MS-FINDER and SIRIUS for phenolic compound identification from high-resolution mass spectrometry data.

LC-HR-MS/MS is the predominant analytical technique in phenolic compound (PC) research. However, the manual interpretation of mass spectra is a heavy nontrivial time-consuming task and depends on mass spectrometry and phenolic compounds fragmentation deep knowledge. We think this manual approach should be partially translated into a practical software that allows users to perform such complicated analyses. In silico fragmentation software have been tested for small molecule identification, MS-FINDER and SIRIUS stood out at identification contests and challenges. We evaluated both software to identify PC from two data categories: 1st MS/MS spectra from 18 phenolic compound standards (PCS) and 2nd phenolic compounds from 8 food samples (FPC) (coffee, green tea, cranberry juice, grape juice, orange juice, apple juice, soy extract and parsley extract). MS-FINDER and SIRIUS were able to correctly identifymore than 90% of the PCS by LC-HR-MS/MS. The main FPC were also correctly identified by MS-FINDER (70%) and SIRIUS (38%). We highlight that these software were unable to differentiate PC isomers. This task is only possible by using additional information, such as chromatographic behavior and manual analysis of the relative intensity of fragments in the MS/MS spectra. Therefore, the combination of initial screening by using MS-FINDER and SIRIUS with manual analyses of additional information is a powerful and efficient approach for identifying phenolic compounds.

Comprehensive identification and quantification of unexploited phenolic compounds from red and yellow araçá (Psidium cattleianum Sabine) by LC-DAD-ESI-MS/MS.

LC-DAD-ESI-MS/MS was used to comprehensively characterise the non-extractable phenolic compounds (NEPC) in red and yellow araçá genotypes. Results showed a total of 45 and 43 phenolic compounds in the NEPC fraction and, similarly, 51 and 50 compounds in extractable phenolic compounds (EPC) fraction from red and yellow araçá, respectively. Gallic acid and ellagic acid were the unique compounds found in both fractions. The NEPC fraction represented about 35% (m/m) of the total phenolic content and was characterised by an abundance of phenolic acids, while the EPC fraction was rich in flavanols. Although NEPC represented one-third of the total phenolic compounds found in araçá, its antioxidant capacity (against peroxyl radical) was 50% higher than the EPC fraction. The results of this work show that the NEPC fraction of araçá has great diversity and a relatively high concentration of low-molecular-weight phenolic compounds with high antioxidant capacity.