To provide a sampling device comprising a blob having resistance to changes in its hydrogen releasing capacity due to moisture absorption from environmental exposure during long term periods of shipping and storage.

There is provided a detection device for molten metal. The detection device comprises: a sample cup having a cavity configured to receive a sample of molten metal; and a blob arranged in the cavity. The blob includes a carbide stabilizing element, and a hydrogen releasing material including a hydroxide of an alkaline earth metal. The blob is provided for use in detecting phase change temperatures during solidification of a sample of molten cast iron. The blob is also resistant to moisture gain and moisture loss during transport and storage. There are also provided a method of detecting phase change temperatures of the molten iron or molten cast iron sample using the blob, and a method of manufacturing the blob.