Embodiments of the disclosure generally relate to a system, apparatus and method for testing a coating over a semiconductor chamber component. In one embodiment, a test station comprises a hollow tube, a sensor coupled to a top end of the tube and a processing system communicatively coupled to the sensor. The hollow tube has an open bottom end configured for sealingly engaging a coating layer of the semiconductor chamber component. The sensor is configured to detect the presence of a gaseous byproduct of a reaction between a reagent disposed in the hollow tube and a base layer disposed under the coating layer. The processing system is configured to determine exposure of the base layer through the coating layer in response to information about the presence of the gaseous byproduct. In another embodiment, the processing system is communicatively coupled to each sensor of a plurality of test stations.