Catalogue / Somatropin
Somatropin
Also written as Recombinant human growth hormone, rhGH, hGH 191aa.
A 191 residue recombinant protein with two disulfide bridges, expressed rather than synthesised, and the compound where the dimer question matters most.
| Class | Recombinant proteins |
| Determination | Recombinant protein, content, purity and dimer |
| Price | 650 USD |
Somatropin is identified against a certified reference standard rather than against a published mass, because commercially supplied material varies in composition between suppliers. Purity is reported separately by reversed-phase chromatography at 214 nm and describes the chromatographable fraction only.
| A dimer is chemically still growth hormone. It does not show as an impurity in a reversed phase purity figure and it requires size exclusion to quantify. A purity result without an aggregate figure is incomplete for this protein. |
| Deamidated and oxidised charge variants co-elute in reversed phase and need an ion exchange or isoelectric separation to resolve. |
| The protein is supplied lyophilised with excipients that are the majority of the vial mass. Content in international units against content in milligrams of protein are different numbers and both belong on the certificate. |
Every compound fails in its own way. A generic peptide method applied without regard to these specifics produces a number that looks like a result and is not one.
Expressed rather than synthesised. The failure modes are different: aggregation, deamidation, oxidation and truncation, none of which a single purity number captures.
RP-HPLC purity, size exclusion chromatography for dimer and higher aggregate, and where required a charge-variant separation. Aggregate is reported as a separate figure because a dimer is chemically still the same protein.
Where the delivered milligram figure matters rather than the percentage, net peptide content by combustion analysis and water by Karl Fischer are added, and the certificate carries a closed mass balance instead of a single purity number.
| LC-MS identity | Measured mass |
| RP-HPLC purity | Area at 214 nm |
| Net peptide content | Milligrams |
| Water content | Karl Fischer |
| Counter-ion | Ion chromatography |
| Bacterial endotoxins | USP <85> |
What is the molecular weight of Somatropin?
No molecular weight is published for Somatropin on this page, because the composition of commercially supplied material varies between suppliers and an unverified figure on an analytical site is worse than an absent one. Identity is established against a certified reference standard at the time of analysis.
How is Somatropin tested for purity and identity?
RP-HPLC purity, size exclusion chromatography for dimer and higher aggregate, and where required a charge-variant separation. Aggregate is reported as a separate figure because a dimer is chemically still the same protein. Purity describes the chromatographable fraction only and is not the same quantity as the peptide mass delivered per vial.
What goes wrong when Somatropin is analysed?
A dimer is chemically still growth hormone. It does not show as an impurity in a reversed phase purity figure and it requires size exclusion to quantify. A purity result without an aggregate figure is incomplete for this protein.
What does Somatropin analysis cost at ANALYTON?
Recombinant protein, content, purity and dimer is priced at 650 US dollars, covering the determinations described on this page. Content, safety and elemental determinations are ordered alongside and are priced separately on the price list.
Other compounds in this class
Updated 2026-09-01. Masses computed at build, not transcribed.