Amaia R.★★★★★
The certificate has the chromatogram on it, so I could look at the baseline and the integration marks myself instead of taking the number on faith. Nothing else in my folder lets me do that.
Sourcing reference
PolyPeptide Group (Hangzhou) Co., Ltd.
- Base
- Hangzhou
- Established
- 2006
4.7
★★★★⯨A rating here summarises what members have said about ordering. It is not a safety rating and it cannot be one.
PolyPeptide Group (Hangzhou) Co., Ltd., trading as PPG, based in Hangzhou and giving 2006 as its founding year. Members have ordered from here and reported back; what follows is theirs, not the company’s.
What members have reported
Service, timings, stock and paperwork, from people who ordered.
PPG is the supplier members describe as the one that shows its working. It runs its own solid-phase lines out of Hangzhou and sells the research catalogue direct, and the reports here read that way: technical questions answered with a figure and a unit inside a working day, quotes carrying the schedule on the face of them, and no attempt to talk anybody into a larger order than they asked for.
On the practicalities: catalogue lines dispatch within about two working days of cleared payment, regional stock covers the UK, EU, US, Canada and ANZ, and members report eleven days door to door on the Hangzhou lane against a quoted seven to fourteen. One member records a four-day dispatch delay that was notified before the quoted window elapsed rather than after it, with a revised date that then held — the sequence being the part that matters. Minimum on the catalogue is a single vial, which puts a buyer’s own verification within reach of one unit rather than a case.
The testing record, and its limits
Analysis from four independent services — Janoshik, Medutest, PeptideMeter and VendorInvestigate — exists against this catalogue, and members here have commissioned some of it themselves rather than reading only the published set. Where the two have been compared on this page the independent figures have sat within a few tenths of the published ones, which is what agreement looks like when two laboratories measure the same sample.
The thing members actually talk about is the certificate rather than the number on it. PPG reproduces the chromatogram the purity figure was integrated from, with the gradient table, the column and the detection wavelength printed beside it. That lets a reader who knows what a drifting baseline or a generously placed integration limit looks like check the figure instead of accepting it, and members have used it: one asked whether a principal peak carried a shoulder and was sent the expanded region of the trace rather than an assurance. Peptide content, water by Karl Fischer and counter-ion content appear as separate figures with units, so converting fill to working mass is arithmetic rather than assumption.
Checked against unverifiable
The left column is what somebody could confirm. The right column is what nobody can.
Dispatch and warehouses
Stock is held regionally, so an order is sent from within your own country rather than from the manufacturing site.
- Netherlands (Rotterdam) — European Union, 2-4 days
- Germany (Hamburg) — Germany, Austria, Switzerland, 2-4 days
- United Kingdom (London) — United Kingdom & Ireland, 2-3 days
- United States (California) — United States, 2-4 days
- Canada (Toronto) — Canada, 3-5 days
- Australia (Melbourne) — Australia & New Zealand, 3-5 days
Can be checked
- That the shop trades at polypeptidegroup.net, gives Hangzhou as its base and 2006 as its founding year
- That analysis from four independent services exists against this catalogue, and that members here commissioned some of it themselves
- That the certificate reproduces the chromatogram alongside the peak table, the gradient and the water content, because members have posted redacted copies
- That a supplementary certificate for a lot released nineteen months earlier was produced from records with the trace intact
Cannot be checked
- Which injection your particular vial was filled from — no certificate, reproduced trace or otherwise, can establish that
- What happened to your specific vial between manufacture and dispatch: where it sat, at what temperature, and for how long
- Sterility, endotoxin load, residual solvents and heavy metals, none of which a purity certificate reports
Questions to ask before you order
Take these verbatim. The answers, and the non-answers, are informative.
- Please send the lot-specific certificate for the code printed on my vial, including the chromatogram and the peak table.
- Is peptide content by weight reported for this lot, and by which method?
- Which regional stock will this ship from, and what is the current dispatch window from there?
- If I quote the lot code, can you supply the manufacturing record behind it rather than a summary?
Member reports
Published in full, in the words they were written in.
Tomás V.★★★★★
Gradient table and column printed next to the trace. Another lab could reproduce the determination straight off the document, which is the whole point of printing it.
Ingrid S.★★★★☆
Sent a lot out for independent analysis without saying where it came from. 98.2% against a declared 98.3%. That is inside method repeatability rather than a disagreement.
Rui B.★★★★★
I asked whether the main peak carried a shoulder, expecting a paragraph about their commitment to quality. I got the expanded region of the trace instead.
Noor A.★★★★★
Peptide content is reported separately from area percent on every certificate I hold from them. Two different quantities, and running them together is the commonest mistake in this market.
Jonas L.★★★★★
Ordered the same line across two lots deliberately to see whether the second resembled the first. A tenth of a point apart and the traces overlay.
Petra U.★★★★★
First order was a single vial because I wanted to see how the paperwork behaves before I saw how the powder behaves. Cheaper test than any assay.
Elif G.★★★★★
Water by Karl Fischer with the method named. On a lyophilised line that moves delivered mass more than another decimal place of purity would.
Marcus O.★★★★☆
The catalogue runs past three hundred and fifty lines and I have bought five of them. What I can say is about those five.
Sofie A.★★★★★
Asked for a supplementary certificate against a lot from nineteen months back. It came from their records with the trace still on it.
Hana W.★★★★★
Related substances itemised by impurity with retention times rather than collapsed into one figure. Cross-checked it against the trace and it agreed.
Bekele T.★★★★★
Lot code matched on the vial, the certificate and the invoice every time. It sounds like the floor and across suppliers it is not.
Lucía T.★★★★★
Reconstituted clear on contact, no haze and no extended swirling. Consistent with a lyophilisation that was run properly. Research use only.
Kwesi L.★★★★★
Mass spec identity alongside the chromatographic determination, so identity rests on two methods rather than one retention time.
Annika B.★★★★★
Custom sequence quoted with the schedule on the face of the quotation and finished two days inside it at the purity specified.
Ravi S.★★★★☆
They flagged a four day dispatch delay before the quoted window ran out rather than afterwards, and the revised date held.
Selin B.★★★★★
Asked about counter-ion content and had a figure with a unit back inside four hours on a working day.
David N.★★★★★
Weighed four vials from one consignment against declared fill and all were inside two per cent. Fill uniformity gets less attention than purity and is harder.
Mira P.★★★★★
Cross-checked a single lot at two independent services. They agreed with each other and with the printed figure to a tenth of a point.
Oskar M.★★★★★
Repeat determination on the same line at eleven months came back 98.0% against 98.1% first time. No drift visible in this one.
Yuki B.★★★★★
Every unit in the box carried one lot code, so the comparison I meant to make inside the consignment was the one I actually made.
Greta O.★★★★★
Cold chain held to day seven with the pack still solid, in a month where that is not a given. Tracking moved at every hop.
Tunde M.★★★★★
The printed figure was not quietly revised upward between the certificate and the commercial paperwork. Small check, worth making.
Rune C.★★★★★
Nine orders over fourteen months with no substitutions and no line going quietly out of stock after payment cleared.
Ayo L.★★★★★
Stability statement written against a named storage condition rather than a bare shelf life, so it is a claim you can evaluate.
Maya D.★★★★★
A residual-solvent screen appeared on a line whose route calls for one, without my having asked for it.
Where PPG sells
So you can read their account against this one.
PolyPeptide Group (Hangzhou) Co., Ltd. sells from its own shop. The link below is marked nofollow and sponsored. We are paid nothing for it, it is not a recommendation, and nothing on that site removes the risk described at the top of this page.