Analytical Methods · 10 min read
How We Verify Purity
Purity is the foundation of reproducible research. A compound that varies from batch to batch — even slightly — can introduce confounding variables that undermine months of experimental work. Halo Labs treats purity verification as a non-negotiable step in every production cycle.
Why Purity Matters
Impurities in research compounds can take many forms: truncated sequences from incomplete synthesis, oxidation products, residual solvents, or trace metals introduced during purification. Each can alter biological activity in unpredictable ways.
For a researcher, an unverified compound is an unknown variable. For a research program, it can mean wasted reagents, irreproducible results, and lost time. Rigorous purity testing eliminates that uncertainty before a vial ever leaves our facility.
Reverse-Phase HPLC
High-performance liquid chromatography (HPLC) separates a sample into its component molecules based on how each interacts with a stationary phase. Reverse-phase HPLC, the method we use, separates compounds primarily by hydrophobicity.
The resulting chromatogram shows a series of peaks. The area of the main peak relative to the total peak area gives a quantitative purity measurement, typically expressed as a percentage. Halo Labs targets a minimum of 99% purity for our research compounds.
Mass Spectrometry Confirmation
While HPLC measures purity, mass spectrometry confirms identity. Electrospray ionization mass spectrometry (ESI-MS) ionizes the sample and measures the mass-to-charge ratio of each component, producing a spectrum that must match the theoretical molecular weight of the target compound.
Together, HPLC and MS form a complementary pair: one tells you how much of the sample is the target compound, the other confirms that the target compound is actually what you intended to make.
Secondary Screens
Beyond purity and identity, we screen each batch for residual solvents using gas chromatography, for water content using Karl Fischer titration, and for bacterial endotoxin using the LAL assay where applicable. These tests catch contamination that would not appear on an HPLC trace.
The Certificate of Analysis
Every batch is accompanied by a Certificate of Analysis (COA) that documents the methods used, the results obtained, and the batch identifier. COAs are accessible through our COA Portal and are tied to the specific lot number printed on each vial.
This documentation is more than a formality — it is the auditable record that allows researchers to trace any anomaly back to a verified source.
Key Takeaways
- HPLC quantifies purity; mass spectrometry confirms identity.
- Secondary screens catch solvents, water, and endotoxin contamination.
- Every batch ships with a lot-specific Certificate of Analysis.
- Rigorous QC eliminates a major source of experimental variability.
This information is provided strictly for educational and research purposes. It does not constitute medical advice. Halo Labs products are sold for laboratory research only.