A personal ammonia monitor utilizing permeation sampling.
Benedict-AF; Reiszner-KD; West-PW
Am Ind Hyg Assoc J 1983 Jan; 44(1):66-70
A newly developed personal ammonia (7664417) monitor was described. The monitor consisted of a 41 millimeter outside diameter glass tube sealed at one end with a 3 mil loops/up knit backed supported silicone membrane and at the other with Saran Wrap. The tube was filled with 10 milliliters of boric-acid at a concentration of 3 grams per 500 milliliters. During operation, ammonia permeated through the silicone membrane into the boric-acid solution. The trapped ammonia was then determined spectrophotometrically with Nessler's reagent or potentiometrically with an ion selective electrode. The detection limit was 0.4 parts per million (ppm) for 8 hours sampling, with precision better than 5 percent. The monitor responded linearly to ammonia concentrations up to at least 150ppm. When tested over a temperature range of 0 to 50 degrees-C, the collection rate increased by only 0.57 percent per 1 degree increase. Humidity had only a slight effect on collection efficiency, the maximum difference being only 4 percent for 0 to 95 percent relative humidity. Potential interferences from monoethanolamine and ethylenediamine were investigated. Samples containing up to 2024 micrograms monoethanolamine caused only an 8 percent deviation when ammonia was determined with Nessler's reagent. Ethylenediamine formed a milky solution with Nessler's reagent; however, it caused generally only small deviations when the ion selective technique was used. The authors conclude that the ammonia monitor is accurate, reliable, and reproducible and is not affected by environmental factors normally found in industrial locations. The monitor provides a relatively inexpensive technique for occupational monitoring.
NIOSH-Publication; NIOSH-Grant; Nitrogen-compounds; Analytical-methods; Laboratory-testing; Air-sampling; Environmental-factors; Electrochemical-analysis; Absorption-spectrophotometry; Reagents; Equipment-design
Chemistry Louisiana State Univ A&M Coll 111 Coates Laboratories Baton Rouge, LA 70803
American Industrial Hygiene Association Journal
Louisiana State Univ A&M Col Baton Rouge, Baton Rouge, Louisiana