a device and method for testing a fiber - composite component , which is to be processed by means of bonding , for the presence of at least one substance out of a selection of possible contaminants . a surface heating device for regional heating of a part - zone of the fiber - composite component to be bonded is performed for desorption of contaminants . a sensor array with a plurality of sensors detects contaminants in the gas phase , and a control device ascertains and signals contaminations which are found . an extractor device can be employed to extract machining dust from the fiber - composite component to a desorption device .