Abstract: A method and a device are provided for determining a content of at least one foreign substance in a matrix of a solid or liquid food. At least one reagent area for providing at least one reagent has a receptacle for a replaceable reagent container for replaceably connecting a sample container including at least the matrix; a transfer line is provided between the reagent area and the reaction area, by which the at least one reagent can be fed to the reaction area; a sensor area is provided for demonstrating the foreign substance released from the matrix; a carrier gas line is provided between the reaction area and the sensor area, by which the released foreign substance can be fed to the sensor area; and an output line is provided through which the dissolved foreign substance can be fed outward from the sensor area.