All-solid-state K⁺ sensing array based on Au@polystyrene nanocomposites

All-solid-state ion selective electrodes (ASS-ISEs) are easy to miniaturize and array, meeting the needs of home sensing devices. However, ASS-ISEs still faces challenges in accuracy and stability due to basic potential changes caused by non-specific adsorption of charged background compositions and the complex electrode preparation steps. To this end, our group successfully subtracted the background signal by integrating a self-calibrating channel in the sensing array and simplified the electrode preparation steps by preparing multi-functional PS-Au nanocomposites. However, the uniformity and gold content of PS-Au nanocomposites are difficult to control, so Au@PS nanocomposites are prepared as sensor materials in this paper to further reduce the differences between batches of electrodes. K⁺ Au@PS sensing array can be obtained by directly dropping Au@PS nanocomposites on the screen-printed carbon electrodes (SPCEs), which shows a near Nernstian behavior in the range 1.0 × 10⁻³ M to 0.3 M and good reproducibility in real sample testing. The detection results by K⁺ Au@PS sensing array for K⁺ in human morning urine agreed well with that tested by ICP-AES, which make the K⁺-ASS-ISE suitable for home health monitoring. Graphical Abstract: (Figure presented.)