University of Minnesota, Department of Chemistry, 207 Pleasant Street SE, Minneapolis, Minnesota 55455, United States.
Anal Chem. 2022 Nov 1;94(43):14898-14905. doi: 10.1021/acs.analchem.2c02261. Epub 2022 Oct 19.
While paper is an excellent material for use in many other portable sensors, potentiometric paper-based sensors have been reported to perform worse than conventional rod-shaped electrodes, in particular in view of limits of detection (LODs). Reported here is an in-depth study of the lower LOD for Cl measurements with paper-based devices comprising AgCl/Ag transducers. Contamination by Cl from two commonly used device materials─a AgCl/Ag ink and so-called ashless filter paper─was found to increase the concentration of Cl in paper-contained samples far above what is expected for the spontaneous dissolution of the transducer's AgCl, thereby worsening lower LODs. In addition, for the case of Ag, the commonly hypothesized adsorption of metal cations onto filter paper was found not to significantly affect the performance of AgCl/Ag transducers. We note that in the context of chemical analysis, metal impurities of paper are often mentioned in the literature, but Cl contamination of paper has been overlooked.
虽然纸张是许多其他便携式传感器中非常出色的材料，但与传统的棒状电极相比，基于纸张的电位传感器的性能较差，尤其是在检测限（LOD）方面。本文深入研究了基于纸张的设备中包含的 AgCl/Ag 换能器的 Cl 测量的较低 LOD。发现来自两种常用器件材料的 Cl 污染——一种 AgCl/Ag 墨水和所谓的无灰滤纸——会使包含纸张的样品中的 Cl 浓度远远高于自发溶解换能器的 AgCl 所预期的浓度，从而降低较低的 LOD。此外，对于 Ag 的情况，我们发现通常假设的金属阳离子在滤纸上的吸附不会对 AgCl/Ag 换能器的性能产生重大影响。我们注意到，在化学分析的背景下，文献中经常提到纸张中的金属杂质，但纸张的 Cl 污染却被忽视了。
