of environment-friendly methodologies. This kind of substrates offers advantages such as low cost, very simple production and biodegradability. Moreover, they are considered highly efficient materials for extraction and separation of elemental species. The current article reviews the applications of biological substrates in elemental preconcentration and speciation analysis, with emphasis in the latest analytical methodologies developed in this field. Batch and on-line microextraction techniques, based on biological substrates are presented and discussed. The applications of immobilized biological substrates are also commented in this work. Special attention is given to the novel immobilization of these substrates on nanomaterials and nanoparticles to develop solid phase extraction techniques. A comparison of methods using biological substrates in terms of analytical performance is provided. Finally, future trends, developments and challenges related to the use of biological substrates for trace metal determination are discussed. (C) 2016 Elsevier B.V. All rights reserved.