Targeted Analysis of Veterinary Drugs in Food Samples by Developing a High-Resolution Tandem Mass Spectral Library.

Veterinary drug residues present in foods can pose severe health threats to the population. The present study aims to develop a high-resolution mass spectral library of 158 veterinary drugs of 16 different classes for their rapid identification in food samples through liquid chromatography-high-resolution electrospray ionization-tandem mass spectrometry (LC-HR-ESI-MS/MS). Standard drugs were pooled according to their log P values and exact masses before analysis. Spectra were collected at system automated collision energy, i.e., of 25-60 eV and four predetermined collision energies (10, 20, 30, and 40 eV) for each compound using a schedule precursor list of [M + H]+, [M + Na]+, and [M + NH4]+ ions. The utility of the developed database was checked by analyzing food samples. A total of 17 veterinary drugs based on the reference standard retention times (RTs), HR-MS spectra, and MS/MS spectra were identified in the analyzed samples. Moreover, five veterinary drugs were selected for quantitative analysis, including doxycycline hyclate, lincomycin, sulfasalazine, moxifloxacin, and diphenoxylate, using liquid chromatography-ion trap mass-spectrometry (LC-IT-MS). Concentrations of the drug were obtained to vary from 0.0805 to 0.9731 mg/kg in food samples and were found to be exceeded in most of the cases as per the maximum residue levels described by Food and Agriculture Organization (FAO)/World Health Organization (WHO). The MS data were submitted to the MetaboLights online database (MTBLS2914). This study will help in the high-throughput screening of multiclass veterinary drugs in foodstuffs.

High-Throughput Detection of an Alkaloidal Plant Metabolome in Plant Extracts Using LC-ESI-QTOF-MS.

Plant alkaloids represent a diverse group of nitrogen-containing natural products. These compounds are considered valuable in drug discovery and development. High-throughput identification of such plant secondary metabolites in complex plant extracts is essential for drug discovery, lead optimization, and understanding the biological pathway. The present study aims to rapidly identify different classes of alkaloids in plant extracts through the liquid chromatography with electrospray ionization-tandem mass spectrometry (LC-ESI-MS/MS) approach using 161 isolated and purified alkaloids. These are biologically important unique alkaloids belonging to different sub-classes such as isoquinoline, quinoline, indole, tropane, pyridine, piperidine, quinolizidine, aporphine, steroidal, and terpenoid. The majority of these are not available commercially and are known to manifest valuable biological activities. Four pools of a maximum of 50 phytostandards each were prepared, based on their log P value to minimize co-elution for rapid and cost-effective analyses. MS/MS spectra were acquired in the positive ionization mode by using their [M + H]+ and/or [M + Na]+ with both the average collisional energy (25.5-62 eV) and individual collisional energies (10, 20, 30, and 40 eV). Accurate mass, high-resolution mass spectrometry (HR-MS) data, MS/MS data, and retention times were curated for each compound. The developed LC-MS/MS method was successfully used to interrogate and fast dereplicate alkaloids in 13 medicinal plant extracts and a herbal formulation. A total of 56 alkaloids were identified based on the reference standard retention times (RTs), HR-MS spectra, and/or MS/MS spectra. The MS data have been submitted to the MetaboLights online database (MTBLS2914). The mass spectrometric and chromatographic data will be useful for the discovery of new congeners and the study of biological pathways of alkaloids in the plant kingdom.

Quantification of steroidal alkaloids in Buxus papillosa using electrospray ionization liquid chromatography-triple quadrupole mass spectrometry.

Buxus papillosa is one of the most extensively studied species of the genus Buxus known to possess steroidal alkaloids which can be used for assessing the various pharmacological activities of this plant. This paper describes the liquid chromatography-electrospray ionization triple quadrupole mass spectrometry (LC-ESI-QQQ-MS) method for the quantification of six steroidal alkaloids as chemical markers in the extracts of leaves, roots and stems of B. papillosa. Quantitative MS/MS analysis was carried out by optimization of the most sensitive transition for each analyte. This has yielded detection and quantification limits of 0.486-8.08 ng/mL and 1.473-24.268 ng/mL, respectively for all analytes. Linearity of response was also achieved and the regression coefficient found to be >0.99 for all analyzed compounds. The newly developed MRM (Multiple Reaction Monitoring) method showed excellent sensitivity for the quantification of steroidal alkaloids within 15 min run time. This paper describes the application of LC-QQQ-MS technique for steroidal alkaloids analysis in plant samples.