Tricosane

Pyridine, tricosane, N,O-bis(trimethylsilyl)trifluoroacetamide were obtained from Sigma-Aldrich (St. Louis, MO, USA), catalyst Kjeltabs was obtained from Foss (Höganäs, Sweden), and all other chemicals were of analytical grade.

The following chemicals were used as received: perfluoropentane (C₅F₁₂, 98%, Strem Chemicals, Newburyport, MA, USA); perfluorohexane (C₆F₁₄, 99%, FluoroMed, Round Rock, TX, USA); perfluorododecane (>99%, Fluoryx Labs, Carson City, NV, USA); Krytox 157 FSH oil (Miller-Stephenson Chemicals, Danbury, CT, USA); 1,2-dibehenoyl-sn-glycero-3-phosphocholine (DBPC) (99%, Avanti Polar Lipids, Alabaster, AL, USA); N-(methylpolyoxyethylene oxycarbonyl)-1,2-distearoyl-sn-glycero-3-phosphoethanolamine (DSPE-PEG5K) (NOF America, White Plains, NY, USA); octadecane (99%), heneicosane (98%), tricosane (99%), tetracosane (99%), and chloroform (≥99.9%) (Sigma-Aldrich, St. Louis, MO, USA); nonadecane (99%, Acros Organics, NJ, USA); eicosane (99%, Alfa Aesar, Ward Hill, MA, USA); docosane (98%, TCI, Portland, OR, USA); DiO fluorescent probe (excitation, 484 nm; emission, 501 nm) (Invitrogen, Eugene, OR, USA); and ultrapure deionized (DI) water from Millipore Direct-Q (Millipore Sigma, St. Louis, MO, USA).

A GC-MS 7890B gas chromatograph equipped with a 5977B MSD mass spectrometer (Agilent Technologies, Santa Clara, CA, USA), with an Agilent HP-5MS column (30 m, 0.25 µm, 0.25 μm film thickness) was used in the experiments. The carrier gas used was helium at 99.999% (BOC, Sydney, Australia). The conditions for the GC-MS were as follows: injector port temperature of 270 °C; initial oven temperature of 60 °C, which increased to 320 °C (at 5 °C/min); MS Quad at 150 °C; MS source at 230 °C; pressure at 10.629 psi. The flow rate was 1.2 mL/min; the splitless was 30 mL/min at 1.0 min. The total run time was 45.40 min.
Standard n-alkane (C₇-C₃₀) reference material containing 1000 μg/mL of each component (decane, docosane, dodecane, eicosane, heneicosane, heptacosane, heptadecane, hexacosane, hexadecane, heptane, nonacosane, nonadecane, nonane, octacosane, octadecane, octane, pentacosane, pentadecane, tetracosane, tetradecane, triacontane, tricosane, tridecane and undecane) in hexane was purchased from Sigma-Aldrich (catalogue number 49451-U; Castle Hill, NSW, Australia), as was n-hexane (95%, catalogue number 270504-2L).

Chemical standards of tricosane (99%) and pentacosane (99%) were purchased from Sigma-Aldrich Inc. (St. Louis, MO, USA) and BeanTown Chemical (Hudson, NH, USA), respectively. Hexacosane (99%) and heptacosane (99%) were obtained from Alfa Aesar (Ward Hill, MA, USA). (6Z,9Z)-heptadeca-6,9-diene was synthesized as described above.

Heptane (99%), nonane (99%), undecane (≥99%), dodecane (99%), tridecane (≥99%), tetradecane (≥99%), pentadecane (≥99%), hexadecane, heptadecane (99%), octadecane (99%), nonadecane (99%), eicosane (99%), heneicosane (≥99.5%), docosane (99%), tricosane (99%), tetracosane (99%), pentacosane (99%), hexacosane (99%), octacosane (99%), and triacontane (99%) were purchased from Sigma-Aldrich (Darmstadt, Germany). Octane (98%) and decane (≥99%) were purchased from Sigma-Aldrich (St. Louis, MO, USA). Acetone and hexane were of HPLC grade and purchased from Elite Advanced Materials Sdn. Bhd. (Selangor, Malaysia). Ultrapure water (18.2 MΩ cm⁻¹) was purified by a Millipore Milli-Q system (Bedford, MA, USA).

Organic solvents used were as follows: acetonitrile, heptane, and 2-propanol Optima™ LC/MS grade were supplied by Fisher Chemical. Ultrapure water was produced using the Milli-Q Plus 185 system (Millipore, Billerica, MA, United States). O-methoxyamine hydrochloride, sialylation-grade pyridine, BSTFA (N,O-bis(trimethylsilyl)trifluoroacetamide) with 1% TMCS (trimethylchlorosilane), C8–C40 alkane calibration standard mix, C:18 methyl ester, and tricosane analytical standard were purchased from Sigma-Aldrich (St. Louis, MO, United States).