Nicotinic acid volatile acidity

In MALDI, the sample is embedded in a non-volatile matrix such as nicotinic acid or 2,5-dihydroxybenzoic acid. The sample matrix is introduced into the mass spectrometer, charged to high-voltage and exposed to a high-energy laser beam. The matrix material is chosen to absorb the laser radiation and the radiation causes the matrix and sample molecules to vaporise or sputter into the gas phase. 

The first mention of the presence of pyridine in roasted coffee was made by Monari and Scoccianti (1895), but 18 years later Bertrand and Weisweiller (1913) continued to ignore this discovery. Hughes and Smith (1946) published an interesting study on the non-volatile nicotinic acid, but it was only after the advent of gas chromatography that the number of identifications increased, as was the case for many other classes of compounds. The main contributions were due to Vitzthum and Werkhoff (1974b) and Baltes and Bochmann (1987d,e). 

Viani and Horman (1974, 1976) (who also quoted Teply et al, 1945) identified nicotinic acid in the non-volatile fraction of the thermal fragmentation of trigonelline (see Section 2.1.1.2). 

B.p. 195-6°/753 mm. (179°), 76°/12 mm. D 0-9656. Sol. EtOH, EtjO. Spar. sol. HjO. Volatile in steam. Cold KMnOg — 4-methyl-pyridin0-3-carboxylic acid -f pyridine-3 4- -carboxylic acid. Hot KMnOg — nicotinic acid. Na + EtOH —> 4-methyl-3-ethylpiperidine. B,HCl hygroscopic plates. 

Nicotinamide and nicotinic acid are insulHciently volatile to be analyzed directly by GC. However, after suitable derivatization their GC analysis becomes feasible. 

D is a volatile base, CgH N, b.p. 134-8°, DJF 0-9595, nj, ° 1-4968, giving a picrate, m.p. 154-6°, and a mercurichloride, m.p. 151-2° it is isomeric with the picolines and resembles j8-picoline, but does not oxidise to nicotinic acid or reduce to j3-pipecoline and so cannot be j8-picoline j it may contain some a-picoline. A base similar to D has been isolated from tell fescue grass. ... 

When roasting coffee, the caffeine content is virtually unchanged. TrigoneUine that accompanies coffee alkaloids decomposes to nicotinic acid and volatile sensorially active pyridines, therefore the trigonelline and caffeine contents ratio is used as an indicator of coffee roasting intensity. 

Honey consists chiefly of dextrose and levu-lose (70-80%) with smaller amount of water, sucrose (2-10%), dextrin, wax, proteins, volatile oil, minerals, acids, and coloring and flavoring components, based on derivative plant source contains vitamin Bi, vitamin B2, vitamin C, nicotinic acid, and formic acid (csiR i martestdale). 

These nicotinoids are appreciably volatile (nicotine vapor pressure, 5.7 Pa at 25°C) and, although colorless Hquids when pure, rapidly darken upon exposure to air. They are highly basic = 1 x 10 , = 1 x 10 ) and readily form salts with acids and many metals. Nicotine sulfate [65-30-5],... 

The acid-base chemistry of nicotine is now well known and investigations have shown that nicotine in tobacco smoke or in smokeless tobacco prodncts can exist in pH-dependent protonated or nnprotonated free-base forms. In tobacco smoke, only the free-base form can volatilize readily from the smoke particnlate matter to the gas phase, with rapid deposition in the respiratory tract. Using volatility-based analytical measurements, the fraction of nicotine present as the free-base form can be quantitatively determined. For smokeless tobacco products, the situation differs because the tobacco is placed directly in the oral cavity. Hence, the pH of smokeless tobacco prodncts can be measured directly to yield information on the fraction of nicotine available in the nnprotonated free-base form. It is important to characterize the fraction of total nicotine in its conjugate acid-base states as this dramatically affects nicotine bioavailability, because the protonated form is hydrophilic while the nnprotonated free-base form is lipophilic and thus readily diffuses across membranes (Armitage and Turner 1970 Schievelbein et al. 1973). As drug delivery rate and addiction potential are linked (Henningfield and Keenan 1993), increases in delivery rate due to increased free-base levels affect the addiction potential. 

Tobacco smoke contains more than 3800 different compounds. About 10% of these constimte the particulate phase, which contains nicotine and tar. The remaining 90% contains volatile substances such as carbon monoxide, carbon dioxide, cyanides, various hydrocarbons, aldehydes, and organic acids. Although all of these substances affect the smoker to some degree, nicotine is generally considered to be the primary substance responsible for the pharmacological responses to smoking (Nielsen et al. 2001). 

Salicylic acid 11.49 is another signaling molecule in the plant s response. The amount of jasmonic acid rises in 5 min after the insect begins feeding on the tobacco plant. The acid reaches the roots in 2 h and a flush of nicotine reaches the leaves (up to 120 mg/g leaf) in 7 h. Both of these acids can trigger the release of volatile compounds from the plant. These include not only terpenes, but also methyl jasmonate and methyl salicylate, which can signal nearby plants to mount their defenses against attack.183 Methyl jasmonate also inhibits the sprouting of potatoes.184... 

A new photometric determination of volatile bases in tobacco and tobacco smoke in terms of nicotine, which compares quantitatively with mass spectral and g.c. methods, has been developed.27 A colorimetric method for the estimation of nicotine alkaloids in tobacco by reaction with cyanogen bromide and 4,4 -di-aminostilbene-2,2 -disulphonic acid has also been reported.28 Dilute sulphuric acid extraction of nicotine and anabasine from autopsy tissue appears to be a more efficient method than extraction with acidified ethanol, aqueous oxalic acid, and steam distillation.29 Thin-layer chromatography has been effective in the analysis of nicotine and other alkaloids and drugs.30 Two reports on the isolation of anabasine from anabasine-lupinine mixtures have appeared.31 The P a values of some nicotine-type compounds have been determined.32... 

Sparteine. An alkaloid obtained from broom, also a volatile, oily liquid. Conine, nicotine, and sparteine ore similar in character, being very poisonous, possessing strong alkaline reaction, and forming crystal-lizable salts with the acids,... 

These may be isolated by steam distillation. It is usual to make two such distillations, the first from acid solution, the second from alkaline. About 50-100 gm of tissue is homogenized, mixed with an equal quantity of water, acidified with tartaric acid and steam-distilled until a volume ecpial to the original sample taken has been collected. This distillate will contain neutral and acidic compounds such as hydrocyanic acid, phenol, and phosphorus. The tissue slurry is now made alkaline with sodium hydroxide solution and again subjected to steam distillation. This second distillate will contain basic compounds. The tip of the condenser should be immersed in dilute hydrochloric acid to trap the more volatile bases. The plant alkaloids most likely to be present are nicotine, coniine, arecoline, ephedrine, and sparteine, but a number of synthetic drugs, notably amjihetamine and other sympathomimetic bases, also occur in this fraction. Pethidine may also be isolated by steam distillation. The... 

Protein and free amino acids found in tobacco leaf contribute significantly through pyrodegradation and pyrosynthesis to the formation of many nitrogenous compounds found in tobacco smoke. The nonvolatility of these compounds either as free acids, proteins, or members of tobacco pigment, for example, porphyrins, make them particularly liable to pyrolytic destruction because they, unlike nicotine and the other plant alkaloids, are not readily volatilized and swept away as the more intense heat of the cigarette coal approaches (3724). 

In a burning cigarette during actual smoking, a substantial portion of the nicotine (about 41%) remains intact, 12.5% is oxidized to carbon dioxide, as much as 11% is degraded to volatile alkylpyridines, and negligible amounts are converted to neutral or acidic components of the particulate phase. 

Precursors of NNAs in both tobacco and tobacco smoke are the proteins and amino acids (plus nitrate) for the volatile NNAs [Bmnnemann etal. (481, 482), Hoffmann etal. (1694)] and nicotine and nicotine-related alkaloids (plus nitrate) for the TSNAs [Boyland etal. (422, 423), Rathkamp etal. (3080), Hecht etal. (1563,1565)]. The levels of NNAs in tobacco and its smoke parallel the tobacco nitrate level [Morie and Sloan (2635), Hecht etal. (1576,1578), Tsoetal. (3985)]. 

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