| CAS No. | 83795-61-3 |
| Molecular Formula | C19H17N5O5 |
| Molecular Weight | 395.37 g/mol |
| Category | Pharmacopoeial Impurity Standards / EP Impurities |
| Availability | In Stock |
CATO supplies Pemetrexed Impurity (CAS 83795-61-3), a pharmacopoeial impurity reference standard (molecular formula C19H17N5O5, MW 395.37 g/mol) used for the identification and quantification of trace impurities in APIs.
Structurally, Pemetrexed Impurity (C19H17N5O5) contains a flavonoid core, an amide group, a hydroxyl group, an ether linkage. The molecule exhibits a degree of unsaturation (DBE) of 14.0, corresponding to approximately 14 ring(s) or double-bond equivalent(s). With a molecular weight of 395.37 g/mol, it falls into the moderately-high-molecular-weight range. The presence of an aromatic ring or conjugated system gives the compound characteristic absorption bands in the UV-Vis region, making it well suited to UV or diode-array detection (DAD).
Recommended for quantitative analysis by HPLC, GC, LC-MS/MS, or GC-MS as an external calibration standard; it can also be used for spiked-recovery experiments, LOD/LOQ determination, and LC-MS/MS multiple-reaction-monitoring (MRM) calibration.
The assigned purity is verified by mass-balance and quantitative NMR (qNMR) approaches, with the expanded uncertainty reported at a 95% confidence level (k=2). Batch homogeneity and stability are independently assessed for every lot.
| Molecular Formula | C19H17N5O5 |
| Molecular Weight | 395.37 g/mol |
| Appearance | Pale yellow to yellow crystalline powder |
| Purity | 97%+ |
| Storage | Store at 2-8°C, protect from light, keep sealed and dry |
| Solubility (reference) | Soluble in DMSO, DMF, methanol |
| Stability | May oxidize slowly on prolonged air exposure; Light-sensitive; avoid direct strong light; Hygroscopic; reseal immediately after opening |
| Degree of Unsaturation (DBE) | 14.0 |
| UV Absorption | UV-absorbing |
| Structural Features | Aromatic ring present |
| CAS Registry Year (est.) | 1980 |
| Nitrogen Atoms | 5 |