A submersible battery-powered flow injection (FI) sensor for the determination of nitrate in estuarine and coastal waters

Abstract

T he design, construction and perf ormance of a remotely deployed sub mersible¯ow injection-based nutrient ( total oxidized nitrogen) sensor are described. T he sensor f eatured a custom-b uilt microcomputer and a solid-state,¯ow -through spectrophotometric detector, and the derivatization chemistry w as based on in-line copper± cadmium reduction of nitrate to nitrite, and diaz otiz ation w ith N 1N E D and sulphanilamide. T he limit of detection w as 0.0014 mg l 1 N O 3 ± N and the linear range w as 0.0014± 0.77 mg l 1 w ith a 260 ¹l sample volume and a 20 mm path length¯ow cell. R esults f rom sub mersed deployments in the T amar estuary and N orth S ea are also reported. J ournal of A utom ated M ethods & M anagement in C hemistry, V ol. 21, N o. 1 (J anuary ± F ebr uary 1999) pp. 1 ± 9

Flow injection analysis as a tool for enhancing oceanographic nutrient measurements—A review

“…diazotization with sulfanilamide followed by coupling with N-(1-naphthyl)-ethylenediamine dihydrochloride (NED) to form a pink azo dye [125]. Johnson and Petty [126] first described the use of FIA for nitrate measurement in marine waters using Cd reduction and the Griess reaction for nitrite detection, and their work has been adapted by many for surface [127] and submersible systems [27,[128][129][130][131].…”

“…in tethered buoys, as described by Répécaud et al [240]. There has been limited, but continuing development of FIA in submersible systems and on remotely operated vehicles (ROVs) [128][129][130][131]180,[241][242][243][244][245][246], and there is great potential in this area, given the developments in microfluidic devices during the last decade. The microfluidic flow device described by Beaton et al for the determination of nitrate [247] is an example of the new generation of flow analysis devices under development.…”

A portable flow-injection instrument incorporating a miniature spectrometer for the real-time monitoring of nitrate in rivers

“…The copperized cadmium was then washed with 2 M hydrochloric acid and then a 10 g L ‫1מ‬ ammonium chloride solution and packed into an in-house designed acrylic column [3] (10 mm o.d. The carrier stream was prepared by dissolving ammonium chloride (10 g) in 1 L of water.…”