Total Determination and Chemical Speciation of Feand Fe Species in Water Based on the Fluorescence Quenching of 4, 5- Dihydroxy-1, 3-benzenedisulfonic Acid' as a Sensing Platform.

Total quantification and speciation of Fe and Fe at trace levels in aqueous environments has emerged as an imperative analytical challenge for ecological systems and public health. Implementation of wavelength-dependent spectrochemical methodologies based on formation of chromogenic Fe chelate for Fe quantification in aqueous media also remains intrinsically challenging owing to intrinsic self-absorbance, and spectral convolution. Thus, the current study reports the development of a direct and selective eco-friendly spectrofluorometric probe for Fe detection in water. The sensor 4, 5- dihydroxy-1, 3-benzenedisulfonic acid (Tiron) displays strong emission which undergoes significant quenching in the fluorescence intensity (at λ = 290/350 nm) upon reaction with Fe at pH 8-9 in the presence of interfering metal ions, allowing for rapid and efficient detection. The probe was sensitive to implement the produced change in color with a total assay reaction time less than 3 min. Detailed spectroscopic investigation reveal a high binding affinity between the Fe ions and the sensor, ascribed to specific complex formation. The limit of detection (LOD) and quantitation (LOQ) and linear dynamic rang (LDR) of the assay were 0.015, 0.04 and 0.05-5 mg L Fe, respectively. The probe was favorably used for total detection and sequential speciation of trace levels of Fe & Fe in water after oxidation of the former to Fe. Spectroscopic studies suggested high coordinating attraction and stability between the sensor and Fe ions. The probe was fruitfully validated by comparing the results with the official inductively coupled plasma-optical emission spectrometry (ICP-OES) data using Student t and F tests signifying the high precision, accuracy and reliability for Fe detection in water samples. The attractive features of the probe comprises its simplicity, no usage of organic solvents, short reaction time; high reactivity, stable response, selective towards Fe, and sensitive for total quantification of iron species. The probe can assist as a talented tool for application in regions of limiting resources specifically concerning iron pollution.