Ochratoxin A Determination in Beer by Solid-Phase Microextraction Coupled to Liquid Chromatography with Fluorescence Detection:  A Fast and Sensitive Method for Assessment of Noncompliance to Legal Limits

A solid-phase microextraction-liquid chromatography-fluorescence detection (SPME−LC−FD) method for the determination of ochratoxin A (OTA) in commercial beer samples was developed for the first time using a 60 μm thick poly(dimethylsiloxane)/divinylbenzene (PDMS/DVB) fiber. The procedure required a very simple sample pretreatment, an isocratic elution, and provides a selective extraction. All of the factors influencing fiber adsorption (extraction time, temperature, pH, and salt addition) and desorption of the analyte (desorption and injection time and desorption solvent mixture composition) have been investigated. The linear range investigated in beer was 0.03−2 ng/mL; within-day and between-days relative standard deviation in beer were 4.3 and 5.9%, respectively. The limit of quantification in spiked beer was 53 pg mL^-1, well below all European regulatory levels.