Ethyl butanoate

Octan-2-ol (97%), 1-hexanol (99%), cis-3-hexenol (98%), trans-3-hexenol (97%), vanillin (99%), 2,6-dimethoxyphenol (99%), linalool (97%), terpinen-4-ol (≥95%), α-terpineol (90%), nerol (≥97%), geraniol (98%), linalool oxide (≥97%), β-citronellol (95%), p-cymene (99%), terpinolene (≥85%), γ-terpinene (≥97%), limonene (97%), 1,8-cineole (99%), 1,4-cineole(≥98.5%), β-damascenone (≥98%), isoamyl alcohol (98%), benzyl alcohol (≥99%), 2-phenylethanol (≥99%), ethyl acetate (99%), ethyl butanoate (99%), ethyl 3-methyl butanoate (≥98%), isoamyl acetate (≥95%), ethyl hexanoate (≥95%), phenylethyl acetate (99%), n-hexyl acetate (≥98%), ethyl lactate (≥98%), ethyl octanoate (≥98%), ethyl decanoate (≥98%), hexanoic acid (≥99%), octanoic acid (≥98%), α-phellandrene (95%), p-menthane-1,8-diol (97%), 3-methylbutanoic acid (99%), α-ionone (90%), 1-pentanol (99%), 1-butanol (≥99%), 2-butanol (≥99%), ethyl guaiacol (≥99%), vinyl guaiacol (≥98%), methyl-vanillate (99%), ethyl vanillate (99%), were supplied by Sigma Aldrich (Milan, Italy). Dichloromethane (≥99.8%) and methanol (≥99.8%), were provided by Honeywell (Seelze, Germany). Sodium chloride (≥99.5%) was supplied by Sigma Aldrich (Milan, Italy).

Reference standards (+) -β-Pinene (≥98.5%), 1-Octen-3-ol, borneol (≥95%), butyric acid (≥99.5%), citral (≥95%), cis-3-hexen-1-ol (≥98%), diacetyl, dimethyl sulphide, dimethyl trisulphide (≥98.5%), 3-methylbutanal (≥97%), 2-methylbutanal (≥95%), ethyl 2-methylbutanoate (99%), ethyl 2-methylpentanoate (internal standard, ≥99%), ethyl-3-methylbutanoate (≥98%), 3-methylbutyl-2-methylpropanoate (≥98%), 2-methylbutyl-2-methylpropanoate (≥95%), and ethyl cinnamate (99%), ethyl 2-methylpropanoate (≥99%), ethyl 3-methylbutanoate (≥98%), ethyl 4-methylpentanoate (≥97%), ethyl butanoate (≥99,5%), ethyl hexanoate (≥99.5%), eugenol (99.6%), furaneol (≥99%), geraniol (≥99%), hexanol (≥99%), 3-methylbutyl acetate (≥97%), linalool (97%), menthol (99%), methyl nonanoate (≥99.8%), myrcene (≥90%), geranyl acetate (≥97%), dimethyl disulphide (≥90%), limonene (97%), hexanal (≥98%), 3-hexenol (≥95%), 2-phenyl ethanol (≥99%), β-caryophyllene (≥80%), α-humulene (≥96%), humulene oxide, S-methyl 5-methylpentanthioate S-methyl hexanthioate, S-methyl 4-methylpentanoate and theaspirane (≥90%) were purchased from Sigma Aldrich (St. Louis, MO, USA).

All reagents utilized in this assay were of analytical quality. Sodium chloride (NaCl, 99.5%), and calcium chloride (CaCl₂, >99.0%) were obtained from Panreac (Spain, Barcelona). Ultrapure water was supplied from a Milli-Q^® system (Millipore); the 3-octanol used as internal standard and other VOCs for identification, namely, 1-butanol, 1-heptanol, 1-octanol, 1-propanol, (E)-2-hexenal, 2-methyl-butanal, 2-ethyl-1-hexanol, 2-methyl-1-propanol, 2-phenylethanol, acetaldehyde, benzaldehyde, ethanol, ethyl acetate, ethyl butanoate, ethyl decanoate, ethyl hexanoate, ethyl octanoate, ethyl propanoate, ethyl 3-hydroxybutanoate, hexyl acetate, and pentanal with purity up to 98% were acquired from Sigma Aldrich (Madrid, Spain). Helium gas purity of 5.0 (Air Liquide, Portugal) was utilized as the GC carrier gas. Solid-phase microextraction holder and divinylbenzene/carboxen/polydimethylsiloxane (DVB/CAR/PDMS) fiber were supplied from Supelco (Bellefonte, PA, USA). The Kovats index (KI) was calculated by the injection of a series of C₈ to C₂₀ straight-chain n-alkanes (at 40 mg L⁻¹ in n-hexane) produced by Fluka (Buchs, Switzerland).