title: Indirect determination of aflatoxin B₁ in beer via a multi-commuted optical sensor.
abstract: This paper reports the determination of aflatoxin B₁ (AFB₁), one of the most carcinogenic substances known. A multi-commuted flow injection-solid phase spectroscopy (FI-SPS) system combined with photochemically induced fluorescence (PIF) was developed, for the first time, for its quantitative determination. A strongly fluorescent degradation product was obtained on-line by irradiation with ultraviolet light. The determination was carried out by measuring the fluorescence intensity of the photo-product at 353/424 (λ (ex)/λ (em)), once retained on C₁₈ silica-gel filling the flow-cell. A linear dynamic range of 0.09-12 µg l⁻¹, detection limit as sensitive as 29 ng l⁻¹ and a relative standard deviation (RSD) of 1.4% were obtained. The method proposed was satisfactorily applied to the determination of AFB₁ in different types of beer (normal and non-alcoholic). Hydrophobic compounds were eliminated from beer samples and AFB₁ was extracted with acetonitrile by solid-phase extraction on C₁₈ sorbent. Recoveries of the target compound from spiked beers were between 94 and 106%. The results obtained in the analysis of real samples are in good agreement with those provided by a reference chromatographic method.
authors.affiliation: Department of Physical and Analytical Chemistry, University of Jaén, Jaén, Spain.
authors.forename: Lucía
authors.initials: L
authors.lastname: Molina-García
authors.forename: Maria Luisa
authors.initials: ML
authors.lastname: Fernández-de Córdova
authors.forename: Antonio
authors.initials: A
authors.lastname: Ruiz-Medina
mesh_terms: D016604:Aflatoxin B1 / Q000032:analysis*; D057205:Automation, Laboratory; D001515:Beer / Q000032:analysis*; D001628:Beverages / Q000032:analysis; D002273:Carcinogens / Q000032:analysis*; D005506:Food Contamination; D005513:Food Inspection / Q000295:instrumentation / Q000379:methods; D006863:Hydrogen-Ion Concentration; D057230:Limit of Detection; D010777:Photochemistry / Q000379:methods; D015203:Reproducibility of Results; D052616:Solid Phase Extraction; D013050:Spectrometry, Fluorescence / Q000379:methods; D013997:Time Factors
chemical_list: D002273:Carcinogens; D016604:Aflatoxin B1