Failure detection method, failure detection system, and electrospray ion source

A failure detection system comprising:

• a light source configured to irradiate an inside of an electrospray ion source with light;
• a scattered light information acquisition device configured to acquire scattered light information that is information of scattered light scattered by a droplet generated by electrospraying;
• and
• a processing device that stores, in a storage unit, determination reference information indicating a relationship between a parameter of a channel system of a liquid chromatography device in a normal state and the scattered light information, wherein
• the processing device includes:
• a scattered light information acquisition unit configured to acquire the scattered light information from the scattered light information acquisition device;
• and
• a determination processing unit configured to determine a failure of a channel system in the liquid chromatography device by detecting a change in acquired scattered light information relative to a value of the determination reference information by comparing the acquired scattered light information and the determination reference information.