A New Method for the Sensitive Analysis of Ochratoxin A in House Dust

Summary

A sensitive method for the analysis of Ochratoxin A (OA) in house dust is described using capillary zone electrophoresis coupled to laser-induced fluorescence. The method’s sensitivity makes it suitable for determining OA from just 500 mg house dust. The house dust is extracted with acetonitrile. The extract is purified in a two-step sample clean-up. The first step is liquid-liquid extraction with dichloromethane followed by normal-phase solid phase extraction. The estimated recovery of OA exceeds 82%. Capillary electrophoresis with a developed sample stacking procedure with reversed polarity provides a low limit of detection of 0.2 ng g⁻¹ in house dust. The buffer system and the injected volume are optimized. To enhance reproducibility and ensure proper peak identification, an internal standard was added to the method.