Quantitative analysis of patulin in apple juice by thin-layer chromatography using a charge coupled device detector

Abstract

A method was developed and validated in-house for the detection and quantification of patulin in apple juice concentrate using a charge coupled device (CCD) on thin-layer chromatography (TLC) plates. Samples were extracted with ethyl acetate and then cleaned-up by extraction with a sodium carbonate solution. The method showed a mean recovery of 95%. The quantification and detection limit were 14 µg l⁻¹ and 0.005 µg per spot, respectively. The CCD camera is sufficiently sensitive to detect changes in spot fluorescence intensity caused by small differences in mycotoxin concentration under homogeneous illumination from a UV light source. The results of validation confirmed the efficiency of the method, which is sensitive enough to be used to quantify patulin in apple juice by producers or for government monitoring/survey programs. The method was applied to the analysis of 16 apple juice concentrate samples and patulin levels ranged from 15 to 46 µg l⁻¹. This study demonstrated the applicability of the TLC–CCD technique as a tool for monitoring patulin in apple juice.

Keywords:

• apple juice
• charge-coupled device imaging
• patulin
• thin-layer chromatography

Acknowledgements

The authors thank the Toxicology Laboratory at the Institute of Food Science and Technology of the Federal University of Rio Grande do Sul, the Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq) for financial support and Coordenadoria para Aperfeiçoamento de Pessoal de Nível Superior (CAPES) for graduate scholarships.