Gas sensor, scanning electrochemical gas microscope, and method of preparing gas sensor

A gas sensor for measuring a gas content in an electrolyte, the gas sensor comprising:

• an at least partially closed capillary tube, comprising:
• a first channel;
• a second channel;
• and
• a tip,
• wherein the first channel and the second channel are separated by a septum, and
• wherein the first channel and the second channel are closed by the tip;
• a first electrode that is located in the first channel, extends to an outer surface of the tip, and is exposed on the outer surface of the tip;
• a second electrode that is located in the second channel, extends to the outer surface of the tip, is exposed on the outer surface of the tip, and is spaced apart from the first electrode;
• an electrolyte that is in contact with the outer surface of the tip, is in contact with the first electrode and the second electrode, and is exposed to an outer surface of the gas sensor;
• a voltage source disposed between the first electrode and the second electrode;
• and
• a current meter disposed between the first electrode and the second electrode,
• wherein the electrolyte is not present in the first channel or the second channel, and
• wherein the gas comprises an explosive compound.