A Novel Optoelectronic Detector and Improved Flow Analysis Procedure for Ammonia Determination with Nessler’s Reagent

Abstract

This paper presents a simple, rapid and effective method for ammonia determination in a flow analysis regime using Nessler's reagent. The proposed modification of the common flow procedure results in the total elimination of the problem of precipitate deposition inside the flow manifold. The improved procedure has been adapted to a flow analysis system based on microsolenoid pumps combined with a dedicated optoelectronic detector fabricated specifically for this purpose. This photometric device has been constructed in the form of a compact flow-through cell (70 μL total volume and 1 cm optical pathlength) integrated with 395 nm LED emitter and 405 nm LED-based detector. The presented analytical system is capable of ammonia determination in the submillimolar concentration range with a detection limit below 0.1 mM and high throughput (over 20 injections per hour).

Variations in microbial community structure and functional gene expression in bio-treatment processes with odorous pollutants

“…The odor index was defined using a series of formula described by Noguchi’s work 21 . The NH 3 concentrations were measured using the Nessler’s reagent colorimetry method 22 . The H 2 S concentrations were measured using the methylene blue spectrophometry method (GB/T11742-89, China).…”

Metagenomic analysis of microbial community structure and function in a improved biofilter with odorous gases

“…For NH 3 , the initial concentration is 9.3 mg.m − 3 and the emission rate is about 0.2 kg.h − 1 . The NH 3 concentration was determined using the Nessler's reagent colorimetry method [28]. The H 2 S concentration was determined using the methylene blue spectrophometry method (GB/T11742-89, China).…”

Sampling and analysis of airborne ammonia in workplaces of China

“…The final pH of Nessler reagent is 12.4 ± 0.1 at 25°C. 14,15 Under alkaline conditions, the iodide and mercury ions in Nessler reagent can react with ammonia to form deeper yellow complex, which has a maximum absorption at the wavelength of 420 nm. 11 The absorbance is proportional to the content of ammonia-nitrogen in the reaction system.…”

“…Nessler reagent is an alkaline solution of potassium tetraiodomercurate (K 2 HgI 4 ) prepared by potassium iodide, mercuric chloride, and sodium/potassium hydroxide. The final pH of Nessler reagent is 12.4 ± 0.1 at 25°C . Under alkaline conditions, the iodide and mercury ions in Nessler reagent can react with ammonia to form deeper yellow complex, which has a maximum absorption at the wavelength of 420 nm .…”