The present invention relates to a method of extracting 3-hydroxypropionaldehyde (3-HPA) and/or derivatives thereof from an aqueous solution comprising 3-HPA, the method comprising: (a) contacting the aqueous solution with chitosan and/or chitosan comprising polymers; (b) separating the 3-HPA bound chitosan and/or chitosan comprising polymers; and (c) washing the 3-HPA bound chitosan and/or chitosan comprising polymers at least once with a washing medium; wherein 3-HPA and/or derivatives thereof is in the washing medium.