Identification of new impurities of enalapril maleate on oxidation in the presence of magnesium monoperoxyphthalate.

Stress stability testing and forced degradation were used to determine the stability of enalapril maleate (EM) and to find a degradation pathway for the drug. The degradation impurities, formed under different stressed conditions, were investigated by HPLC and UPLC-MS methods. HPLC analysis showed several degradation impurities of which several were already determined, but on oxidation in the presence of magnesium monoperoxyphthalate (MMPP) several impurities of EM were observed which were not yet characterized.

Identification of gentamicin impurities by liquid chromatography tandem mass spectrometry.

An HPLC/MS/MS method was developed for identification of impurities in gentamicin. The HPLC was performed on a Synergy Hydro-RP column using 50 mM trifluoroacetic acid (TFA), pH 2 adjusted with ammonium solution and methanol as mobile phase. All impurities in gentamicin were separated from main gentamicin components.

Self-crosslinking and film formation ability of liquefied black poplar.

Black poplar wood, diethylene glycol (DEG), and sulphuric acid as a catalyst were used as starting reactants for liquefaction. Optimal conditions for liquefaction were established: reaction temperature 150 degrees C, reaction time 95min, ratio of wood:DEG=1:5 and 3% of sulphuric acid addition. The liquid mixture obtained by the liquefaction was composed of the real product of the reaction (the so called "excess solvent free liquefied wood" (ESFLW)) and of the remaining unreacted DEG.

Optimisation of programmable temperature vaporizer-based large volume injection for determination of pesticide residues in fruits and vegetables using gas chromatography-mass spectrometry.

The applicability of programmable temperature vaporizer (PTV) solvent vent injection to the gas chromatographic (GC) determination of pesticide residues in fruits and vegetables was evaluated with the aim of miniaturizing the current multiresidue method. For that purpose 24 pesticides representing different chemical classes were initially chosen for optimisation of the large volume injection (LVI) parameters. Various parameters related to the optimum injector performance were tested for several types of packed and empty liners using both fast (at-once) and speed-controlled PTV solvent vent injection of standard solutions in ethyl acetate.

Determination of serum lysophosphatidic acid as a potential biomarker for ovarian cancer.

A fast and selective analytical method, used to determine the different lysophosphatidic acid (LPA) species in serum, has been developed and validated. LPA species were quantitatively extracted from serum using methanol-chloroform (2:1, v/v). The proteins were precipitated by this solvent mixture and separated by centrifugation in one step.