Determination of antitubercular drugs by micellar electrokinetic capillary chromatography (MEKC)

A method for the determination of isoniazid (ISO), pyrazinamide (PYR) and rifampicin (RIF) in pharmaceutical products, by micellar electrokinetic capillary chromatography (MEKC) with ultraviolet detection is described. The influence of pH, concentration of surfactants, buffer and organic solvents, over the separation were studied as experimental variables. The optimal separation was carried out at 30 degrees C and 20 kV, using a 40 mM borate buffer and 100 mM sodium dodecylsulphate (SDS) adjusted to pH 8.5. Under these conditions, the analysis is accomplished in about 8 min. The method was applied to the determination of these compounds in different pharmaceuticals with good results when compared with a reference liquid chromatographic (LC) method.

Simultaneous determination of flavor enhancers inosine 5'-monophosphate and guanosine 5'-monophosphate in food preparations by derivative spectrophotometry

A derivative spectrophotometric method was developed for the quantitative determination of 2 flavor enhancers, inosine 5'-monophosphate (IMP) and guanosine 5'-monophosphate (GMP), in the presence of monosodium glutamate (MSG). Procedures for determining IMP and GMP singly and in binary mixtures are described. Overlapping absorption spectra of both compounds were resolved by using first-derivative spectrophotometry. By measuring the first-derivative signals of IMP and GMP at 253 and 248 nm, respectively, simultaneous determination was possible for IMP and GMP at 5-40 micrograms/mL, in the presence of up to 5000 micrograms/mL MSG. The method was satisfactorily used to determine IMP and GMP in several food preparations.