ABSTRACT
Under the conditions described for alkaline hydrolysis of reserpine and rescinnamine in absolute and aqueous methanol, and after esterification (with diazomethane) of the resulting acid fraction, methyl 3,4,5-trimethoxybenzoate was quantitatively recovered, whereas methyl trans-3,4,5-trimethoxycinnamate, in normal lighting conditions, was either partly isomerized to methyl cis-trimethoxycinnamate or formed an adduct with a molecule of methanol, yielding methyl 3-methoxy-3-(3,4,5-trimethoxyphenyl)propionate. The structures of the products were established by synthesis, nuclear magnetic resonance studies and mass spectrometry. This investigation of the hydrolytic conditions allowed a reliable and rapid gas chromatographic determination of reserpine and/or rescinnamine in amounts down to 500 and 2000 mug, respectively, to be devised.
Subject(s)
Chromatography, Gas , Reserpine/analogs & derivatives , Reserpine/analysis , Hydrogen-Ion Concentration , Hydrolysis , Magnetic Resonance Spectroscopy , Mass Spectrometry , Methods , MicrochemistryABSTRACT
A method is described through which acetate ion in cosmetics is determined, in order to establish lead diacetate contents. Lead, from sample aqueous solutions is precipitated by 1 M oxalic acid and the resulting free acetic acid is determined via GLC, using propionic acid as internal standard. The lead neutral acetate contents resulting either from gas-chromatographic or lead titrimetric determinations are in good agreement. A typical gas-chromatogram is also reported.