Phosphate ion (Pi) is an inorganic anion widely distributed and commonly regarded as a significant indicator of water eutrophication, and thus it is urgent to develop convenient, cost-effective and reliable analytical approaches for the monitoring of Pi for water quality control. In this work, we propose the high-performance dual-channel ratiometric colorimetric sensing of Pi based on the analyte-triggered differential oxidase-mimicking activity changes of oxidized Ce-Zr bimetal-organic frameworks (oxidized UiO-66(Ce/Zr)). By integrating two types of metal nodes with different functions into one framework structure, the proposed oxidized UiO-66(Ce/Zr) not only exhibits excellent activity to catalyze the chromogenic oxidation of both 3,3′,5,5′-tetramethylbenzidine (TMB) and 2,2′-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) due to oxidase-like active Ce⁴⁺/Ce³⁺ sites but also provides main Zr⁴⁺ sites to specifically recognize Pi. When Pi is in presence, it is rapidly adsorbed onto oxidized UiO-66(Ce/Zr) and changes the surface chemistry of the latter, leading to differential enzyme-like activity changes towards the two chromogenic substrates TMB and ABTS. Based on this finding, a dual-channel ratiometric colorimetric method was established for the sensitive determination of Pi. Compared to conventional single-signal colorimetric sensors, our method offered a widened linear detection scope from 3.3 to 666.7 μM. Also, robust and accurate analysis of Pi in various water matrices was demonstrated, indicating our method’s great potential in practical applications.

磷酸根离子（Pi）是一种分布广泛的无机阴离子，通常被认为是水富营养化的重要指标，因此迫切需要开发一种方便，经济高效且可靠的分析方法来监测Pi以控制水质。在这项工作中，我们基于氧化的Ce-Zr双金属有机骨架（氧化的UiO-66（Ce / Zr））的分析物触发的差分氧化酶模拟活性变化，提出了对Pi的高性能双通道比色比色传感。 。通过将两种具有不同功能的金属节点整合到一个框架结构中，拟议的氧化UiO-66（Ce / Zr）不仅具有出色的催化3,3'，5,5'-四甲基联苯胺的发色氧化的活性（ TMB）和2⁴⁺ / Ce ³⁺站点，但也提供主要的Zr ⁴⁺站点以专门识别Pi。当Pi存在时，它会迅速吸附到氧化的UiO-66（Ce / Zr）上，并改变后者的表面化学性质，从而导致针对两种生色底物TMB和ABTS的不同的类酶活性变化。基于这一发现，建立了一种双通道比色比色法，用于灵敏测定Pi。与传统的单信号比色传感器相比，我们的方法提供了从3.3到666.7μM的宽线性检测范围。此外，还展示了对各种水基质中Pi的可靠而准确的分析，表明我们的方法在实际应用中具有巨大的潜力。