Ethyl octadecanoate (trans-11)/ethyl isooleate - analytical standard,≥99%

Cat. No.: E1509237

GRADE & PURITY Analytical standard, ≥99%

Storage

Room temperature

Shipped In

Normal

Specifications

Specifications & Purity

analytical standard,≥99%

Storage

Room temperature

Shipped In

Normal

Grade

Analytical standard

Purity

≥99%

Application Protocols

No item-specific, vendor-validated protocols are provided. The following general workflow notes are offered for researchers developing analytical methods with fatty acid ethyl ester standards (literature-based; adapt as needed):

• Stock solution preparation:

  • Dissolve the standard gravimetrically in n-hexane or isooctane (e.g., 1–10 mg/mL). Mix gently; avoid ultrasonication that may introduce heat/air.
  • Aliquot into amber autosampler vials with PTFE-lined caps; minimize headspace; consider nitrogen overlay.

• Calibration:

  • Prepare serial dilutions to span the expected sample concentration range (e.g., 0.1–100 µg/mL for GC-FID).
  • Verify linearity and response factors; assess isomer resolution and peak identity via retention times on a polar column.

• Injection and analysis:

  • Use deactivated glass liners; inlet 250–300 °C; split ratios adjusted to keep on-column mass within detector linear range.
  • Employ slow oven ramps on long, highly polar columns to resolve positional and cis/trans isomers.

• Quality controls:

  • Include a mid-level check standard every 10–20 injections to track drift.
  • Monitor for oxidation (new minor peaks) in unsaturated ester solutions; remake solutions as needed.

For regulated work, follow internal SOPs and document system suitability criteria (Rs, tailing factor, %RSD of response).

Biological Roles

This product is intended for research use as an analytical standard. The following provides general biochemical context for long-chain fatty acid ethyl esters (FAEEs); these are not item-specific claims.

• Formation and occurrence (literature):

  • FAEEs can form enzymatically or non-enzymatically via esterification of long-chain fatty acids with ethanol. In biological systems, FAEEs have been detected as minor lipid constituents and as metabolites associated with ethanol exposure.

• Transport and metabolism (general):

  • Compared with triglycerides and free fatty acids, FAEEs are less common energy stores. They can undergo hydrolysis by esterases to liberate free fatty acids, which then enter β-oxidation or lipid remodeling pathways.
  • Unsaturated C18:1 derivatives retain a cis/trans double bond that can influence membrane interactions and enzyme recognition.

• Analytical biomarkers (research context):

  • FAEEs, including C18 species, are used as markers in research for alcohol intake, meconium testing, and lipidomics profiling, though specific clinical applications are beyond the scope of this catalog item.

• Relevance to this standard:

  • Availability of defined C18 FAEE isomers (positional and geometric) supports accurate lipidomics method validation, isomer resolution studies, and retention index calibration on polar columns.

Note: No medical or clinical use is implied. For research use only.

Buffer Applications

Not typically applicable. Long-chain fatty acid ethyl esters are highly hydrophobic and essentially insoluble in aqueous buffers, and they do not function as buffering agents.

• Practical guidance:
  • For any aqueous/biological sample preparation, first extract into an appropriate organic phase (e.g., hexane, isooctane, MTBE) before chromatographic analysis.
  • If emulsions form during biphasic workups, add brine or adjust solvent polarity to achieve phase separation.

For solution preparation details, see Solvent Selection and Application Protocols (general) in related sections.

Green Alternatives

Greenness considerations for this analytical standard pertain mostly to solvent choice and sample handling, since the analyte itself is required for method performance.

• Solvent selection (greener choices; literature-based):

  • Prefer isooctane or heptane over n-hexane where feasible to reduce n-hexane exposure concerns.
  • Ethanol or ethyl acetate can dissolve small amounts of FAEE standards for certain workflows, but verify compatibility with GC methods (solvent peak shape, inlet discrimination) and analyte stability.

• Sample size and waste minimization:

  • Use microvolume syringes and low-dead-volume vials to reduce solvent and standard consumption.
  • Employ on-column or PTV injection to improve transfer efficiency and reduce repeats.

• Comparative overview (general):

  • Hexane: excellent volatility/compatibility but occupational exposure concerns; substantial VOC.
  • Isooctane/heptane: similar chromatographic performance; lower neurotoxicity profile than hexane.
  • Ethyl acetate: biodegradable, acceptable for LC; less ideal for GC of high boilers due to polarity and potential hydrolysis over long storage.

• Packaging/handling:

  • Consolidate calibration levels by serial dilution to limit primary standard handling.
  • Store working solutions in amber glass with PTFE-lined caps to extend life, minimizing repeat preparations and waste.

Note: Any substitution must preserve calibration integrity and chromatographic performance; verify with system suitability tests.

Pharmaceutical Uses

No therapeutic claims are made for this product. As an analytical standard, it is intended for research and quality control.

• General industry context for related materials (literature; not item-specific):

  • Certain long-chain fatty acid ethyl esters (e.g., ethyl oleate) have been used as nonaqueous vehicles, solvents, or excipient components in formulation development, offering good solvency for lipophilic actives and low volatility.
  • In process analytics, FAEE standards are used to validate methods for residual solvents, impurities, or composition of lipid-based excipients and biodiesel (EN/ASTM) matrices.

• Laboratory/QA applications:

  • System suitability and calibration of GC-FID/GC-MS methods used to characterize excipient lipid profiles or to assess transesterification products.
  • Stability-indicating methods: tracking isomerization, oxidation, or hydrolysis under stress conditions.

Any use in pharmaceutical manufacturing must be supported by internal validation and regulatory documentation. Refer to the CoA/SDS for quality attributes relevant to your intended analytical application.

Physical Properties

• Item-specific data: Not specified for this item; refer to CoA/Spec Sheet.

• Literature values (for closely related pure components; not specifications for this item):

  • Ethyl stearate (C18:0 ethyl ester):
    • Appearance: white to colorless solid/waxy liquid near ambient (mp ~32–35 °C, literature)
    • BP: ~216–220 °C at ~10 mmHg (literature); decomposes/nebulizes under atmospheric distillation
    • Density: ~0.86–0.87 g/mL at 25 °C (literature)
    • Refractive index: nD20 ~1.443–1.447 (literature)
    • Solubility: insoluble in water; soluble in nonpolar/medium-polar organics (hexane, toluene, EtOAc) (literature)
  • C18:1 ethyl esters (e.g., ethyl oleate, ethyl trans-11-octadecenoate):
    • Appearance: colorless to pale-yellow liquid at room temperature (literature)
    • BP: ~215–220 °C at ~10 mmHg (literature)
    • Density: ~0.87–0.88 g/mL at 25 °C (literature)
    • Refractive index: nD20 ~1.450–1.455 (literature)
    • LogP: typically >6 (very hydrophobic; literature)
    • Water solubility: negligible; high solubility in apolar solvents (literature)

• Practical notes (general):

  • Mixtures of saturated/unsaturated C18 ethyl esters tend to be liquid or soft at ambient temperature, with viscosity increasing as the saturated fraction rises (literature).
  • For GC analytics, injection at elevated inlet temperatures (e.g., 250–300 °C) is typical; esters are stable under standard GC conditions (literature).

Quality and Grades

• Item-specific quality: Analytical standard.

  • Intended for calibration, system suitability, and qualitative/quantitative analysis in chromatography (e.g., GC-FID/GC-MS) and related analytical platforms.
  • Emphasis is on identity, stability, and traceable preparation; consult CoA for purity, composition, and uncertainty where applicable.

• What “Analytical standard” typically implies (general; verify on CoA):

  • High chemical integrity with controlled isomeric composition where relevant.
  • Documented traceability (e.g., weighing records, batch records); may include certified concentration if supplied in solution (not specified for this item).
  • Low-level contaminants that could interfere with target analyte peaks are minimized; however, exact impurity profiles and limits are CoA-specific.

• Stabilizers/antioxidants: Not specified for this item; refer to CoA/Spec Sheet. Unsaturated esters are sometimes packaged under inert gas or with minimal headspace to reduce oxidation (general note).

• Fit for purpose:

  • Suitable for establishing retention times, resolution of positional/geometry isomers on highly polar GC phases (e.g., cyanopropyl silicone), and validating quantitation of C18 ethyl esters in oils, biodiesel (FAEE matrices), and biological lipid extracts.

• Documentation: For regulated workflows, retain the CoA, SDS, and any calibration certificates with your analytical records.

Reaction and Applications

As an analytical standard, this material is primarily used to establish retention indices and resolve C18 ethyl ester isomers in lipid and biodiesel analytics. Beyond analytics, C18 ethyl esters exhibit characteristic reactivity of long-chain esters and internal alkenes (for the unsaturated isomer).

• Analytical applications (primary use):

  • GC-FID/GC-MS method development and calibration for fatty acid ethyl esters (FAEEs).
  • Assessment of column selectivity/resolution for positional (Δ9 vs Δ11) and geometric (cis/trans) C18:1 isomers on polar phases (e.g., SP-2560, CP-Sil 88).
  • System suitability: peak shape, resolution (Rs) between isomers, reproducibility of k′ and selectivity α.

• Representative chemical transformations (general chemistry of components; literature):

  • Hydrolysis/transesterification to the corresponding free acids (stearic or octadecenoic acids) or other esters (e.g., methyl esters for FAME profiling).
  • Catalytic hydrogenation of C18:1 ethyl esters to saturated ethyl stearate.
  • Epoxidation of the C=C (for unsaturated isomer) using peracids, followed by ring-opening to diols.
  • Cross-metathesis/isomerization of internal alkenes under Ru catalysts (on unsaturated isomer).

• Practical notes:

  • For rigorous quantitation, prepare gravimetric standards and validate stability (autosampler dwell, room temperature bench time).
  • Avoid strong acids/bases during storage to prevent transesterification that could alter calibration.
  • Track injector liner activity; polar silanols can cause discrimination of high-boiling esters—deactivated liners are recommended.

Reaction Conditions

General literature conditions for transformations of C18 ethyl esters and C18:1 ethyl esters (for research planning; not specifications for this item):

• Hydrolysis/transesterification:

  • Base-catalyzed (NaOMe/MeOH, 0.1–1.0 mol%, 20–50 °C, minutes–hours) → rapid FAME formation for GC.
  • Acid-catalyzed (H2SO4/ROH, 0.5–5 wt%, reflux) → broader substrate tolerance; slower; monitor to avoid side reactions.

• Reduction:

  • LiAlH4 (THF, 0 °C to rt, 1–3 h) → primary alcohol (C18) in high yield; quench carefully.
  • DIBAL-H (–78 °C to –20 °C) → aldehyde intermediate; control stoichiometry and temperature.

• Hydrogenation (unsaturated isomer):

  • H2, Pd/C (5–10%), 1–5 bar, rt–50 °C, 1–4 h → saturated ethyl stearate.

• Epoxidation/dihydroxylation (unsaturated isomer):

  • m-CPBA (DCM, 0 °C to rt) → epoxide; subsequent acid-catalyzed ring opening yields diols/halohydrins.
  • OsO4/NMO (t-BuOH/H2O) → vicinal diol; handle OsO4 with extreme caution.

• GC analytical conditions (typical, literature):

  • Columns: highly polar cyanopropyl silicone (e.g., 100 m × 0.25 mm, 0.2 µm).
  • Oven: 140–240 °C ramps (1–3 °C/min) to resolve C18:1 positional/cis-trans isomers.
  • Inlet: 250–300 °C, split or splitless; detector: FID at 300–350 °C.

Always verify conditions on small scale and tailor to your apparatus, substrate purity, and safety constraints.

Safety and Handling

• Item-specific hazard data (from Product Data):

  • Signal Word: Not specified for this item; refer to SDS.
  • H-Statements: Not specified for this item; refer to SDS.
  • GHS Classification/Pictograms: Not specified for this item; refer to SDS.

• General safety guidance for long-chain fatty acid ethyl esters (literature/industry practice; not item specifications):

  • Typically classified as combustible liquids with low acute toxicity; may cause mild skin/eye irritation. Avoid inhalation of mists/vapors generated at elevated temperatures.
  • PPE: lab coat, safety glasses, and appropriate chemical-resistant gloves (e.g., nitrile). Use in a fume hood when preparing volatile samples for GC or when heating.
  • Incompatibilities: strong oxidizers (risk of exotherm), strong acids/bases may catalyze hydrolysis/transesterification. Avoid prolonged exposure to air/heat/light to limit autoxidation of unsaturated esters.
  • First aid (overview):
    • Skin: wash with soap and water.
    • Eyes: rinse cautiously with water for several minutes; remove contact lenses if present.
    • Inhalation: move to fresh air; seek medical attention if symptoms persist.
    • Ingestion: rinse mouth; do not induce vomiting; seek medical advice.
  • Fire-fighting: use dry chemical, CO2, or foam; cool containers with water spray. Combustion may produce CO/CO2.

Always consult the product’s SDS for authoritative hazard classification, exposure limits, and response measures. For research use only.

Solvent Selection

This product comprises hydrophobic long-chain ethyl esters and is typically handled in nonpolar or medium-polar organic solvents for preparation of analytical solutions.

• Polarity and miscibility (general properties for C18 ethyl esters):

  • Highly nonpolar; essentially insoluble in water.
  • Freely soluble in n-hexane, isooctane, heptane, toluene, chloroform, DCM; moderately soluble in ethyl acetate; limited solubility in acetonitrile and alcohols at room temperature.

• Recommended solvents by application (general guidance):

  • GC-FID/GC-MS standards: n-hexane or isooctane are common due to volatility and compatibility with nonpolar injection liners. For highly polar columns, hexane remains standard.
  • HPLC/UPLC (normal phase): hexane/IPA or hexane/EtOAc blends.
  • Sample prep/extraction: n-hexane or MTBE for lipids; avoid highly protic solvents that can promote hydrolysis during long storage.

• Comparison (literature-based):

  • Hexane vs isooctane: isooctane offers slightly higher oxidative stability and lower volatility; hexane provides lower viscosity and faster evaporation.
  • Toluene: higher boiling point—useful when elevated inlet temps risk evaporative losses; less ideal for routine GC calibration due to solvent peak tailing.

• Practical tips:

  • Filter solutions (PTFE syringe filter) if particulates form on cooling.
  • Use amber vials and minimize headspace for unsaturated ester solutions; consider inert gas blanket.
  • Verify solvent purity (residual peroxides/UV background) when coupling to MS/UV detectors.

Storage and Reconstitution

• Item-specific storage (from Product Data):

  • Storage Conditions: Room temperature
  • Shipped In: Normal

• Appearance: Not specified for this item; refer to CoA/Spec Sheet.

• General best practices (literature/industry guidance; not specifications):

  • Store tightly closed in amber glass to limit light exposure; unsaturated esters are susceptible to slow autoxidation.
  • Minimize headspace or blanket with inert gas (N2/Ar) for long-term stability, particularly for working solutions.
  • Avoid repeated heating/cooling cycles; if partial solidification occurs (for higher-saturated content), warm gently to dissolve, then mix thoroughly.
  • Keep away from strong acids/bases and oxidizers; avoid prolonged exposure to air at elevated temperature.

• Reconstitution/preparation of solutions:

  • Prepare stock solutions in n-hexane or isooctane at known concentrations using analytical balances.
  • For GC work, use low-oxygen solvents and freshly opened vials; verify baseline cleanliness before quantitation.

• Shelf life: Not specified for this item; refer to CoA/Spec Sheet. For critical assays, verify stability by periodic re-analysis of retention time and response.

For research use only.

Structure and Identity

Analytical standard of long-chain fatty acid ethyl esters, provided under the name “Ethyl octadecanoate (trans-11)/ethyl isooleate.” The listing indicates a C18 ethyl ester isomer pair commonly used in lipid analytics.

• Item-specific facts (from Product Data):

  • SKU: E1509237
  • Grade: Analytical standard
  • Storage: Room temperature; Shipped: Normal
  • No CAS, SMILES, InChIKey, molecular formula, or MW are specified for this item.

• Literature identity data (for context; typical values for related components, not specifications for this item):

  • Ethyl stearate (ethyl octadecanoate, saturated) — Formula: C20H40O2; MW ≈ 312.53 g/mol; SMILES: CCOC(=O)CCCCCCCCCCCCCCCC; InChIKey: QZBJJHBLFQWABD-UHFFFAOYSA-N.
  • Ethyl octadec-11-enoate (trans-11 C18:1 ethyl ester) — Formula: C20H38O2; MW ≈ 310.52 g/mol; includes a trans double bond at Δ11.
  • Ethyl isooleate (commonly used term for a C18:1 ethyl ester isomer; literature often cites Δ9 isomer “ethyl oleate” with Formula C20H38O2, MW ≈ 310.52 g/mol; isooleate may denote positional/trans isomer).

• Structural features (general):

  • Long, linear aliphatic chain (C18) terminating in an ethyl ester functionality (–COOEt).
  • One isomer contains an internal C=C double bond (isomer/geometry varies by nomenclature; “trans-11” indicates an E-alkene at C11–C12).
  • The second name suggests a related C18:1 ethyl ester isomer (“isooleate”); the pair is suited for chromatographic resolution of positional/geometry isomers.

Note: Exact composition/ratio and identifiers for this catalog item are not specified; refer to the CoA/Spec Sheet for definitive identity information.

Synthetic Utility

While sold as an analytical standard, the underlying chemistry of C18 ethyl esters and C18:1 ethyl esters provides instructive synthetic utility (literature context):

• Functional group handles:

  • Ester group: amenable to hydrolysis (acidic or basic) to yield the free fatty acid; transesterification (acid/base or enzymatic) to other alkyl esters or glycerides; reduction (LiAlH4, DIBAL-H to aldehyde at low temperature) to corresponding alcohols.
  • Internal alkene (for unsaturated isomer): hydrogenation to saturated ester; epoxidation (m-CPBA), dihydroxylation (OsO4/NMO), or metathesis/cross-metathesis.

• Retrosynthetic value:

  • Ethyl esters serve as protecting and activating groups for fatty acids, improving volatility for GC and facilitating purification.
  • Positional/geometric isomer standards are critical for assigning double-bond locations via derivatization strategies (e.g., DMDS adducts) and confirming mechanistic outcomes in isomerization or metathesis studies.

• Methodological notes:

  • Enzymatic transesterification (lipases) affords mild, selective conversion to structured lipids; rate depends on double-bond position and geometry.
  • Radical allylic functionalization or Wacker-type oxidations can differentiate C18:1 isomers, informing catalyst/ligand choice in homogeneous catalysis research.

These synthetic considerations support the compound’s value in method development, mechanism elucidation, and standards-based verification of long-chain ester chemistry.

Target Specificity

Not applicable. This product is a chemical analytical standard, not a biological targeting reagent (e.g., antibody, probe, or inhibitor). No antigen, epitope, or isotype information applies.

Frequently Asked Questions

How should this product be stored?

Store at room temperature.

What is the purity of this product?

This product is supplied at ≥99% purity (chemical assay). Lot-specific values are stated on the Certificate of Analysis.

What does analytical standard mean?

analytical standard is a defined analytical purity tier suitable for quantitative analytical methods. It specifies a minimum assay percentage, controlled limits on common impurities (water, heavy metals, residue on ignition), and lot-to-lot consistency. analytical standard is one of several purity tiers — choose based on the sensitivity and regulatory requirements of your method.

How is this product shipped?

This product ships under standard ambient conditions. No temperature-controlled packaging is required.

What documentation is provided?

Available product documentation, including Certificates of Analysis (COA), Safety Data Sheets (SDS), and specification sheets, is shown in the product document area. Document availability and access follow the current site policy.