Kynurenic-3,5,6,7,8-d5 Acid | CAS 350820-13-2

OVERVIEW  of  Kynurenic-3,5,6,7,8-d5 Acid | CAS 350820-13-2

Kynurenic-3,5,6,7,8-d5 Acid | CAS 350820-13-2is a stable, isotopically labelled analog of kynurenic acid used primarily as an internal standard for quantitative bioanalytical assays. The five deuterium atoms (D5) are incorporated at aromatic/alkyl positions to provide a +5 Da mass shift relative to native kynurenic acid, enabling unambiguous distinction by high-resolution mass spectrometry (HRMS) or tandem MS (LC–MS/MS) while preserving near-identical chemical behaviour during extraction, chromatography and ionisation. ResolveMass Laboratories supplies this material at high isotopic enrichment and chemical purity for reliable method development, validation and routine quantitation.

CHEMICAL INFORMATION

• COMMON NAME: Kynurenic-3,5,6,7,8-d5 Acid

• SYNONYMS: 4-Hydroxyquinoline-2-carboxylic acid-D5 (when applicable), Deuterated kynurenic acid (D5)

• CAS NUMBER: 350820-13-2

• MOLECULAR FORMULA (nominal): C₁₀H₂D₅NO₃ (notational — deuterium labelled)

• MONOISOTOPIC MASS (D₅): ~194.07398 Da (monoisotopic)

• STRUCTURAL CLASS: Tryptophan catabolite / kynurenine pathway metabolite (isotopically labelled analog)

PHYSICAL PROPERTIES

• APPEARANCE: Off-white to pale beige solid (batch dependent)

• SOLUBILITY: Soluble in DMSO and methanol; sparingly soluble in water — solubility improves with slight base or co-solvent. For LC-MS standard preparation, methanol or aqueous methanol (≥50%) is commonly used.

• STABILITY: Stable under recommended storage (-20 °C, dry, inert atmosphere). Avoid prolonged exposure to strong acids/bases, high temperatures or light.

• ISOTOPIC ENRICHMENT: Typically supplied with high deuterium incorporation (e.g., ≥98% D on labelled positions) — see lot COA for exact value.

ANALYTICAL & APPLICATIONS  of Kynurenic-3,5,6,7,8-d5 Acid | CAS 350820-13-2

Kynurenic-3,5,6,7,8-d5 Acid is designed as an internal standard for quantitative bioanalysis of kynurenic acid in biological matrices (plasma, serum, CSF, urine, tissue extracts) using LC–MS/MS or HRMS workflows. Primary applications include:

• Stable isotope dilution assays for absolute quantitation of kynurenic acid.

• Method development and validation (linearity, recovery, matrix effects, accuracy/precision, LLOQ determination).

• Isotope tracing experiments where a mass offset internal standard is required to correct for extraction and ionisation variability.

• Calibration and quality control material for clinical-research assays targeting the kynurenine pathway.

When used in LC–MS/MS, the D5 internal standard co-elutes with the native analyte and provides robust correction for matrix suppression and sample preparation losses. Typical detection is performed in negative electrospray ionisation (ESI-) with the deprotonated molecular ion observed near m/z 193.07 ([M − H]⁻ for the D5 species). For triple-quadrupole MRM methods the D5 internal standard yields precursor and fragment ions shifted by ~+5 Da relative to native kynurenic acid; specific fragment choice should be optimised experimentally for best sensitivity.

QUALITY CONTROL & CERTIFICATION

Each lot is supplied with a Certificate of Analysis (CoA) that typically includes:

• Chemical assay by HPLC/UV or LC–MS (reported % purity).

• Isotopic enrichment (D-incorporation %) determined by MS and/or NMR.

• Water content (Karl Fischer), residual solvent analysis, and appearance.

• Batch number, recommended storage and shelf-life.

• Traceable lot information for regulatory documentation (when required).

ResolveMass recommends reviewing the CoA and verifying critical parameters (isotopic enrichment and chemical purity) against your laboratory acceptance criteria prior to use in regulated studies.

RECOMMENDED PREPARATION & USE

• Prepare a concentrated stock in methanol or DMSO (e.g., 1–5 mg/mL) and store aliquoted at −20 °C or colder to minimise freeze–thaw.

• Spike internal standard into samples before extraction to correct for losses and matrix effects. Typical working concentrations depend on expected endogenous levels; common approaches are to use an internal standard concentration near the mid-range of the calibration curve (for example, 10–100 ng/mL in plasma assays) — optimise experimentally.

• For calibration curve preparation, use unlabeled kynurenic acid for the calibration series and the D5 compound as the constant internal standard.

• Always validate MRM transitions, collision energies and chromatographic retention on your specific instrument and column; fragmentation patterns can vary by instrument type.

HANDLING & STORAGE

• STORAGE: Store at −20 °C or lower in a dry, tightly closed container protected from light. Avoid repeated freeze–thaw cycles — aliquot upon receipt for routine use.

• HANDLING: Use appropriate laboratory PPE (gloves, eye protection, lab coat). Handle in a well-ventilated area. Avoid inhalation, ingestion and contact with skin or eyes. Consult the supplied Safety Data Sheet (SDS) for full hazard, first-aid and disposal information.

SAFETY & REGULATORY

Kynurenic-3,5,6,7,8-d5 Acid is supplied for research use only (RUO) unless otherwise specified. It is not intended for human or diagnostic use outside of validated laboratory settings. Dispose of waste in accordance with institutional and local regulations. Review SDS for specific hazard classifications and recommended protective measures.

ADDITIONAL NOTES

• For regulated / GLP environments, request batch documentation and stability data if long-term supply or qualification is required.

• If you require a custom concentration, alternative isotopic labelling pattern, or a quantified solution with traceable certification, ResolveMass can provide tailored options — please include required target concentration, matrix and intended application when enquiring.

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