Determination of ammonium- and nitrate-nitrogen by molecular emission cavity analysis

Abstract

Ammonium nitrogen is determined a t parts per million to percentage levels by injecting the sample solution on to solid sodium hydroxide in a small vial. The ammonia generated is swept by nitrogen into a molecular emission cavity analysis (MECA) oxy-cavity and the intensity of the NO-0 continuum is measured a t 500 nm. The method is rapid, precise and free from interferences and has b z n applied successfully to the determination of ammonium ions in fertilisers, river waters and sEwage samples. Nitrate ions can also be determined after reduction to ammonia by Devarda's alloy.

Development of Colorimetric and Ratiometric Fluorescence Membranes for Detection of Nitrate in the Presence of Aluminum-Containing Compounds

“…Ammonia could be produced through the reductive reaction of nitrate by the presence of Devarda’s alloy in alkaline solution as shown in Equation (2) [ 14 , 15 ], 3NO 3 − + 8Al + 5OH − + 18H 2 O → 3NH 3 + 8[Al(OH) 4 ] − …”

“…As another approach for nitrate detection, nitrate can be reduced to ammonia through reducing reagents, such as Devarda’s alloy [ 14 , 15 ] and zinc [ 16 ], and subsequently the produced ammonia is determined by typical methods [ 14 , 15 , 16 ]. In this approach, the reduction step of nitrate to ammonia is not complicated, but the detection method for ammonia is very important to obtain a wide linear detection range and a low limit of detection.…”

“…In this approach, the reduction step of nitrate to ammonia is not complicated, but the detection method for ammonia is very important to obtain a wide linear detection range and a low limit of detection. Belcher et al [ 15 ] use a technique called molecular emission cavity analysis (MECA) for ammonium nitrogen detection. This technique is rapid, precise, and free of interference, as it uses a hydrogen-based flame for generating molecular emission, and obtains a wide range of detection of nitrate, that is, 0.7–28.5 mM with an LOD of 70 µM.…”

Metals in River Water

“…Molar-emission cavity analysis has been applied 80 to the determination of ammonium (and nitrate) nitrogen in river water samples. The water sample is injected onto solid sodium hydroxide in a small vial.…”

High-resolution continuum source molecular absorption spectrometry of nitrogen monoxide and its application for the determination of nitrate

“…Nitrogen also tends to form very stable small molecules, such as N 2 , CN, NH and NO. Therefore, apart from a few exceptions, 14 spectrometric methods for the nitrogen determination are predominantly based on the determination via emission [15][16][17][18][19] or mass 19 spectra of small, N-containing molecules instead of their atomic spectra.…”