Epitalon molecular weight research starts with a number that affects nearly every downstream decision: 390.35 g/mol. For a short synthetic peptide, that value informs material verification, molar calculations, mass-spectrometry interpretation, and the defensibility of assay records. It is a compact specification, but treating it as a fixed number without confirming the supplied material can introduce avoidable analytical error.

Epitalon, also called Epithalon, is commonly represented as the tetrapeptide sequence Ala-Glu-Asp-Gly. Its short sequence makes it accessible to peptide-focused analytical workflows, yet the usual variables still apply: theoretical peptide mass, measured mass, salt or counterion form, water content, purity, and the calculation basis used by the laboratory.

Epitalon Molecular Weight Research: Core Data

The neutral molecular formula generally associated with Epitalon is C14H22N4O9. Its average molecular weight is approximately 390.35 g/mol. This average mass is typically the most practical value for preparing molar-equivalent research calculations from a stated mass of peptide.

For high-resolution mass spectrometry, laboratories often work from monoisotopic rather than average mass. The monoisotopic mass for the neutral peptide is approximately 390.148 Da. Under positive-ion electrospray conditions, expected signals can include the singly protonated ion, [M+H]+, near m/z 391.156, and the doubly protonated ion, [M+2H]2+, near m/z 196.082.

Those values are useful reference points, not substitutes for an actual identity test. Instrument calibration, adduct formation, source settings, solvent composition, and sample preparation can all shift the observed spectrum or alter relative peak intensity.

Why average mass and monoisotopic mass differ

Average molecular weight accounts for the naturally occurring isotopic distribution of elements such as carbon, nitrogen, oxygen, and hydrogen. It is generally appropriate for routine molar conversions and inventory documentation.

Monoisotopic mass uses the mass of the lightest stable isotope of each element, including carbon-12. Because mass spectrometers resolve isotope patterns and charge states, monoisotopic values are more useful when evaluating a high-resolution LC-MS result. Mixing the two values in a report is a common source of confusion, especially when a lab expects an exact-mass peak but begins with the average molecular weight.

Converting Epitalon Mass Into Moles

Molecular weight enables a direct conversion between a weighed peptide amount and the number of moles present. The relationship is straightforward:

Moles = mass in grams / molecular weight in g/mol

Using the theoretical Epitalon molecular weight of 390.35 g/mol, 1 mg of neutral peptide corresponds to approximately 2.56 micromoles. A nominal 10 mg quantity corresponds to approximately 25.62 micromoles before accounting for purity, moisture, residual solvent, counterions, or other lot-specific factors.

That distinction matters when a method requires close concentration matching across samples. A labeled vial mass does not automatically equal net peptide mass. If a material is supplied as a salt, contains residual water from lyophilization, or has a stated assay purity below 100%, the theoretical calculation is a starting point rather than the final answer.

For exploratory screening, nominal concentrations may be sufficient if all samples are prepared under the same controlled assumptions. For comparative work, quantitative LC-MS, or studies requiring precise stoichiometry, use the certificate of analysis and a validated assay basis whenever available.

Salt Form Can Change the Practical Calculation

The 390.35 g/mol figure describes the neutral Epitalon peptide itself. Commercial synthetic peptide materials may be supplied with a counterion, such as acetate or trifluoroacetate, depending on purification and finishing processes. These are not interchangeable details.

A counterion may contribute to the total measured vial mass without contributing to the neutral peptide sequence mass. As a result, calculating concentration solely from the neutral molecular weight can overstate the true peptide molarity if the product is not reported as net peptide content. The size of the discrepancy depends on the counterion identity and molar ratio, which should be documented at the lot level.

Research teams should distinguish among three descriptions: the theoretical peptide molecular weight, the salt-form molecular weight, and the assay-adjusted net peptide content. These terms can appear similar on a product page or lab record, but they answer different questions.

For purchasing and intake, request or review documentation that identifies the material form. For method development, record whether concentrations are nominal, salt-adjusted, or peptide-content-adjusted. This creates a clearer chain between the labeled material and the result generated from it.

What to Look for in Analytical Documentation

Molecular weight is most useful when paired with analytical evidence. A credible peptide research workflow does not stop at a formula on a label. It checks whether the observed identity profile aligns with the expected compound and whether purity is appropriate for the intended experiment.

For Epitalon, a practical documentation package may include an identity-oriented mass spectrum, chromatographic purity data, lot number, storage guidance, and the stated material form. HPLC or UHPLC can reveal major impurity profiles and retention consistency, while LC-MS provides an orthogonal identity check through expected mass and charge-state behavior.

A clean main peak alone is not a complete identity argument. Conversely, an expected mass signal does not establish chromatographic purity. The two methods address separate, complementary questions. Stronger research records preserve both the chromatographic result and the mass assignment alongside sample-preparation notes.

Interpreting common mass-spectrometry observations

Epitalon may produce multiple ions in an electrospray spectrum. In addition to protonated ions, sodium or potassium adducts can appear when trace salts are present in solvents, glassware, buffers, or the sample itself. The presence of an adduct is not automatically a material failure, but it should be interpreted against blanks and the complete isotope envelope.

Peptides can also show in-source fragmentation or low-level related species, particularly under aggressive source conditions. Adjusting source parameters, reducing salt exposure, and comparing intact-mass data with chromatographic behavior can help distinguish an analytical artifact from a sample issue.

The most reliable practice is to define acceptance criteria before evaluating a lot. That may include expected mass tolerance, minimum chromatographic purity, acceptable retention-time range, and documentation requirements appropriate to the research method.

Handling Variables That Affect Research Quality

Molecular weight does not determine stability by itself. Epitalon is a small peptide, but storage temperature, repeated exposure to moisture, solution pH, oxidation risk, and freeze-thaw handling can influence the quality of a prepared research sample.

Maintain clear separation between dry-material records and prepared-solution records. Record the source lot, date of preparation, solvent or buffer system, calculated concentration basis, storage conditions, and any observed change in appearance or chromatographic profile. These details are often more valuable during troubleshooting than a single endpoint result.

Avoid assuming that a nominal milligram format guarantees identical molar input between lots. For controlled comparative work, bring all materials into the same documented calculation framework. This is particularly relevant when comparing Epitalon results with other peptides that have different molecular weights, salt forms, or purity specifications.

PEPTAS SHOP positions laboratory reagents around high-purity, research-focused use, but every receiving laboratory should still review the specific product and lot documentation against its own method requirements. Product consistency supports research efficiency; independent intake controls support confidence in the data.

A Better Starting Point for Epitalon Studies

The value 390.35 g/mol is the correct foundation for most Epitalon molar calculations, provided the laboratory understands what it represents: the average molecular weight of the neutral peptide. From there, confirm whether the supplied material includes a counterion, determine whether purity or peptide-content correction is needed, and compare expected mass data with the actual analytical record.

Careful molecular-weight research is not administrative overhead. It is the small, disciplined step that makes Epitalon sample preparation easier to reproduce, analytical findings easier to defend, and future experiments easier to compare.