System and method for analysing and measuring ammonia levels in a sample

A system for sensing and measuring ammonia in a breath sample, comprising:

• an ammonia sensor, and
• a sampling means for capturing and directing a breath sample from a subject to the ammonia sensor,
• wherein:
• the ammonia sensor comprises a conducting polymer polyaniline sensor, and
• the sampling means comprises a capture chamber, the capture chamber having an inlet and outlet and a capture chamber volume defined by the dimensions of the capture chamber, wherein the capture chamber provides a breath sample of predefined volume from the capture chamber across the ammonia sensor,
• the inlet having a first valve through which a breath is exhaled into the capture chamber, and
• the outlet having a second valve through which breath surplus to the volume of the capture chamber is expelled.