Liquid chromatography ion trap/time-of-flight mass spectrometric study on the fragmentation of an acetildenafil analogue.

Liquid chromatography ion-trap time-of-flight mass spectrometry was employed to elucidate the fragmentation pathways of an analogue of acetildenafil. Based on the accurate masses of the parent ion, product ions and neutral losses of acetildenafil analogue, its fragmentation pathways were proposed. The information is useful for the on-line structural identification of unknown analogues of acetildenafil found as adulterants in herbal products.

Structural elucidation of propoxyphenyl isobutyl aildenafil, adulterant in a health supplement using high-resolution Orbitrap mass spectrometry.

A new sildenafil analogue, propoxyphenyl isobutyl aildenafil has been found in trace quantity from one health supplement. It has been purified by preparative high performance liquid chromatography (HPLC). The structural elucidation of this compound has been carried out using high-resolution Orbitrap mass spectrometry under two fragmentation modes, namely High energy Collision Dissolution (HCD) and Collision Induced Dissolution (CID). Under MS(3) experiments and CID mode, the isobutyl-bonded fragments of propoxyphenyl isobutyl aildenafil at m/z 313 and 297 have been compared with the reference ions derived from isobutyl sildenafil. The accurate mass measurement of each product ions has been carried out with the aid of Mass Frontier software (version 5.0). The mass error of all product ions is not more than 5.0ppm.

Detection of dehydroepiandrosterone and androsterone in a traditional Chinese herbal product.

Dehydroepiandrosterone (DHEA) and androsterone (ADT) were detected in a traditional Chinese herbal product by gas chromatography-mass spectrometry (GC-MS) and liquid chromatography tandem mass spectrometry (LC-MS/MS). DHEA and ADT were tentatively identified by comparing their electron ionization (EI) mass spectra with those in the GC-MS Wiley database. A multiple reaction monitoring (MRM) scan was performed in LC-MS/MS to confirm the presence of the DHEA and ADT in the herbal product extract. Both the [M + H]+ and the [M + NH4]+ of DHEA and ADT were selected as the precursor ions. DHEA was detected with ion transitions m/z 306.4 --> 271.2, 306.4 --> 253.3, 289.2 --> 270.9, 289.3 --> 253.1 while ADT was detected with ion transitions m/z 308.5 --> 273.6, 308.5 --> 255.3, 291.5 --> 273.5, 291.5 --> 255.2, which confirmed the presence of the two steroid hormones in the herbal product. Limits of detection (LODs) of 0.2 microg ml(-1) for DHEA and 0.3 microg ml(-1) for ADT were found in methanolic standard solutions when [M +NH4]+ of DHEA and ADT were selected as the precursor ions, which allowed the detection of DHEA and ADT at trace level without time-consuming derivatization.