Quinin

In the following decades, chemists tried to utilize more and more the knowledge on reactions which had already been gained. A number of landmark syntheses represent the change to modern chemistry, such as the synthesis of the estrogenic steroid equilenin (W. Bachmann, 1939), of pyridoxine (K. Folkers, 1939), and of quinine (R.B. Woodward, W. von E. Doering, 1944) [23]. 

Supplement (combined with Volumes XXIV and 1936 3458-3793 methane, 25. Pyrimidine, 89. Pyrazine, 91. Nicotine, 110. Dipyridyl, 199. Phenanthroline, 227. Hydroxy compounds, 348 Cinchonine, 424. Quinine, 511. Indigo white, i... 

Many alkaloids such as nicotine and quinine contain two (or more) nitrogen atoms The nitrogens... 

Acridine orange hydrochloride Ethanol 0.54 Quinine sulfate 0.58 Anthracene... 

Fluorescein, ethyl ester O.lNNaOH 0.99 Quinine sulfate 0.99 POPOP... 

Thymol Acetanilide, antipyrine, camphor, chlorohydrate, menthol, quinine sulfate, ure-thene... 

Description of Method. Quinine is an alkaloid used in treating malaria (it also is found in tonic water). It is a strongly fluorescent compound in dilute solutions of H2SO4 (f = 0.55). The excitation spectrum of quinine shows two absorption bands at 250 nm and 350 nm, and the emission spectrum shows a single emission band at 450 nm. Quinine is rapidly excreted from the body in urine and is easily determined by fluorescence following its extraction from the urine sample. 

Chloride ion is known to quench the intensity of quinine s fluorescent emission. For example, the presence of 100 ppm NaCI (61 ppm Ch) gives an emission intensity that is only 83% of that without chloride, whereas the presence of 1000 ppm NaCI (610 ppm Ch) gives a fluorescent emission that is only 29% as intense. The concentration of chloride in urine typically ranges from 4600 to 6700 ppm Ch. Flow is an interference from chloride avoided in this procedure ... 

Extracting the aqueous urine sample with a mixture of chloroform and isopropanol separates the quinine and chloride, with the chloride remaining in the urine sample. 

Samples of urine that do not contain quinine still contain a small amount of fluorescent material after the extraction steps. Flow can the quantitative procedure described earlier be modified to take this into account ... 

One approach is to prepare a sample blank using urine known to be free of quinine. The fluorescent signal for the sample blank is subtracted from the urine sample s measured fluorescence. 

The fluorescent emission for quinine at 450 nm can be induced using an excitation frequency of either 250 nm or 350 nm. The fluorescent quantum efficiency is known to be the same for either excitation wavelength, and the UV absorption spectrum shows that 250 is greater than 350- Nevertheless, fluorescent emission intensity is greater when using 350 nm as the excitation wavelength. Speculate on why this is the case. 

With the introduction of improved analytical techniques, starting around 1817, the evaluation of dmgs began and, over a span of about 10 years, strychnine (13, R = H), emetine (14), bmcine (13, R = OCH3), piperine (15), caffeine (16), quinine (17, R = OCH3), colchicine (4), cinchonidine (17,... 

A persistent idea is that there is a very small number of flavor quaUties or characteristics, called primaries, each detected by a different kind of receptor site in the sensory organ. It is thought that each of these primary sites can be excited independently but that some chemicals can react with more than one site producing the perception of several flavor quaUties simultaneously (12). Sweet, sour, salty, bitter, and umami quaUties are generally accepted as five of the primaries for taste sucrose, hydrochloric acid, sodium chloride, quinine, and glutamate, respectively, are compounds that have these primary tastes. Sucrose is only sweet, quinine is only bitter, etc saccharin, however, is slightly bitter as well as sweet and its Stevens law exponent is 0.8, between that for purely sweet (1.5) and purely bitter (0.6) compounds (34). There is evidence that all compounds with the same primary taste characteristic have the same psychophysical exponent even though they may have different threshold values (24). The flavor of a complex food can be described as a combination of a smaller number of flavor primaries, each with an associated intensity. A flavor may be described as a vector in which the primaries make up the coordinates of the flavor space. 

Fig. 1. Quinine knines from primary intermediates couple with secondary intermediates to form viscous colors.

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