Preparation Of Rhodamine B Fluorescent Probe Containing Benzothiazole Substructure And Its Application In The Detection Of Salicylic Aci

Salicylic acid(SA),as a crucial molecule,is not only involved in plant immune regulation,but is also of wide interest in the ecological environment and human health owing to its diverse application in life.However,the development of rapid,sensitive and convenient tools for the selective detection of SA remains a great challenge.Fluorescent molecular probe technology is highly sensitive,selective,simple to operate,low-cost,suitable for naked-eye detection and nondestructive detection,and also has the ability to detect organic small molecules.Therefore,the detection of SA in phytoplankton as well as in real samples by fluorescent molecular probes is a more ideal method.In this study,based on the previous work of our group,we used a new synthetic method,different from the traditional rhodamine backbone five-membered spirocyclic probes,we designed a series of rhodamine B fluorescent probes containing six-and five-membered benzothiazole substructures,and initially compared their fluorescence properties by fluorescence spectroscopy and DFT theoretical calculations.Among them,probe 1 showed good sensing performance for SA,including fast response(<1 min),high selectivity,high sensitivity,good photostability,low detection limit(1 n M)and reversibility for naked-eye recognition.Meanwhile,we conducted a preliminary exploration of the recognition mechanism of probe 1 with SA by NMR titration.As a representative fluorescence mode,probe 1 can visualize SA in plant healing tissues and plant root tips for possible plant biology studies.And by preparing portable test strips by loading probe 1 on filter paper,we successfully detected excess SA on the surface of food,which can serve as a warning for SA-sensitive individuals.This proof-of-concept study highlights the potential application of probe 1 as a molecular tool for monitoring SA in plant and food,and it would be possible used to detect SA in other fields of sewage detection,food industry,and cosmetics residue detection,with an economical,reusable and fast-responding performance.