A gas-liquid separator apparatus and device, particularly for use in connection with medical gas analyses, such as capnography, is provided. The separation chamber tapers in a direction from the blow down port to the dry gas outlet port providing increased surface area in the lower portion of the separation chamber for providing capillary volumes or regions. A solid body is disposed in the separation chamber to provide a surface of the capillary volumes and to decrease the effective volume of the separation chamber. The body can be used to occlude the dry gas outlet port upon tipping of the separation chamber at greater than a predetermined angle. A number of internal fins extend inwardly from the side wall and bottom surface into the separation chamber to form capillary volumes in cooperation with the side wall, bottom surface and/or solid body.