Yang Mingpeng, Silva Rochelle, Zhao Ke, Ding Ruiyu, Foo Jit Loong Cyrus, Ge Liya, Lisak Grzegorz
School of Automation, Nanjing University of Information Science and Technology, 219 Ningliu Road, Nanjing 210044, China.
Residues and Resource Reclamation Centre, Nanyang Environment and Water Research Institute, Nanyang Technological University, 1 Cleantech Loop, CleanTech One, 637141, Singapore, Singapore.
Analyst. 2024 Aug 19;149(17):4351-4362. doi: 10.1039/d4an00841c.
Paper-based microfluidics combined with potentiometric measurement has emerged as an attractive approach for detecting various chemical ionic moieties. Detection of heavy metal ions, using paper substrates as solution sampling and delivery systems remains challenging despite efforts to introduce several physico-chemical paper substrate modifications to stop adsorption of ions onto the paper substrates. This study quantitatively investigates the adsorption of heavy metal ions on the paper substrates during paper-based potentiometric measurements and explains the super-Nernstian response of potentiometric sensors through local depletion of heavy metal ions from the solution. Consequently, based on the investigated ion adsorption, a corrective potential protocol was established for the electrodes coupled with paper-based solution sampling by predicting interference free sensor response from paper-based measurement. Furthermore, the ion adsorption was also recorded for mixed metal ion solutions to understand competitive primary/interfering ions adsorption onto the paper substrates and establish corrective measures to predict interference free sensor response. In this method, no modifications of the paper substrates are necessary before actual potentiometric measurements. The proposed corrective protocol allows prediction of sensor response based on the paper-based solution sampling potentiometric measurement, providing a simple methodological approach based on correction of potential readout of the potentiometric sensor, thus completely resigning from the need of modifying paper substrate for measurements of heavy metal ions.
基于纸张的微流控技术与电位测量相结合，已成为检测各种化学离子部分的一种有吸引力的方法。尽管人们努力对纸质基材进行多种物理化学改性，以阻止离子吸附到纸质基材上，但使用纸质基材作为溶液采样和输送系统来检测重金属离子仍然具有挑战性。本研究定量研究了基于纸张的电位测量过程中重金属离子在纸质基材上的吸附情况，并通过溶液中重金属离子的局部耗尽来解释电位传感器的超能斯特响应。因此，基于所研究的离子吸附情况，通过预测基于纸张测量的无干扰传感器响应，为与基于纸张的溶液采样相结合的电极建立了一种校正电位方案。此外，还记录了混合金属离子溶液的离子吸附情况，以了解主要/干扰离子在纸质基材上的竞争性吸附，并建立校正措施来预测无干扰传感器响应。在这种方法中，在实际电位测量之前无需对纸质基材进行改性。所提出的校正方案允许基于基于纸张的溶液采样电位测量来预测传感器响应，提供了一种基于校正电位传感器电位读数的简单方法，从而完全无需为测量重金属离子而对纸质基材进行改性。
