Development of a direct competitive enzyme-linked immunosorbent assay (dc-ELISA) for the detection of scopolamine in wheat

A competitive direct enzyme-linked immunosorbent assay (dc-ELISA) was developed for the detection and quantification of scopolamine (SCO) in wheat flours and cereal samples (multigrain, oat and barley). The limit of quantification (IC₂₀) of the established method was 6.00 ± 1.20 ng/g, with the limit of detection (IC₁₀) being 2.4 ± 0.6 ng/g in wheat flour with a coefficient of variation (CV) less than 20%. The assay was highly specific to SCO and nor-scopolamine, with no cross-reactivity to other similar structures. In spiked wheat flours the recoveries ranged from 84% to 104% with CVs of less than 20% and the recovery from a Food Analysis Performance Assessment Scheme (FAPAS) buckwheat control sample was 118%. A comparison of spiked wheat flour and a FAPAS control sample showed similar results to those determined by classical LC-MS/MS methods. A small retail survey of wheat flours and cereal samples was conducted using this ELISA method and a LC-MS/MS method, which showed scopolamine was not detected in any of these survey samples by either method. This method is suitable for rapid quantitation of SCO in wheat flours and cereal samples.