Analysis of impurities in vertilmicin sulfate by liquid chromatography ion-trap mass spectrometry.

The characterization of impurities present in vertilmicin by liquid chromatography (LC) coupled with mass spectrometry (MS) is described. A reversed phase (RP)-LC method using a C18 column resistant to basic pH with an alkaline (pH 11) aqueous mobile phase was developed and coupled to MS with an electrospray ionization (ESI) source in the positive ion mode which provides MS(n) capability. In total, 18 impurities were detected in a commercial sample.

Impurity profiling of micronomicin sulfate injection by liquid chromatography-ion trap mass spectrometry.

The characterization of impurities present in micronomicin sulfate injection by liquid chromatography (LC) coupled with mass spectrometry (MS) is described. A reversed phase (RP)-LC method using a C₁₈ column resistant to an alkaline (pH 11) aqueous mobile phase was developed and coupled to MS with an electrospray ionization (ESI) source in the positive ion mode which provides MS(n) capability. A total of thirty six impurities were detected in commercial samples: five impurities were identified by comparison of their fragmentation patterns with those of available related substances, eleven of them were identified in accordance with relevant literature, while the other twenty impurities were newly identified using the MS/MS spectra of the available related reference substances as interpretative templates combined with knowledge of the nature of functional group fragmentation behaviors.

Impurity profiling of etimicin sulfate by liquid chromatography ion-trap mass spectrometry.

A reversed phase (RP)-LC method using a C(18) column resistant to basic pH and an alkaline (pH 10) aqueous mobile phase was developed and coupled to MS with an electrospray ionization (ESI) source in the positive ion mode which provides MS(n) capability. In total, 26 impurities were detected in a commercial sample. The structures of the impurities were proposed based on comparison of their fragmentation patterns with those of the available reference substances, the synthetic route and literature data.

[Related substances in purified alliin determined by HPLC-MS/MS].

To study the related substances in purified alliin, HPLC-MS/MS method carried out on a Phenomenex NH2 column was used for screen and identification of the related substances with full scan MS spectra determination of their [M + H] + ions and then the analyses of the retention time, product MS spectra and/or chemical reference standards. The full scan HPLC-MS chromatogram showed that there were seven major related substances in the purified alliin and their m/z of the [M + H] + ions with increasing retention were 116, 133, 147, 152, 175, 178 and 178, separately. And they were identified as proline, asparagine, glutamine, methiin, arginine, isoalliin and cycloalliin (both were isomers of alliin), respectively.

[Study on water of crystallization in tazobactam].

Aim: To investigate whether tazobctam has crystallization water.

Methods: In order to establish a method for water content determination in tazobctam, many methods including Karl Fischer titration, weight loss on drying, TGA, DSC and X-ray diffraction experiment of an orthorhombic form were studied.

Results: The water content of the same batch tazobactam determined by different mthods was different.