Rapid, Highly Sensitive Technique for the Determination of Ammonia in Seawater

摘要

A reliable and sensitive technique for the rapid determination of ammonia in seawater is described. The procedure is based on the conversion of ammonium ion ammonia +4 in seawater to ammonium ion ammonia 3 and the subsequent diffusion of ammonium ion ammonia 3 across a hydrophobic membrane using flow-injection analysis. Sixty determinations can be made per hour on a flowing stream of seawater or discrete samples. The lower limit of detection is 0.05 micrometers. Results of two applications that demonstrate the potential of this technique are presented, a laboratory excretion experiment employing the crab Pachygrapsus crassipes, and small-scale vertical mapping of ammonia in the ocean.