biostudies-literatureRoy SKEuropean Research Council1373-1379https://www.ebi.ac.uk/biostudies/studies/S-EPMC11665774biostudies-literatureUnknown23(6)We introduce two water-soluble excited state intramolecular proton transfer (ESIPT) based fluorescent turn-on probes responding to inorganic polyphosphates. These ESIPT probes enable specific detection of short-chain inorganic polyphosphates over a range of different condensed phosphates. The probes are weakly emissive in their off-state due to the blocking of ESIPT by Cu²⁺ coordination. Removal of the copper ion through decomplexation by the analyte accesses the on-state. The probes detect polyphosphates over other biologically occurring phosphates, pyrophosphate, and nucleotides such as ATP, ADP, GTP. An optimal fluorescence response is observed with the short-chain polyphosphate polyP₈. Furthermore, the probe shows selectivity towards linear polyphosphates over cycOrganic & biomolecular chemistryESIPT fluorescence turn-on sensors for detection of short chain inorganic polyphosphate in water.PMC11665774864246Hinkelmann RJessen HJMoser SDurr-Mayer TRoy SKfalseESIPT fluorescence turn-on sensors for detection of short chain inorganic polyphosphate in water.We introduce two water-soluble excited state intramolecular proton transfer (ESIPT) based fluorescent turn-on probes responding to inorganic polyphosphates. These ESIPT probes enable specific detection of short-chain inorganic polyphosphates over a range of different condensed phosphates. The probes are weakly emissive in their off-state due to the blocking of ESIPT by Cu²⁺ coordination. Removal of the copper ion through decomplexation by the analyte accesses the on-state. The probes detect polyphosphates over other biologically occurring phosphates, pyrophosphate, and nucleotides such as ATP, ADP, GTP. An optimal fluorescence response is observed with the short-chain polyphosphate polyP₈. Furthermore, the probe shows selectivity towards linear polyphosphates over cyc2025-01-01T00:00:00Z2025 Feb2025-04-06T13:59:27.959Z2025-04-06T13:59:27.959ZS-EPMC116657743971478210.1039/d4ob01926a