Photoionization Ion Mobility Analyzer for On-site Measurement of Exhaled Acetone by Coupling Miniature Thermoelectric Cooling Dehydration

Abstract

The breath concentration of acetone holds significant clinical importance, the development of on-site and accurate analyzer for exhaled acetone is highly demanded. A photoionization ion mobility analyzer based on a low-pressure krypton discharge lamp has been developed for direct and rapid determination of the acetone concentration. The difficulty for sensitive measurement of acetone by vacuum ultraviolet photoionization was the strong absorption of water molecules in the breath air. An online dehydration device with a miniature thermoelectric cooling quartz trap has been developed, which was capable for reducing the relative humidity from over 90% to below 1%. The dehydration could enhance the signal intensity of acetone about 85 times. The response time of current thermoelectric cooling dehydration was only 1/20 of the Nafion tube dehydration. A limit of detection 0.02 ppm_V and linear response up to 2.0 ppm_V were achieved. The interferences from ammonia in exhaled breath was eliminated using a calibration method based on ion number density, achieving recoveries ranging from 90% to 110%. In the final, the variation trends of exhaled acetone level in healthy individuals following the ingestion of glucose under fasting conditions were carried out to demonstrate the potential application of the analyzer.