What is with that paper? – assessment of paper-based solution sampling coupled with heavy metal potentiometric sensors

Description:
In direct applications of ion-selective electrodes in samples containing high content of solids/impurities with a reduced amount of analyte, sample collection within an adsorptive substrate prior to ion measurement appears to be a necessary step. Therefore, various paper materials have been studied as substrates for solution sampling and analyte delivery system when coupled with ion-selective electrodes.

Unfortunately, heavy metal sensitive electrodes cannot be easily integrated with paper-based solution sampling as heavy metals have strong affinity towards paper substrates. In this work, overview of current approaches aiming at controlling the super-Nernstian response which usually occurs when using unmodified paper substrates with coupled with ion-selective electrodes will be reviewed. These include the modification of paper substrates with inorganic salts, acid treatment, creating a physical barrier on the paper substrates (sputtered metal), or modifying paper with ion-selective membrane components. These techniques either deplete the active sites on the paper substrates or prevent the heavy metal ions from reaching active sites, improving the response of ion-selective electrodes when coupled with paper-based solution sampling.

Results clearly indicate that the composition of traditional paper substrates is not optimized for the use in sensitive heavy metal-based analytical systems. Thus, current methodologies in controlling or eliminating super-Nernstian response of ion-selective electrodes when coupled with paper-based solution sampling require separate consideration for manufacturing of an advanced paper material that would be inert to heavy metals.

Speaker: Grzegorz Lisak - Nanyang Technological University Singapore
Grzegorz Lisak obtained his M.Sc. (Chem. Eng.) in physical chemistry in 2007 from Poznań University of Technology, Poland. He obtained his D.Sc.(Tech.) in analytical chemistry in 2012 from Åbo Akademi University, Finland. Between 2013 and 2015 he has been a research fellow at University of Wollongong, Australia and Malmö University, Sweden. He joined Nanyang Technological University Singapore in 2016 as assistant professor and was tenured to associate professor in 2022. Since 2017, he is a director of Residues and Resources Reclamation Center (in 2022 converted to Resource Recovery Programme) at Nanyang Environment and Water Research Institute. Since 2019, he is the associated editor of Chemosphere (IF= 8.943), Elsevier. His interests cover electrochemical sensors, in particular potentiometric ion sensors, new sensor design, paper based analytical systems, and contaminated site assessment.