TY - GEN A1 - Riedel, Soraya T1 - Ochratoxin A detection by an immunomagnetic assay and smartphone-based amperometry N2 - The demand for miniaturized analytical devices monitoring important parameters in the food and medical industry has increased strongly in the past decades. With fast progress, smart technologies are finding their way into our everyday life. For the future, it is, therefore, a major goal to also link analytical methods with smart technologies to create user-friendly on-site devices. In food industry the monitoring of harmful substances such as dioxins, heavy metals or mycotoxins plays a key role, since the European Commission prescribes legal limits for various food products and beverages. Therefore, companies often have their own laboratories and trained personnel. For one of the most abundant and toxic mycotoxins, Ochratoxin A (OTA) we want to present an electrochemical detection system in which the read-out can be performed with a smartphone connected via Bluetooth to a miniaturized potentiostat. The recognition of OTA is performed with specific antibodies in a competitive assay format. Anti-OTA-antibodies were captured on magnetic beads on which the competitive binding between OTA and an OTA horseradish peroxidase (HRP) tracer was performed. To quantify OTA, the enzymatic reaction of the tracer with 3,3′,5,5′-tetramethylbenzidine (TMB) and H2O2 is employed. Oxidized TMB, which is enzymatically produced by the reduction of H2O2, is quantified by amperometry with screen-printed electrodes in a custom-made flow system. Since it is well-known that oxidized TMB can precipitate on electrode surfaces, we have studied pitfalls of the electrochemical detection of TMB. By cyclic voltammetry we have compared the stability of the electrochemistry of TMB at different electrode materials (gold and carbon) and pH values (pH 1 and pH 4). It was found that a stable response of the electrode could be achieved at pH 1 on gold electrodes. Thus, we applied these reaction conditions for amperometric detection of TMB in the OTA assay. The results of the electrochemical detection method are in good correlation with the photometric detection of TMB. To demonstrate the applicability, we tested our system with OTA-spiked beer and performed the measurement via smartphone. T2 - Rapid Methods Europe CY - Online meeting DA - 01.02.2021 KW - Ochratoxin A KW - Cyclic voltammetry KW - Amperometry KW - Smartphone KW - Electrochemistry PY - 2021 UR - https://opus4.kobv.de/opus4-bam/frontdoor/index/index/docId/52095 AN - OPUS4-52095 N1 - Geburtsname von Riedel, Soraya: Höfs, S. - Birth name of Riedel, Soraya: Höfs, S. AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany