How every lot gets made

Solid-phase synthesis (SPPS)

Sequence is built one amino acid at a time on a resin support. Fmoc deprotection between couplings. Final cleavage with TFA cleaves the peptide from resin and removes side-chain protecting groups simultaneously. Crude peptide is precipitated in cold ether and lyophilized.

Equipment: automated SPPS synthesizer. Scale: 100 mg to 5 g per cycle depending on SKU.

Reversed-phase HPLC purification

Crude peptide is loaded onto a C18 prep column and eluted with a water/acetonitrile gradient containing 0.1% TFA. Fractions are collected by UV detection at 220 nm. Only fractions meeting ≥99% area purity are pooled and re-lyophilized to powder.

Bench mark: prep C18, 220 nm UV, mass-directed fractionation when available.

Mass spectrometry confirmation

Purified material is checked by ESI-MS or MALDI-TOF. We confirm the observed monoisotopic mass matches the calculated mass within ±0.5 Da. Any disagreement triggers a hold and re-run; nothing ships against an unverified mass.

Analytical HPLC for the lot certificate

A fresh analytical RP-HPLC injection is run on the finished, lyophilized material. This is the trace that gets archived as the lot COA. Integrated peak areas, retention times, gradient method, column part number, and operator initials all go on the certificate.

Released minimum: ≥99% main-peak area purity. Anything below: hold or destroy.

Endotoxin and bioburden (where applicable)

For SKUs intended for cell-culture or animal-research applications, we run a LAL endotoxin assay and report the EU/mg result on the lot certificate. Bioburden plates may be included for institutional buyer requests.

Note: these are research-grade limits, not pharmacopeial limits. Read the COA carefully.

Vial fill, label print, lot assignment

Lyophilized material is dispensed under HEPA-filtered laminar flow into 2 mL or 5 mL flint borosilicate vials, stoppered, and crimped with a colored aluminum seal (brand red for catalog SKUs). Labels print with the SKU, lot number, fill weight, manufacture date, and storage instruction. Each vial gets a tamper-evident sticker.

QC release

Two-person sign-off: analytical chemist signs the COA, ops manager signs the release. Released lots move to the cold-room (−20°C) and are picked from there when an order ships. Unreleased lots stay quarantined and cannot be picked by the WMS.

Order pack and ship

Each picked vial is packed with insulation and a freeze-pack appropriate to the destination zip-code transit time. The lot COA is printed and packed inside. Tracking emails go to the customer with a link to the public COA page for that lot at /coa/.

Retention and stability

A reserve aliquot of every lot is held at −80°C for 24 months. If a customer reports a quality issue, we can pull the reserve, re-run the analytical HPLC, and confirm whether the material on file still meets release criteria.