Ammonia detection

Timmer, B.H., van Delft, K.M., Otjes, R.P., Olthuis, W., Bergveld, P., van den Berg, A., Towards a miniaturized ambient ammonia detection system. Micro Total Analysis Systems 2003, Proceedings 7th flTAS Symposium, Squaw Valley, CA, Oct. 5-9, 2003, 81-84. 

Nitrate in the presence of bromide and iodide The brown ring test for nitrates cannot be applied in the presence of bromides and iodides since the liberation of the free halogen with concentrated sulphuric acid will obscure the brown ring due to the nitrate. The solution is therefore boiled with sodium hydroxide solution until ammonium salts, if present, are completely decomposed powdered Devarda s alloy or aluminium powder (or wire) is then added and the solution gently warmed. The evolution of ammonia, detected by its smell and its action upon mercury(I) nitrate paper (see Section III.38, reaction 1) and upon red litmus paper, indicates the presence of a nitrate. 

Test for ammonium ions Boil a little (c. 0 1 g) of the substance with sodium hydroxide solution. The evolution of ammonia, detected by its odour and its action upon red litmus paper and upon filter paper soaked in mercury nitrate solution, indicates the presence of an ammonium salt. 

The dabsyl derivatives of ammonia and methylamine are separated from other reaction components by chromatography an Altex Ultrasphere-ODS Cjs column (4.6 mm X 150 mm, 5 /im). An anion guard column from Bio-Rad (Anion-SA, sulfate form, 4.6 mm X 40 mm) was placed ahead of the main column. For ammonia detection only, an Altex Ultrasphere-ODS column... 

The disadvantage are toxicity and flammability. Ammonia has a corrosive effect on tissues and can cause laryngeal, bronchial spasm and edema, which lead to obstructed breathing. Ammonia s flammability range in air is 16-25% by volume. It is usually characterized as hard to ignite (71). A suitable ammonia detection system with alarm should be installed and well maintained. Detectors should sound an alarm at the lowest practical level, not to exceed 1000 ppm. 

The basic ammonia detection test has always been The sense of smell. The odor of ammonia must be completely gone from The compost before it can be spawned. Odors are always good indicators of compost suitability. However, to be absolutely certain, other methods are also used. 

NS-Ti02 materials have been used for ammonia detection [277-280]. Suh etal. [277] proposed a thin film gas sensor planar structure of fabricated with Ti02 to monitor ammonia. They deposited a thin sensitive Ti02 film by a DC reactive magnetron sputtering technique onto a cleaned silicon substrate equipped with interdigitated comb shaped... 

Polyhydric alcohols react with HIO4 to yield iodate which is precipitated with silver nitrate, and the precipitation is dissolved in ammonia. Detection limits for glycerol, lactose, and glucose are 0.16, 0.82, and 0.28 mg, respectively. 

Detactor tubes—are probably, the simplest (and least accurate) of the direct reading instruments. The detector tubes are often referred to by the name of their manufacturer, such as Drager or Sensidyne tubes. The detector tube is hermetically sealed at both ends and filled with a granular or powdery reagent. Each tube is specific for a particular gas or vapor, hence tubes for ammonia detection are different from the tubes for carbon monoxide or methane detection. Each tube has printed on it s surface the name of the chemical it is specifically designed to test for. 

Huang J, Wang J, Gu C, Yu K, Meng F, Liu J. A novel highly sensitive gas ionization sensor for ammonia detection. Sens Actuators, A Phys 2009 150 218-23. 

Flow-through chemiresistors. Sens Actuators B 162 400-408 He L, Jia Y, Meng F, Li M, Liu J (2009) Gas sensors for ammonia detection based on polyanUine coated multiwall carbon nanotubes. Mater Sci Eng B 163 76-81... 

Oprea A, Simon E, Fleischer M, Frerichs H-P, Wilbertz C, Lehmann M, Weimar U (2005) Flip-chip suspended gate field effect transistors for ammonia detection. Sens Actuators B 111 582-586 Ostrick B, Mlihlsteff J, Fleischer M, Meixner H, DoU T, Kohl C-D (1999) Adsorbed water as key to room temperature gas sensitive reactions in work function type sensors the carbonate-carbon dioxide system. Sens Actuators B 57 115-119 Ostrick B, Fleischer M, Meixner H, Kohl C-D (2000a) Investigation of the reaction mechanisms, in work function type gas sensors at room temperature by studies of the cross sensitivity to oxygen and water the carbonate-carbon dioxide system. Sens Actuators B 68 197-202... 

Room temperature chemical sensors for alcohol, acetone, water vapor and ammonia detection were developed [1,2] by using beta alumina and xerogel of antimonic acid hydrate. The sensitivity and selectivity depend on ion-exchange and preparative methods. Ammonia-exchanged samples of beta alumina were sensitive to water and ammonia vapor. Potentiometric and amperometric sensors are made by using ion conducting material as the substrate, an Au electrode as the reference and Pd (or Ag, Ni, Pt) as the sensitive electrode. 

As a further safety dimension an ammonia detection system in an area around the storage facility may be used. Such a system would give indications of any leaks from the ammonia storage and record even a few ppm of ammonia in the atmosphere [85]. The knowledge learned on stress corrosion cracking, construction, safe operation, and maintenance has contributed greatly to the safety of atmospheric ammonia storage systems. 

It should be mentioned that the dopants can also participate in reactions with a gas acrylic acid-doped PANI (PANI-AA)-based chemiresistors recorded decreases in resistance upon exposure to ammonia. In fact, these sensors demonstrated a high sensitivity toward ammonia (detection of 1 ppm was possible) with a linear increase in resistivity upon changes in gas concentration. The authors su ested that the response is attributable to proton removal from acrylic add dopants by ammonia molecules, thereby increasing charge density in the PANI. 

Manne J (2006) Pulsed quantum cascade laser-based cavity ring-down spectroscopy for ammonia detection in breath. Appl Optics 45 9230-9237... 

Li C, Zhu S, Ding Y, Song Q (2012) Electrochemiluniescence of iridinm complexes with ammonia in dimethylformamide and its analytical application for ammonia detection. J Electroanal Chem 682 136-140... 

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