Pure compounds solubility tests

All compounds are tested as purified active ingredients. Most compounds are obtained from commercial sources, some are purified at Cerep from a formulated product, and some have been synthesized at Cerep. The purity (chromatographic purity) is measured by the aqueous solubility assay, which uses LC/MS with UV or evaporative light scattering detection to analyze the sample. More than 99% of BioPrint compoimds are >95% pure. The remaining compounds are >80% pure and are primarily compounds purified from natural extracts. 

In solubility tests of the pure compounds in distilled and cement-equilibrated water, iodate concentrations in both liquids were near the expected theoretical values for 68(103)2 and Ca(I03)2 For (103)2 the concentration in distilled water corresponded to the expected value however, the concentration in the cement-water was a factor of 1000 higher. This higher concentration was attributed to hydrolysis due to the high pH ( 12) of the cement-water. Hydrolysis would account for the release of iodine from the Hg(IO3)2-cement. The iodate concentrations found in the leachates of the cements containing 68(103)2 and Ca(I03)2 were a factor of 10 lower than expected. No metallic ion concentration was sufficiently high to cause precipitation of the iodate. 

In any attempt to determine the structure of an unknown biological compound, researchers must deal with two fundamental problems (1) If you don t know what it is, how do you know if it is pure (2) If you don t know what it is, how do you know that your extraction and purification conditions have not changed its structure Morgan addressed problem 1 through several methods. One method is described in his paper as observing constant analytical values after fractional solubility tests (p. 312). In this case, analytical values are measurements of chemical composition, melting point, and so forth. 

The extraction tests were exploratory and arbitrary in nature for two reasons relatively little plant material was supplied, with the result that no optimization studies could be carried out and pure material was unavailable for solubility testing. Not only were optimization studies impossible but also the extraction conditions were selected from experience with other complex organic compounds. 

The tests of solubility are of course carried out with chemically pure compounds. Examples of the solubility of typical representatives of the given classes of compounds are shown in Table 2, where compounds of intermediary character, i.e., the positions of which are on the boundaries of individual solubility classes, are also listed (1). 

Solubility in concentrated sulphuric acid. Place 3 0 ml. of pure concentrated sulphuric acid in a dry test-tube and add 0 -10 g. of a solid or 0 -20 ml. of a liquid. If the compound does not dissolve immediately, agitate for some time but do not heat. Observe any change in colour, charring, evolution of gaseous products, polymerisation accompanied by precipitation etc. 

There are indications that pure naphthalene (a constituent of mothballs, which are, by definition, toxic to moths) and alkylnaphthalenes are from three to 10 times more toxic to test animals than are benzene and alkylbenzenes. In addition, and because of the low water solubility of tricyclic and polycyclic (polynuclear) aromatic hydrocarbons (i.e., those aromatic hydrocarbons heavier than naphthalene), these compounds are generally present at very low concentrations in the water-soluble fraction of oil. Therefore, the results of this smdy and others conclude that the soluble aromatics of crude oil (such as benzene, toluene, ethylbenzene, xylenes, and naphthalenes) produce the majority of its toxic effects in the enviromnent. 

Solubility screens using LC/MS detection do not require an ultra-pure sample of the test compound due to the selective detection of the mass spectrometer. Mass spectrometric detection offers high selectivity and low detection limits, which eliminates the need to develop complex chromatographic methods. The LC/MS-based solubility screen surpasses the traditional HPLC/UV-based equilibrium solubility assay with increased throughput, minimal manual intervention, and high sensitivity and selectivity. 

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