Laboratory notes
Short articles from the bench on how our tests work, what a certificate does and does not tell you, and how to compare laboratories. Written by the analysts who run the methods.
How to read our certificates of analysis
A Gold Standard certificate has a fixed structure: header, sample identity, method block, results table, chain-of-custody record and signature. Here is what each part means and how to check it.
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DAD vs VWD in HPLC: what the detector changes about a purity number
Both detectors measure UV absorbance. One measures it at a single wavelength; the other captures a full spectrum at every point of the chromatogram. That difference decides whether a purity result can tell you what the impurities are.
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ISO/IEC 17025 accreditation: what it means and what it does not
ISO/IEC 17025 is the international standard for testing laboratory competence. Accreditation is a third-party audit against it. We operate to its expectations and are not accredited; here is exactly what each phrase means.
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USP <71> sterility vs bioburden: they answer different questions
Sterility testing asks whether any viable organism is present in the units tested. Bioburden counts how many are there. For an injectable, only one of these is the release test.
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Why endotoxin is tested by kinetic chromogenic LAL, and what a PPC is
Endotoxin is the cell-wall fragment of gram-negative bacteria that causes fever in an injection even when nothing is alive. USP <85> sets the test; the positive product control is the part that proves the test worked in your sample.
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