Test and Evaluation of an Energetics Science Incorporated Model 7660 Electrochemical Hydrazines Analyzer

摘要

An Energetics Science Incorporated Model 7660 MMH analyzer was tested and evaluated for continuous real-time measurement of Hz, MMH, and UDMH in air. Sensitivity to the hydrazines was approximately 0.06 ppm Hz, 0.04 ppm MMH, and 0.025 ppm UDMH. Accuracy and precision, determined at 0.1-ppm concentrations on an analyzer calibrated daily, were between 20% and 40% for the three hydrazines. Analyzer response time increased with age (use) of the sensor. At 100 hours of analyzer operation, the time for 90% of final response was 20 min for Hz; 8 min, MMH; and 1 min, UDMH. Interference studies showed the analyzer responding strongly to ammonia and hydrogen sulfide and less strongly to alcohols and amines. There was also interference from simulated spills of hydraulic fluid, JP-4 fuel, and ECS fluid, with relative analyzer response as high as 6 ppm MMH in the spill area. Interference and response-time problems prevent the analyzer, with the presently used liquid sensor, from being satisfactory for monitoring at or below the threshold limit values for any of the three hydrazines. The instrument is satisfactory for use as a low-ppm leak detector if precautions are taken for distinguishing between the hydrazines and interferents. (Author)