| CAS No. | 33949-18-7 |
| Molecular Formula | C4H4N5O2 |
| Molecular Weight | N/A |
| Category | Pharmacopoeial Impurity Standards / EP Impurities |
| Availability | In Stock |
Compared with other compounds in its class, the molecular weight of 251.17 g/mol gives Ribavirin Impurity 25 distinctive chromatographic separation conditions and mass-spectrometry parameter settings.
Ribavirin Impurity 25 (CAS 33949-18-7) is a certified pharmaceutical impurity reference standard with the molecular formula C4H4N5O2HO4S and a molecular weight of 251.17 g/mol.
Owing to a carbohydrate-derived structure, an amide group, a sulfone group, Ribavirin Impurity 25 is typically off-white to pale yellow crystalline powder. Its solid-state physicochemical attributes — including a molecular weight of 251.17 g/mol — guide the selection of appropriate sample preparation and analytical techniques. Nitrogen-containing functional groups confer excellent ionization efficiency in positive-ion electrospray (ESI) mode, making the compound well suited to LC-MS/MS analysis.
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 | C4H4N5O2 HO4S |
| Molecular Weight | 251.17 g/mol |
| Purity | 97%+ |
| Storage | Store at 2-8°C, protect from light, keep sealed and dry |
| Solubility (reference) | Soluble in methanol, ethanol, DMSO, water |
| Stability | May oxidize slowly on prolonged air exposure; Light-sensitive; avoid direct strong light; Hygroscopic; reseal immediately after opening |
| Degree of Unsaturation (DBE) | 5.0 |
| UV Absorption | UV-absorbing |
| CAS Registry Year (est.) | 1966 |
| Nitrogen Atoms | 5 |
| Sulfur Atoms | 1 |