Agilent msd5975c ms detector

The chemical analysis of EOs were carried out by gas chromatography and mass spectrometry (GC–MS) using an Agilent 7890A GC (HPST, s.r.o., Praha, Czech Republic) coupled to an Agilent MSD5975C MS detector (Agilent Technologies, Palo Alto, CA, USA) with a HP-5MS column (30 m × 0.25 mm, 0.25 μm-film-thickness) (HPST, s.r.o., Praha, Czech Republic). Relative proportions of essential oils components were assessed by gas chromatography using a gas chromatograph with flame ionization detector (GC–FID) using Agilent 7890A (Agilent Technologies, Palo Alto, CA, USA) with HP-5MS, 30 m × 0.25 mm, 0.25 μm-film-thickness. Both analyses were prepared in the same way according to Božik et al. [21 (link)] and Klouček et al. [22 (link)]. The authentic standards (Sigma–Aldrich, Munich, Germany) were used for components identification. The identification was based on a comparison of the obtained mass spectra of the different components. The chemical components were quantified by dividing peak area by the total area of all peaks and major compounds (only peaks over 0.1% were counted).

Various conventional preservatives that are commonly used in the food industry, including sodium chloride (Lach-Ner, Neratovice, CZ), sodium benzoate (Sigma-Aldrich, St. Louis, MO, USA), sorbic acid (Sigma-Aldrich, St. Louis, MO, USA), sucrose (Lach-Ner, Neratovice, CZ), and citric acid (Lach-Ner, Neratovice, CZ), were employed in this experiment. In addition, essential oils (EOs) of thyme (Thymus vulgaris, Sigma-Aldrich, St. Louis, MO, USA), oregano (Origanum vulgare, Biomedica, Prague, CZ), and lemongrass (Cymbopogon citratus, Biomedica, Prague, CZ) and freshly squeezed lime juice were also used as additives due to their well-established antibacterial activity. The compositions of EOs were previously analysed using GC/MS and reported [23 (link),24 (link)]. The GC-MS analyses were performed using an Agilent 7890A GC coupled with an Agilent MSD5975C MS detector (Agilent Technologies, Palo Alto, CA, USA). Thymol (44%) and p-cymene (18%) were found to be the major components of thyme oil, while carvacrol (70%) was the main constituent of oregano essential oil. The major components of lemongrass oil were geranial (40%) and neral (32%).

The constituents were identified and the relative composition of the salvia hydrolates was determined by gas chromatography followed by mass spectrometry (GC/MS), as described by [52 (link)]. Prior to injection, hydrolates were extracted in hexane in a ratio of 1.5:1 and dried over anhydrous sodium sulphate according to [37 (link)]. Analyses were carried out using an Agilent 7890A GC coupled to an Agilent MSD5975C MS detector (Agilent Technologies, Palo Alto, CA, USA) with a HP-5MS column (30 m × 0.25 mm, 0.25 mm film thickness). The analytical conditions were as follows: injector temperature 250 °C and the oven temperature from 60 °C to 231 °C at 3 °C/min. Components were identified by matching their mass spectra and retention indices with those of authentic samples and/or NIST/Wiley spectra libraries and available literature data [53 ]. Relative proportions were calculated by dividing the individual peak area by the total area of all peaks. Only compounds with more than 1% were considered.