Odp 2 olfactory detection port

GC-O analysis was performed on an Agilent 5975C-7890A GC-MS (Palo Alto, CA, USA) with a Gerstel ODP-2 olfactory detection port (Gerstel AG Enterprise, Mülheim an der Ruhr, Germany). Samples were separated and evaluated using an HP-INNOWax (60 m × 0.25 mm × 0.25 μm) column (Agilent, Palo Alto, CA, USA). The temperature at the injector port was 250 °C. A 1 μL sample was injected into the GC-O system in a splitless mode. The oven temperature was programmed as follows: An initial temperature of 40 °C was kept for 1 min and then increased to 230 °C at a speed of 5 °C/min, then held at this temperature for 3 min. Nitrogen was used as the carrier gas at a flow rate of 1.8 mL/min.
Aroma extract dilution analysis (AEDA) was used to determine the respective notes and intensities of volatiles. A series of 4-fold dilutions (i.e., 4⁰, 4¹, 4²) of the volatile extracts were prepared using the solvent n-hexane. The sniffing test was performed by three well-trained panelists in an alternating order at 2 h intervals with reference compounds. All panelists were trained for 60 h over a period of one month. Upon sniffing the effluents from the sniffing mask, the panelists recorded the retention time and aroma descriptors. The odor intensity of fragrance chemicals was evaluated with flavor dilution (FD) factors.

Aroma Extract Dilution Analysis (AEDA) is used in the analysis of key aroma components. The concentrated samples obtained by SAFE were gradient diluted, such as 1:2, 1:4, 1:8, …, 1:1024. The experiment was stopped at unodourable dilution concentration. This experiment can determine the FD factor of aromatic compounds.
The GC-O analysis was performed on the GC-MS system equipped with an ODP-2 olfactory detection port (Gerstel, Mühlheim an der Ruhr, Germany). The aroma-active compounds with the same chromatographic conditions as GC-MS. The effluent of GC was split 1:1 between the flame ionization detector and the sniffing port, the double amount of injection was used (2 μL).

GC-sniffing analysis was conducted for each group. One half of the column flow was directed to a heated sniffing port (ODP2 olfactory detection port, Gerstel GmbH & Co. KG, Mülheim an der Ruhr, Germany). To the sniffing port, humidified air (50–75% relative humidity) was carried at 1.02 ml min^-1 to prevent the nose from drying out. The three panelists, who are well versed in sea urchin gonad quality and share common perceptions, recorded the retention time and the related description of the aroma compounds by writing in a paper. They could record without taking off their nose from the sniffing port.