HR: 0800h
AN: OS51B-0471    [Abstracts]
TI: Hybrid Fluorometric Flow Analyzer for Underway Measurement of Ammonia in Seawater
AU: Amornthammarong, N
EM: natchanon.amornthammarong@noaa.gov
AU: * Zhang, J
EM: jia-zhong.zhang@noaa.gov
AB: A Hybrid Flow Analyzer (HFA) has been developed as a robust, highly sensitive instrument for the determination of ammonia in seawater. The instrument uses two syringe pumps to handle reagents and sample, respectively. The flow configuration is a hybrid between flow injection (FI) and sequential injection (SI) schemes. This hybrid flow analyzer spends most of its time in the continuous flow mode, providing the traditional FI advantages of baseline stability and high sensitivity while the SI mode in the remaining time provides flexibility and robustness for reagent and sample handling. The hybrid fluorometric flow analyzer has a linear dynamic range of 0-10 uM (r2 = 0.9987), with the limit of detections (3xSD) at 1 nM. The response changes by only 2.2% from 0 to 35 salinity. Moreover, the method has no refractive index effect, which is quite useful for seawater measurement. The method has been used to examine the spatial distribution of ammonia in wastewater outfalls off the coasts of Florida.
DE: 4894 Instruments, sensors, and techniques
SC: Ocean Sciences [OS]
MN: 2007 Fall Meeting