It is an object to obtain a liquid crystal display device in which a contact defect is reduced, increase in contact resistance is suppressed, and an opening ratio is high. Examples of such compounds include menthol, peppermint, cinnamon and vanilla flavors and water soluble dyes. The optical system has a variable focus lens configured to control the position of the focal point of the laser beam along the optical axis within the cutting zone. Leakage current from the first chuck element is thus reduced to virtually zero, hence enabling increased current sensitivity, and the reduced capacitance thus provided by the second chuck element decreases charging periods, hence reducing settling times. Calibration checking devices and methods of mandating their use at regular time intervals are described, to ensure maintenance of the accuracy of breath tests. Additional conduits and mounting points for componentry such as valves and fittings may be machined into the block in fluid connection with the tubing conduits.