Identification of isocephalomannine in the presence of cephalomannine isomers and alkali metal ion adducts in a paclitaxel active pharmaceutical ingredient using electrospray tandem mass spectrometry.

A strategy is developed for the identification of isocephalomannine in the presence of alkali metal ion adducts and other cephalomannine isomers in a paclitaxel active pharmaceutical ingredient. Intact molecular ion analyses and a sub-structural study have been performed for the differentiation of isocephalomannine (2-debenzoylpaclitaxel-2-pentenoate) from cephalomannine and 7-epi-cephalomannine. A comparative study of the cephalomannine isomers was carried out using molecular ions (MS) and fragmentation patterns (MS/MS) for sub-structural analysis. An attempt has been made to identify isocephalomannine in Cremophor(R) EL formulations.

Identification of degradation products from aqueous carboplatin injection samples by electrospray mass spectrometry.

Four different carboplatin injection samples in water ( approximately 10mg/ml) stored at room temperature were investigated for degradation products by electrospray liquid chromatography-mass spectrometry (ESI/LC-MS). A mass spectrometer compatible mobile phase system with 0.02% formic acid and methanol was used to resolve the impurities. Possible chemical structures of the unknown impurities and its degradation mechanism were proposed based on its experimental results and literature findings.

A simple method of isolation of chloramphenicol in honey and its estimation by liquid chromatography coupled to electrospray ionization tandem mass spectrometry.

To detect sub-ppb levels of the antibiotic chloramphenicol in honey matrix, a convenient method of extraction and measurement using liquid chromatography with detection by tandem mass spectrometry (LC/MS/MS) was developed. Honey samples fortified with chloramphenicol and isotopically labeled chloramphenicol were extracted using diatomaceous-based supported liquid-liquid extraction cartridges to generate a standard calibration curve. Four MS/MS transitions were used for quantification and four other transitions for confirmation of chloramphenicol. The limit of detection for chloramphenicol was 0.05 ng/g and the lower limit of quantification was 0.1 ng/g. Several commercial honey samples were analyzed for chloramphenicol content using this method.