Agilent 5973 c mass spectrometer

The determination of volatile compounds was carried out according to Vasta’s method [15 (link)] with appropriate modifications. GC-MS analysis was operated using an Agilent 7890 A gas chromatograph (Agilent Technologies, Santa Clara, CA, USA) coupled to an Agilent 5973 C mass spectrometer. The following conditions were used: For the SPME analysis, desorption was at 280 °C for 4 min in splitless mode and MS was detected with no solvent delay; the ion source and quadrupole were set at 230 °C and 150 °C, respectively. The mass spectra were obtained in electron ionization mode (70 eV), and the range of mass spectrum scanning was 30–550 m/z.

Both free-volatile and bound-form aroma compounds were extracted by headspace solid-phase microextraction (HS-SPME). Agilent 6890 GC coupled with Agilent 5973C mass spectrometer (MS) was used for the aroma determination. GC was equipped with an HP-INNOWAX capillary column (60 m × 0.25 mm, 0.25 μm, J&W Scientific, Folsom, CA, United States) to separate volatile compounds. The carrier gas was high purity helium with a flow rate of 1 ml/min. The oven program was set as follows: 50°C for 1 min, increased to 220°C at a rate of 3°C/min, and held at 220°C for 5 min. Identification and quantification of volatile compounds followed our research group method (Wang et al., 2019 (link)). Concentrations of volatile compounds were expressed as μg/L grape juice.