Detection method for detecting existence of liquid in transparent glass tube

The invention belongs to the technical field of flow path systems of chemical instruments, particularly relates to a detection method for detecting whether liquid exists in a transparent glass tube or not, and provides the following scheme aiming at the problem that when an existing passing medium is low in light transmittance or light-tight, a detection device is prone to failure. The method comprises the following steps that S1, a detection structure for detecting whether liquid exists in a transparent glass tube or not comprises a transparent tube, a light-emitting diode, a photosensitive diode, a control system and an auxiliary device, the light-emitting diode is installed on one side of the transparent tube, the photosensitive diode is installed on the other side of the transparent tube, and the device can be used for detecting a completely transparent medium and detecting liquid in the transparent glass tube; the transparent tube can be used for detecting liquid media such as colored liquid media and tu