Trimethylamine , detection

In addition to their role in chemical defense, DMSP-lyase products may also function as chemical cue in more complex trophic cascades. In the natural environment DMS-production is related to zooplankton herbivory [60] and can thus act as an indicator for the availability of food for planktivorous birds. Indeed, some Antarctic Procellariiform seabirds can detect DMS (22) and are highly attracted to the cue, as was shown with DMS-scented oil slicks on the ocean surface [61]. The odors released during zooplankton grazing (DMS) as well as those of zooplankton itself (e.g., trimethylamine and pyrazines) are attractive to birds [62], thus assisting vertebrate search behavior. 

For amines absorption in an acid solution, or preferably adsorption onto an acid ion exchange column (acidified divinylbenzene-styrenesulfonic acid copolymer) is used. 10-50 1 of ambient air is sent over a wet 100 mmx 3 mm I.D. column the ion exchange polymer is put into a vial, made alkaline and the water solution is analysed on packed Carbowax-KOH GC-column with a thermionic selective detector (TSD), which is specific for nitrogen- and phosphorus-compounds. Trimethylamine is detected easily at 1 ppb. 

FIGURE I I Separation of (I) trimethylamine, (2) morpholine, (3) isopropylamine, (4) tertbutylamine, and (5) cyclohexylamine with 20 mM aminopyridine, l7mM malic acid, l7mM l8-crown-6 as BGE. The capillary was first rinsed with a polyanion solution, followed by a polycation solution to coat the capillary. Indirect UV detection at 200 nm (filter). 

Another chemical method for measuring freshness, that is more rapid, continuous, and less destructive than other methods is the detection of volatile trimethylamine (TMA), dimethylamine (DMA), monomethylamine (MMA), and ammonia 14,15). Trimethylamine oxide (TMAO) is a decomposition product of proteins as well as present in excretions of fish 16). Spoilage bacteria can reduce TMAO to TMA plus small amounts of DMA, MMA, and ammonia. Tissue TMA levels have be correlated with the pungent odor associated with spoiled seafood as well as total bacterial counts 14). Researchers incorporated a test strip... 

A1-Waiz M, Ayesh R, Mitchell SC, Idle JR, Smith RL (1989) Trimethylaminuria the detection of carriers using a trimethylamine load test. J Inherit Metab Dis 12 80-85 Al-Waiz M, Mitchell SC, Idle JR, Smith RL (1987) The relative importance of N-oxidation and N-demethylation in the metabolism of trimethylamine in man. Toxicology 43 117-121 Anonymous (1980) Workplace environmental exposure level guide. Trimethylamine. Am Ind Hyg Assoc J 41 A35-A37... 

Matsushita K, Kato K, Ohsaka A, Kanazawa M, Aizawa (1989) A simple and rapid method for detecting trimethylamine in human urine by proton NMR. Physiol Chem Phys Med NMR 21 3-4... 

Salts and organic by-products, mostly the diol resulting from hydrolysis of the epoxide, from dry cationization are left in the starch. Trimethylamine, if formed, can be detected by its odor. It can be neutralized by subsequent addition of acid. Addition of a slightly soluble organic acid, such as fumaric or adipic acid, during the cationization both eliminates the odor and aids scale control in starch cooking equipment.44... 

One of the smelliest of chemicals which the human body has to dispose of is trimethylamine, and we can detect the smell of this volatile molecule at levels of only 1 ppb. It is formed from the choline that is a... 

Although a variety of amines, particularly trimethylamine and n-butylamine have widely been used as poisons in catalytic reactions and for surface acidity determinations (20), comparably few spectroscopic data of adsorbed amines are available. As with ammonia, coordinatively adsorbed amines held by co-ordinatively unsaturated cations have preferentially been found on pure oxides (176, 193-196), whereas the protonated species were additionally observed on the surfaces of silica-aluminas and zeolites (196-199). However, protonated species have also been detected on n-butylamine adsorption on alumina (196) and trimethylamine adsorption on anatase (176) due to the high basicity of these aliphatic amines. In addition, there is some evidence for dissociative adsorption of n-butylamine (196) and trimethylamine (221) on silica-alumina. Some amines undergo chemical transformations at higher temperatures (195, 200) and aromatic amines, such as diphenylamine, have been shown to produce cation radicals on silica-alumina (201, 201a). 

The rate constants for deprotonation of the trimethylamine radical cation by the parent amine and by hydroxyl radicals were estimated as 1 x 10 and 1 x 10 M s , respectively [84]. The rate constants for the different steps involved in the reaction of oxygen with a-aminoalkyl radical 31 (Scheme 7) were determined by pulse radiolysis with conductivity detection [85]. 

Fig. 3-139. Separation of monomethylamine, dimethylamine, and trimethylamine on Vydac 400 IC 405. — Eluent 0.005 mol/L isonicotinic acid + 0.0025 mol/L HN03 + 100 mL/L methanol flow rate 2 mL/min detection direct conductivity injection volume 100 pL solute concentrations 1 ppm ammonium, 2 ppm monomethylamine, 5 ppm dimethylamine, and 10 ppm trimethylamine.

Table 3.9. Adjusted retention times for anions relative to chloride. Capacity of trimethylamine XAD-1 was 0.027 mequiv/g theoretical capacity of cetylpyridinium coated resins was 0.050 mcquiv/g. Eluent was 0.2 raM tetrabutylammonium phthalate, pH 6.5. Conductivity detection.

In a study of the decomposition of tetramethylammonium amide, Musker 107> found that the decomposition could be controlled and several products were detected when the ammonia solvent was removed at low temperature. The products isolated are those expected if the reaction proceeds via a nitrogen ylid, e.g., trimethylamine, ethylene, polymethylene, and dimethylethylamine. 

Grovenstein and Stevenson 53> reported that the reaction of the bromide salt with sodium in liquid ammonia at —33 °C gives only trimethylamine and methane with a trace of ethylene. No hydrogen gas or dimethyl-ethylamine were reported but they might have escaped detection under the experimental conditions employed. Based on product analysis, the following mechanisms were suggested in which either methyl radicals or methyl carbanions are formed. 

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