Separation and identification of various vulcanization agents and antioxidants in two types of rubber by chromatographic and spectrometric methods.
The aim of this study was to separate and identify by chromatographic and spectrometric methods, the various allergenic vulcanization agents and antioxidants used in the manufacture of industrial rubber. Specimens of elastomers were manufactured specially for this study. The specificity of the gas chromatographic method developed allows separation of all the manufacturing additives in the selected rubber types after one injection only, even though they belong to extremely varied chemical categories. The GLC method was coupled with mass spectrometry, which permitted identification of the peaks obtained and the study of the fragmentation of the 4 reference products under various conditions. Separation by TLC was performed in parallel on the same extracts, allowing rapid identification of the products tested for, and showed new spots after vulcanization.
Chromatographic analysis of elastomer antidegradants and accelerators
Summary The use of various chromatographic methods in the analysis of all classes of elastomer antidegradants and accelerators is reviewed. The review of extraction methods is also included.
Inhibitors of monoamine oxidase. Influence of methyl substitution on the inhibitory activity of beta-carbolines.
A number of tetrahydro and aromatic β -carbolines, mostly with a methyl substituent at various positions, were synthesized and their in vitro inhibitory activities on monoamine oxidase evaluated. Substitution of a methyl group at the N-9 nitrogen of tetrahydro- β -carboline gave a potent competitive inhibitor of the enzyme. Methyl groups at C-1 of both tetrahydro and aromatic β -carbolines generally reduced the potency, whereas introduction of a methyl group at the N-2 nitrogen of tetrahydro- β -carboline gave a compound of equal activity.