A symmetrical imine-linkage colorimetric probe for sequential detection of Al³⁺ and PO₄^3- ions

Affordable and incredibly sensitive sustainable sensors for recognizing Al3+ ions have enormous practical applications. A simple and reliable sensor DPAB has been introduced is extremely susceptible regarding Al3+ ions and exhibits an incredible color change in DMSO and DMSO-H2O (9:1 v/v) solution, allowing us to visually distinguish Al3+ ions from other metals and anions. The limit of detection (LOD) values for Al3+ and POt ions are determined to be in the nM range considerably lower than other chemosensors described in the literature. Additionally, for on-the-spot detection, the probe may also be utilized in the test strips with a superior selectivity for Al3+and POt. Moreover, we also performed the smartphone-based technique for the practical utility of DPAB in the DMSO-H2O (9:1 v/v) solution. Sequentially including Al3+ and POt in the DPAB solution, the sensor's spectral responses and apparent color shift can be switched backward and forward. This can be conceptualized as a complementary " INHIBIT" logic gate at the molecular phase. We have developed a molecular-scale subsequent memory device based on a reversible and repeatable detection system that exhibits "Writing-Reading-ErasingReading" and "Multi-write" functionalities as binary logic. The effectiveness of DPAB and DPAB-Al3+ complex suggests that DPAB may be used as a sensitive probe and be applied to the analysis of real samples.