Diode Laser-Based Ketosis Sensor

The nutritional health of field personnel deployed for extended periods is a long-standing problem critical to military troop performance and readiness. The combination of extraordinary physical stresses and the limited provisions carried by militaryfield personnel result in large caloric imbalances. Personnel may experience: loss of strength and decreased endurance; loss of motivation and decreased mental alertness; weight loss, and severe electrolyte imbalances. Measurements of metabolite levelsin body fluids (blood, plasma, serum and urine) and respiratory gases are well-established, reliable measures of human metabolic status; but existing laboratory instruments are not portable. We propose to deliver at the end of Phase II a low power,fast-response, hand-held device capable of truly non-invasive detection of human metabolic status in healthy, diseased (diabetes maintenance), and stressed states.Our measurement approach quantifies acetone in exhaled breath using a chemical conversion of acetone. Target specifications for the deliverable sensor include 1 ppm acetone sensitivity; battery operation with no more than 5 Watt power requirement; 10second response time; measurement dynamic range to 1000 ppm; and less than 1 kg total weight. The Phase I laboratory instrument shows better sensitivity than was targeted, and achieved minimum detectable acetone concentrations of <1 ppm. Successfulconclusion of the Phase II research will result in a portable sensor for the measurement of human metabolic status using only exhaled breath. This sensor technology has applications in the significant field of diabetic screening and case management inboth military and private sector markets.