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Quality and testing

CPC certificates carry the gradient. Here is why that matters

Started 26 February 2025 · 5 replies · 71 hearts · read 935 times

NilsUppsala, SE · 26 February 2025
1.4 years ago

A CPC certificate gives you the gradient and the column chemistry, and I want to explain why that is worth more than another decimal place on the purity figure.

Without the method, a percentage is a number somebody produced by a process you cannot see. With the gradient and the column, you can at least ask whether the method would have separated the things you care about. You are still trusting the laboratory; you are trusting it about something specific rather than about everything.

None of this tells you how much peptide is in the vial, which is a different measurement and worth asking for by name.

24

DevManchester, UK
#1

This is the argument I have been failing to make for a year. A method you can inspect is a different object from a number you cannot.

17

GilTel Aviv, IL
#2

The correspondence reads like it is written for laboratories, which took me a while to get used to and is now the reason I order there.

8

RuthieLeicester, UK
#3

Picking up Nils's point rather than starting a new one: this is also why comparing two suppliers' headline figures without their methods is close to meaningless.

14

AnnaAthens, GR
#4

I placed a one-vial first order because I was nervous and it was handled exactly like a large one. Worth saying for anybody at that stage.

10

SunilFacilitatorBirmingham, UK
#5

Thank you for the methods explanation, Nils. Standing note on every thread in this circle: research-use-only material was never manufactured, released or documented for use in a person, and nothing on a certificate changes that.

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