5 ethyl 3 hydroxy 4 methyl 2 5h furanone

Sodium chloride, magnesium chloride, potassium chloride, calcium chloride, 2-amino-2-(hydroxymethyl)-1,3-propanediol (Trizma base), hydrochloric acid, 2,5-dimethyl-4-hydroxy-3(2H)-furanone (furaneol), 5-Ethyl-3-hydroxy-4-methyl-2(5H)-furanone (maple furanone), 4,5-Dimethyl-3-hydroxy-2,5-dihydrofuran-2-one (sotolon), 5-Ethyl-4-hydroxy-2-methyl-3(2H)-furanone (homofuraneol), 2-Methoxyphenol (guaiacol), and ethylenediaminetetraacetic acid disodium salt dihydrate (EDTA) were purchased from Sigma-Aldrich (Munich, Germany). Taq DNA polymerase, dNTPs solution, TAE and TBE electrophoresis buffers, DNA extraction kits, DNA cloning kit, Exonuclease I, and the Escherichia coli DH5α strain were purchased from Thermo Fisher Scientific (Waltham, MA, USA). SYBR Gold dye was purchased from Invitrogen (Thermo Fisher Scientific). SYBR Green I dye was obtained from Lumiprobe Ltd., (Moscow Russia). Streptavidin-coated magnetic beads were supplied by New England Biolabs (Ipswich, MA, USA).
The single-stranded DNA library B1_bank was synthesized by DNA Synthesis Ltd., Moscow, Russia. All primers for DNA amplification were ordered from the DNA Synthesis Ltd., Moscow, Russia. The B1_cap was either purchased from DNA Synthesis Ltd., Moscow, Russia or from Microsynth AG (Balgach, Switzerland). Candidate aptamer sequences were synthesized by Evrogen Ltd. (Moscow, Russia).

Reference compounds of the odorants identified
were obtained from the commercial sources given in parentheses: acetic
acid (Merck, Darmstadt, Germany); butane-2,3-dione, butanoic acid,
γ-decalactone, δ-decalactone, γ-dodecalactone, δ-dodecalactone,
ethyl butanoate, ethyl hexanoate, 5-ethyl-3-hydroxy-4-methyl-2(5H)-furanone, hexanoic acid, 3-hydroxy-4,5-dimethyl-2(5H)-furanone, 4-hydroxy-3-methoxybenzaldehyde (vanillin),
2-isopropyl-3-methoxypyrazine, 3-methylbutanal, 2-methylbutanoic acid,
3-methylbutanoic acid, 3-methylbutanol, 2-methylpropanoic acid, γ-nonalactone,
(E)-2-nonenal, pentanoic acid, 2-phenylacetic acid
and 2-phenylethanol (Sigma-Aldrich Chemie, Taufkirchen, Germany);
and 4-ethyloctanoic acid (ABCR GmbH & Co. KG, Karlsruhe, Germany).
The following reference compounds were synthesized as previously
described: (Z)-2-nonenal^{27 (link)} and trans-4,5-epoxy-(E)-2-decenal.^{28 (link)}