The specific side-products of making a 16-residue peptide, and what a purity percentage leaves out

Published 26 October 2026 · REVIVE LAB UAE Research Desk · 5 min read
Each coupling in solid-phase synthesis is slightly incomplete, so a fraction of chains miss a residue and become deletion sequences one residue short, with masses lower by that residue. Protecting groups on side chains — tert-butyl on tyrosine and glutamate, trityl on glutamine, Pbf on arginine — may not be fully removed, leaving adducts heavier than the parent. The two methionines oxidise during synthesis and cleavage. Residues can racemise during activation, giving diastereomers of identical mass. A purity of 98 per cent by HPLC at 214 nanometres means the main peak is 98 per cent of the detected peptide area under those conditions; it does not count water, counterion or anything the method does not resolve.

The impurity classes

Deletions: sixteen possible single deletions, most eluting close to the parent. Incomplete deprotection: adducts of 56 daltons for tert-butyl, 252 for Pbf, which elute later because the groups are hydrophobic. Oxidation: plus 16 and 32, eluting earlier. Racemisation: same mass, usually co-eluting or nearly so, invisible to the standard method. Truncations from premature termination. Each class has a characteristic mass signature that assigns it.

Purification by preparative HPLC removes most of these; what remains is reported.

What the percentage covers

Area percentage at one wavelength under one method. Impurities that co-elute are counted as parent; impurities that do not absorb at 214 are not counted at all; and the peptide content of the vial — mass of peptide over gross mass — is a separate figure that accounts for water and counterion. Two 98 per cent figures from different methods are not the same statement.

A certificate that states the method and the wavelength has told you what the number means.

For this peptide

The oxidation line is the one to read, because of the two methionines and the tryptophan, and the deprotection adducts matter because of the arginines and tyrosines. The batch certificate for the pack reports under its stated method.

MOTS-c is supplied by REVIVE LAB UAE for laboratory research use only, with identity by mass spectrometry and purity by HPLC for the batch. It is not for human or veterinary use, and no dosing, administration or protocol guidance is provided.

What it costs

FormatStrengthPriceAvailability
MOTS-c Pack40 mgAED 950In stock

Delivery is AED 40 flat and free on orders over AED 700. Payment is cash on delivery anywhere in the UAE, or USDT (TRC20) in advance, which takes 5% off the order total.

Frequently asked

The impurity classes?

Deletions: sixteen possible single deletions, most eluting close to the parent. Incomplete deprotection: adducts of 56 daltons for tert-butyl, 252 for Pbf, which elute later because the groups are hydrophobic. Oxidation: plus 16 and 32, eluting earlier. Racemisation: same mass, usually co-eluting or nearly so, invisible to the standard method. Truncations from premature termination. Each class has a characteristic mass signature that assigns it.

Does REVIVE LAB UAE provide dosing guidance?

No. REVIVE LAB UAE supplies research materials and provides no dosing, administration or protocol guidance of any kind. Every product is sold for laboratory research use only and is not for human or veterinary consumption.

How fast is delivery in the UAE?

Stock is held in Dubai. An order confirmed before 4 PM Dubai time is dispatched the same working day, reaching Dubai and Abu Dhabi the same day and the remaining emirates within 24 hours. Delivery is AED 40 flat and free over AED 700.

MOTS-c Pack — in stock, dispatched from Dubai
HPLC-verified, lot certificate on every carton, 24-hour delivery nationwide. Browse the catalogue → All peptides UAE

Related reading

Supplied for laboratory research use only. Not for human or veterinary consumption. REVIVE LAB UAE provides no dosing, administration or protocol guidance.