Alexey V. Shpak

Noninvasive detection of counterfeited ampoules of dexamethasone using NIR with confirmation by HPLC-DAD-MS and CE-UV methods

Application of near-infrared (NIR) measurements together with chemometric data processing is widely used for counterfeit drug detection. The most difficult counterfeits to detect are the “high quality fakes”, which have the proper composition but are produced in violation of technological regulations by underground manufacturers. This study uses such forgeries and addresses important issues. The first is the possibility of applying the NIR/chemometric approach to the detection of injectable formulations of drugs (in this case dexamethasone), which are aqueous solutions with low concentration of active ingredients, directly in the closed ampoules. The second issue is the comparison of NIR/chemometric conclusions with detailed chemical analysis.

1-Formyl-2,2-dimethylhydrazine as a new decomposition product of 1,1-dimethylhydrazine

A new decomposition product of 1,1-dimethylhydrazine (UDMH), 1-formyl-2,2-dimethylhydrazine (FDMH), was found in water and soil samples. The formation of FDMH was confirmed by LC-MS and NMR studies. The possibility of FDMH conversion to initial UDMH by alkaline hydrolysis was shown.

Ion-chromatographic determination of the constant of ion exchange of aliphatic hydrazines and amines on silica-gel-based sulfocationites

Based on studies of the ion-chromatographic retention of 16 aliphatic amines and hydrazines on Diasorb-130-Sulfo and Nucleosil 5 SA, the relevant ion-exchange constants were calculated. The selectivities of the retention of these compounds were compared. The mass-spectrometry detection was used after the chromatography separation. The characteristics of the mass spectra of the aliphatic amines and hydrazines were discussed. Optimum conditions of detection were determined.

Electrostacking with ion flow superposition as a method of concentration in electrophoresis

A method of online concentration in electrophoresis named “electrostacking with flow superposition” is offered that is an alternative to the standard “stacking”. The method is based on monitoring of the rate of ion motion in crossed channels of a cross-shaped interface due to the changes in the electric circuit parameters. Monitoring of the rate of ion motion allows carrying out the concentration by combining two principles: “electrostacking” and “superposition of ion flows”. The possibility of concentration is shown experimentally by the example of the anionic form of Methyl Orange in the electrostacking mode with superposition of ion flows. The suggested method allows obtaining tenfold values of the concentration factor with an experimental error sr = 4–15%.