One-pot derivatization facilitated resonance Rayleigh scattering and absorption dual-mode method for selective and rapid detection of phosphate in real food samples

A one-pot derivatization facilitated resonance Rayleigh scattering and absorption (abbreviated as one-pot RRS/Abs) dual-mode method was proposed for selective and rapid detection of phosphate. A one-pot derivatization reaction that takes only 5 min was introduced to generate a dual-mode spectroscopic signal and improve the selectivity. Using the derivatization agent (ammonium vanadic molybdate, AVM), spectral probe (crystal violet, CV), and sensitizing reagent (Triton X-114, TX-114), phosphate was transformed into a large supramolecular complex, resulting in a remarkable dual-mode signal response of RRS and UV–Vis absorption. The RRS signal (368 nm) and ratiometric absorption signal (A 590 nm /A 450 nm ) were linearly correlated with the phosphate concentration in the range of 0.05–1.0 µg/mL and 0.08–1.0 µg/mL, respectively. The correlation index (R 2 ) was 0.9976 and 0.9890, and the limits of detection (LOD) were 13 ng/mL and 42 ng/mL, respectively, which were lower than those obtained through most spectroscopic methods. The one-pot RRS/Abs dual-mode method was applied to detect phosphate in real food samples, with recoveries of 92.0%–110.0% and relative standard deviations (RSD) of 2.1%–6.6%. The one-pot RRS/Abs dual-mode method is rapid, selective, sensitive, convenient to operate, and capable of self-comparison, showing great promise for phosphate detection in complex samples. In addition, it offers an alternative strategy for the measurement of analytes with weak spectroscopic signals.