Simultaneous determination of five aluminum lake dyes in chewing gum by HPLC with photodiode array detection

Abstract

A simple and rapid method has been developed and validated for the determination of five food aluminum lake dyes (Tartrazine Al lake, Sunset Yellow Al lake, Ponceau 4 R Al lake, Allura Red Al lake and Brilliant Blue Al lake) in chewing gum. The dye portions of the target aluminum lakes were simultaneous extracted with 0.25 M NaOH and cleaned up by liquid-liquid extraction with dichloromethane, followed by further purification using Oasis WAX solid-phase extraction (SPE) cartridges. Analytes were separated by HPLC using an Inertsil ® ODS-3 column coupled to a photodiode array detector. The amounts of the aluminum lake dyes were finally quantified and indicated as their dye portions using corresponding calibration curves over ranges of 0.5 to 50 µg ml⁻¹, with correlation coefficients >0.9999. Recoveries of the dye parts in aluminum lake dyes (spiked at levels of 1, 5, 25 µg g⁻¹) ranged from 72.5 to 116.4%, with relative standard deviations between 0.9 and 6.5%. Limits of detection and limits of quantification for all analytes were 0.15 and 0.50 µg g⁻¹, respectively. This method was successfully applied in real samples of chewing gum.

Keywords:

• chromatography
• HPLC
• extraction
• clean-up
• colours
• confectionary

Acknowledgements

This study was supported by the Science Research Foundation of Ministry of Health of the People's Republic of China (grant number 200902009).