Inorganic phosphate regulated high luminescence NaYF4:Yb3+, Er3+ as an iron ion fluorescent nanoprobe.

[Display omitted] • Sodium hexametaphosphate (SHMP) was used to regulate the morphology and functionalization of NaYF 4 :Yb3+, Er3+ upconversion luminescent nanoprobe (UCNPs). • The UCNPs@SHMP fluorescent sensor could detect Fe(III) with low detection limit in industrial circulating cooling water. • This strategy has the potential to develop a visual method for monitoring the corrosion of circulating cooling water system. The iron ion in industrial circulating cooling water is an important indicator for early warning of equipment corrosion and control level. It is interesting to construct an upconversion luminescence iron ion nanoprobe with a common inorganic phosphate water treatment agent. Herein, inorganic phosphate sodium hexametaphosphate (SHMP) was used to regulate the morphology and functionalization of NaYF 4 :Yb3+, Er3+ upconversion luminescent nanoprobe (UCNPs) and applied to fluorometric detection of trace Fe(III) in water based on the fluorescence quenching which is caused by the selective coordination between hexametaphosphate on the surface of UCNPs and Fe(III). The structure, morphology, and luminous intensity of UCNPs were regulated by disodium hydrogen phosphate (ADSP), sodium tripolyphosphate (STPP) and sodium hexametaphosphate(SHMP). The UCNPs functionalized with SHMP has high sensitivity and selectivity for Fe(III) detection. The linear range and detection limit are 1.0–50 μM and 0.2 μM, respectively. The method has satisfactory results for the detection of trace Fe(III) in industrial circulating cooling water. [ABSTRACT FROM AUTHOR]