Testing | AssayLine Labs

Purity

HPLC (high-performance liquid chromatography)

The sample is separated on a chromatography column and detected by UV absorbance. Purity is the main peak's share of the total peak area.

What it tells you: How much of what the detector sees is the target peptide, as a percentage.
What it does not: It does not confirm what the main peak is (that is identity) or how much peptide is in the vial (that is net content).

LC-MS (liquid chromatography with mass spectrometry)

The separated sample is passed to a mass spectrometer, which measures the mass of the main component.

What it tells you: Whether the observed mass matches the expected mass of the named peptide.
What it does not: It does not measure purity or quantity, and it does not assess sterility.

Quantitation against a reference standard

The amount of peptide in the vial is measured against a reference of known concentration.

What it tells you: How many milligrams of peptide the vial holds, compared with the amount on the label.
What it does not: It does not tell you whether the peptide is the right one or how pure it is.

Bacterial endotoxin test (LAL)

A reagent that reacts to bacterial endotoxins is used to measure how much endotoxin the sample contains.

What it tells you: The endotoxin level, usually in EU per milligram or per vial.
What it does not: It does not detect live microorganisms (that is sterility).

Culture in growth media

The sample is placed in growth media and incubated, then checked for microbial growth.

What it tells you: Whether microbial growth was detected in the sample tested.
What it does not: It covers the units sampled. It does not measure endotoxin, and results take about two weeks.

ICP-MS (inductively coupled plasma mass spectrometry)

The sample is analysed for elemental impurities such as lead, arsenic, cadmium and mercury.

What it tells you: The level of each metal tested, or that it was not detected above the stated limit.
What it does not: It reports only the elements on the panel.

GC-MS (gas chromatography with mass spectrometry)

Volatile solvents left over from synthesis and purification are separated and measured.

What it tells you: The level of each solvent on the panel, or that it was not detected above the stated limit.
What it does not: It reports only the solvents on the panel.

Water activity meter

Measures the free water in a dry powder, on a scale from 0 to 1.

What it tells you: How much water is available in the powder, which bears on its stability in storage.
What it does not: It is not the total water content, and it says nothing about purity or identity.

pH meter

Measures the acidity of the product in solution.

What it tells you: The pH of the solution as tested.
What it does not: It describes the solution only, not the peptide's purity or identity.

Which tests a lot receives is chosen when it is sent for testing. A certificate lists only the tests that were performed on that lot.

Tell us what you sell and which tests you need.