A solid-phase micro extraction (SPME) device comprises a supporting substrate 10 in the form of a sheet of paper board, of cardboard or of plastics material having first and second major surfaces 11, 13 and first and second end regions. A layer 12 of gas barrier material is applied over the first end region of a least the first major surface. A volatile compound sorptive coating 14 is disposed on the gas barrier material on the first major surface. This may be on only a portion of the layer of gas barrier material, such as a central region of the first end region of the first major surface where a depression or indentation 15 may be formed for this purpose. The second end region of the substrate is dimensioned to serve as a handheld section (16, fig 1) of the device. The SPME device may be used in combination with a breath sampler in the form of a hollow container formed from an outer tubular sleeve (24, fig 3) and an inner tubular part (22, fig 3). The device may be used as a test for a Helicobacter Pylori infection.
