A supplier's purity claim provides one piece of information about a material. A third-party laboratory report provides analytical results generated by an outside laboratory. For a quality control manager, that distinction can be important when evaluating a lot.
We submit applicable lots to independent analytical laboratories and provide available laboratory reports associated with the applicable lot. This page explains what those reports may contain and how to review them.
Request a third-party CoA for the lot you plan to order
What Third-Party Analytical Testing Is
Third-party testing involves an outside laboratory analyzing a material and reporting its analytical results. An outside laboratory that is not the product seller or manufacturer can provide an additional external analytical data point for review.
The laboratory generates the analytical results independently of the supplier's internal documentation process. The specific testing performed, methods used, and information reported can vary by laboratory and material.
Why Independence Matters
External laboratory testing provides an additional source of analytical information. However, laboratory independence does not by itself establish that results are free from error, bias, sampling limitations, or other reporting constraints.
For that reason, receiving laboratories should consider the laboratory identity, analytical method, sample or lot identification, supporting data, and reported results together.
What the Report Should Show
A useful analytical report should identify the applicable laboratory, lot number, test date, analytical method, and relevant results. A summary purity value provides less context than a report that includes the underlying chromatogram and method information.
When reviewing a report, look for enough information to connect the analytical results to the specific material being evaluated.
The Core Tests and What They Tell Us
Each analytical method addresses different material characteristics. Together, complementary methods provide a broader analytical characterization of the material.
HPLC Purity
High-performance liquid chromatography can separate the principal component from detectable impurities under the conditions of the method.
In area-normalization methods, the report may express the main peak as a percentage of total integrated detector response. The chromatogram itself can provide additional context, including the presence of additional detected peaks or differences in the baseline.
A reported percentage should therefore be considered alongside the method and chromatographic data, not on its own.
Mass Spectrometry Identity
Mass spectrometry measures ion mass-to-charge ratios and provides molecular-mass information about the detected material.
Agreement between observed and theoretical molecular mass can support an identity assessment within the limits of the method. It may also reveal additional mass species not distinguished by the HPLC method.
A matching molecular mass does not, by itself, establish complete sequence or structural identity.
Peptide Content Versus Purity
Purity and peptide content describe different analytical concepts.
In a defined chromatographic method, purity may be reported as the relative area of the principal peak compared with other integrated peaks. Peptide content generally refers to the proportion of sample mass attributed to peptide under the stated analytical method.
The two measurements should not automatically be treated as interchangeable. Depending on the material and analytical approach, other components such as counterions, water, or residual salts can affect the relationship between purity and total sample composition.
Counterions and Endotoxin
Counterion identity may matter for some experimental methods and assay conditions. The salt form associated with a lyophilized material can therefore be important for understanding its composition.
For some cell-based research, endotoxin data may also be relevant because endotoxin can affect biological readouts.
Whether these measurements are necessary depends on the material, intended research application, and laboratory requirements.
How to Read a Third-Party CoA
A CoA rewards a short, consistent review. We suggest the following order:
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Confirm that the lot number matches the vial in hand.
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Confirm the testing laboratory and test date.
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Compare observed and theoretical molecular mass where reported.
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Inspect the HPLC chromatogram rather than reviewing only the reported percentage.
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Note the stated analytical method and relevant testing conditions.
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Check whether the report includes peptide content, endotoxin, or other applicable measurements.
If an expected item is missing, ask the supplier for clarification. A well-documented report should make the applicable test information clear.
Ask our team to walk your group through a sample CoA.
Limits of Any Single Test
No single assay establishes that a material is appropriate for every experiment.
HPLC results can be affected by chromatographic resolution and may not distinguish components that co-elute under the selected conditions. Mass spectrometry provides molecular-mass information but does not by itself establish every aspect of sequence or structure.
Reading multiple analytical methods together provides broader information, while a receiving laboratory may conduct its own confirmatory checks based on its research requirements and institutional procedures.
How We Use Third-Party Testing
We incorporate third-party analytical documentation into our quality-control and documentation process for applicable lots.
We submit applicable lots to independent analytical laboratories and provide available laboratory reports associated with the applicable lot. We review lots against our documented acceptance criteria before release.
We also retain applicable analytical documentation in accordance with our recordkeeping practices. Where retained, historical lot reports can be requested for later review.
Linking the report to the lot number helps preserve the connection between the material and its analytical record.
What Procurement Teams Gain
Independent analytical reports give procurement teams an additional documented source of information when evaluating research materials. They can also provide researchers and quality personnel with analytical records for internal documentation and review.
The value of the report comes from being able to connect its results to the specific lot, understand the methods used, and evaluate the reported data within its limitations.
Order lot-documented research materials with available independent analytical reports.
Our products are intended for laboratory research use only. They are not intended for human or veterinary use.