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- Improving the extraction of Ara h 6 (a peanut allergen) from a chocolatebased matrix for immunosensing detection: Influence of time, temperature and additivesPublication . Alves, Rita C.; Pimentel, Filipa B.; Nouws, Henri P.A.; Silva, Túlio H.B.; Oliveira, M. Beatriz P.P.; Delerue-Matos, CristinaThe extraction of Ara h 6 (a peanut allergen) from a complex chocolate-based food matrix was optimized by testing different temperatures, extraction times, and the influence of additives (NaCl and skimmed milk powder) in a total of 36 different conditions. Analyses were carried out using an electrochemical immunosensor. Three conditions were selected since they allowed the extraction of the highest levels of Ara h 6. These extractions were performed using 2 g of sample and 20 ml of Tris-HNO3 (pH = 8) containing: a) 0.1 M NaCl and 2 g of skimmed milk powder at 21 C for 60 min; b) 1 M NaCl and 1 g of skimmed milk powder at 21 C for 60 min; and c) 2 g of skimmed milk powder at 60 C for 60 min. Recoveries were similar or higher than 94.7%. This work highlights the importance to adjust extraction procedures regarding the target analyte and food matrix components.
- Detection of Arah1 (a major peanut allergen) in food using an electrochemical gold nanoparticle-coated screen-printed immunosensorPublication . Alves, Rita C.; Pimentel, Filipa B.; Nouws, Henri P.A.; Marques, Raquel C.B.; González-García, María Begoña; Oliveira, M. Beatriz P.P.; Delerue-Matos, CristinaA gold nanoparticle-coated screen-printed carbon electrode was used as the transducer in the development of an electrochemical immunosensor for Ara h 1 (a major peanut allergen) detection in food samples. Gold nanoparticles (average diameter=32 nm) were electrochemically generated on the surface of screen-printed carbon electrodes. Two monoclonal antibodies were used in a sandwich-type immunoassay and the antibody–antigen interaction was electrochemically detected through stripping analysis of enzymatically (using alkaline phosphatase) deposited silver. The total time of the optimized immunoassay was 3 h 50 min. The developed immunosensor allowed the quantification of Ara h 1 between 12.6 and 2000 ng/ml, with a limit of detection of 3.8 ng/ml, and provided precise (RSD <8.7%) and accurate (recovery >96.6%) results. The immunosensor was successfully applied to the analysis of complex food matrices (cookies and chocolate), being able to detect Ara h 1 in samples containing 0.1% of peanut.
- Improving the extraction of Ara h 6 (a peanut allergen) from a chocolate-based matrix for immunosensing detection: Influence of time, temperature and additivesPublication . Alves, Rita C.; Pimentel, Filipa B; Nouws, Henri P.A.; Silva, Túlio H B; Oliveira, M Beatriz P P; Delerue-Matos, CristinaThe extraction of Ara h 6 (a peanut allergen) from a complex chocolate-based food matrix was optimized by testing different temperatures, extraction times, and the influence of additives (NaCl and skimmed milk powder) in a total of 36 different conditions. Analyses were carried out using an electrochemical immunosensor. Three conditions were selected since they allowed the extraction of the highest levels of Ara h 6. These extractions were performed using 2g of sample and 20ml of Tris-HNO3 (pH=8) containing: a) 0.1M NaCl and 2g of skimmed milk powder at 21°C for 60min; b) 1M NaCl and 1g of skimmed milk powder at 21°C for 60min; and c) 2g of skimmed milk powder at 60°C for 60min. Recoveries were similar or higher than 94.7%. This work highlights the importance to adjust extraction procedures regarding the target analyte and food matrix components.