Ultra-fast LC-MS/MS method for the identification and prevalence of Rhodamine B in candies commonly consumed by children in Egypt

This study presents the first analytical method for detecting and quantifying Rhodamine B (RhB) dye adulteration in candy products within the Egyptian market. A high-throughput liquid chromatography-tandem mass spectrometry (LC-MS/MS) method was developed and validated for the accurate quantification of RhB in various candy samples. The method demonstrated satisfactory sensitivity, with a limit of detection (LOD) of 0.09 µg/kg and a limit of quantification (LOQ) of 0.28 µg/kg. Matrix-matched standard calibration curves exhibited excellent linearity (<i>r</i> &gt; 0.9988) over a wide concentration range (0.1–100 µg/L). The method’s accuracy and precision were validated through recovery rates (89.25%–104.13%) and relative standard deviation (RSDs) evaluation (&lt;5.87%). The robustness of the method was confirmed by varying key parameters, such as shaking time and column temperature. A comprehensive survey of 350 candy samples collected from local markets in Egypt revealed the presence of illegal RhB dye in 18 samples (5.14%), with concentrations ranging from 0.003 to 393.68 mg/kg. This high-throughput LC-MS/MS method follows green chemistry principles and provides a valuable analytical tool for regulatory agencies and food industry stakeholders to monitor and maintain food safety standards, detect banned synthetic dyes, and protect the consumers from potential health risks associated with contaminated food products.