SS-31 Purity & COA: How PX1 Verifies Every Lot

At a glance: SS-31 COA purity verification

PX1 Research enforces strict analytical standard operating procedures for every batch of SS-31 produced and distributed. Each lot is assigned a unique tracking number tied directly to its third-party testing documentation, ensuring full chain-of-custody transparency from synthesis to laboratory delivery.

Our analytical validation protocol requires reverse-phase high-performance liquid chromatography (RP-HPLC) to establish peptide purity at or above 98.0%, liquid chromatography-mass spectrometry (LC-MS) to confirm exact molecular weight, and chromogenic Limulus Amebocyte Lysate (LAL) testing to quantify bacterial endotoxin levels. We also conduct amino acid analysis (AAA) to measure net peptide content accurately.

All analytical data are made available directly to researchers prior to acquisition. Orders placed before 3:00 PM EST ship the same business day from our climate-controlled fulfillment facilities in California and Arizona, arriving with physical lot documentation and digital verification access.

What is SS-31 (Elamipretide) in preclinical research?

SS-31, also known in scientific literature as elamipretide or Szeto-Schiller 31, is a synthetic tetrapeptide with the amino acid sequence D-Arg-Dmt-Lys-Phe-NH2. It belongs to a specialized class of cell-permeable, mitochondrion-targeted small molecules designed to interact selectively with cardiolipin, an essential phospholipid located exclusively within the inner mitochondrial membrane.

In preclinical model systems, researchers utilize SS-31 research compounds to investigate mitochondrial bioenergetics, electron transport chain efficiency, reactive oxygen species (ROS) attenuation, and membrane structural dynamics. Because ss31 targets cardiolipin via electrostatic and hydrophobic interactions, maintaining precise peptide structure and chemical purity is paramount for reproducible experimental outcomes.

Impurities introduced during peptide synthesis—such as deletion sequences, incomplete deprotection byproducts, residual trifluoroacetic acid (TFA), or organic solvents—can alter cardiolipin binding kinetics and yield artifacts in cell culture and isolated mitochondrial assays. Consequently, obtaining fully characterized research material with a complete third-party COA is a prerequisite for rigorous scientific inquiry.

The PX1 analytical stack: How we verify every SS-31 lot

To ensure uncompromising batch-to-batch consistency for institutional buyers and academic laboratories, PX1 Research implements a multi-tier analytical testing stack. We do not rely on manufacturer self-certifications; every lot is independently analyzed by accredited ISO/IEC 17025 contract laboratories in the United States.

1. Reverse-Phase High-Performance Liquid Chromatography (RP-HPLC): HPLC is the primary method for quantifying peptide purity. By passing the dissolved peptide through a hydrophobic C18 stationary phase under an acetonitrile/water gradient, impurities and closely related deletion sequences are separated and detected via UV spectrophotometry at 214 nm and 280 nm. PX1 requires an RP-HPLC purity threshold of ≥98.0% for all SS-31 lots.

2. Electrospray Ionization Mass Spectrometry (ESI-MS): While HPLC confirms chemical purity, MS confirms exact molecular identity. The theoretical monoisotopic mass of SS-31 (C32H49N9O5) is verified by measuring mass-to-charge ratios (m/z) in positive ion mode. This step eliminates the risk of cross-contamination or mislabeled amino acid sequences.

3. Net Peptide Content via Amino Acid Analysis (AAA) & Nitrogen Determination: Lyophilized peptide cakes contain moisture and counter-ions (such as acetate or TFA). HPLC purity reflects the proportion of target peptide relative to peptide impurities, not the total weight of active peptide in the vial. AAA quantifies the exact weight percentage of actual peptide material, allowing researchers to calculate precise molar concentrations for quantitative in vitro experiments.

4. Bacterial Endotoxin Quantification (LAL Assay): Endotoxins (lipopolysaccharides from Gram-negative bacteria) trigger inflammatory signaling cascades in cell culture and animal models, corrupting biological assays. PX1 subjects every lot of SS-31 to kinetic chromogenic LAL testing to guarantee endotoxin levels remain strictly below <0.05 EU/mg.

5. Sterility Assessment and Fill Volume Consistency: Automated aseptic filling equipment packages lyophilized SS-31 under ISO Class 5 cleanroom conditions. Finished vials undergo gravimetric fill verification and sterility testing to prevent microbial contamination during shelf storage.

6. Retained Sample Archiving: PX1 stores representative vial samples from every single lot under -80°C conditions for a minimum of two years. This allows retrospective re-analysis if a client lab reports anomalous research results or requires long-term comparative verification.

How to read an SS-31 Certificate of Analysis (COA)

A Certificate of Analysis is a legal and technical document detailing the empirical test results of a specific chemical lot. Reading a COA accurately ensures that your research team is working with material that meets strict experimental controls.

First, locate the Header Information. This section displays the product name (SS-31 / Elamipretide), CAS number (736992-21-2), lot number, date of synthesis, and date of analysis. Verify that the lot number printed on your vial label matches the lot number on the COA exactly. Discrepancies here indicate a failure in chain-of-custody tracking.

Second, examine the HPLC Chromatogram. The COA must include a full high-resolution trace showing the main peak and all minor baseline integration peaks. The main peak retention time should correspond to reference standards, and the integrated area under the curve (AUC) percentage represents chemical purity. Look for sharp, symmetrical peak geometry without significant shoulder peaks, which denote truncated peptide impurities.

Third, review the Mass Spectrometry Data. The spectrum must exhibit a clear primary peak corresponding to the calculated molecular weight of SS-31 (639.8 g/mol for the free base, or adjusted for ion adducts). No secondary mass peaks exceeding background noise thresholds should be present.

Fourth, check the Endotoxin and Physical Parameters. Verify that the endotoxin result is explicitly reported in EU/mg rather than marked as 'passed' without quantitative data. Confirm that physical appearance (typically a white to off-white lyophilized powder) and solubility metrics match your experimental preparation protocols.

Why endotoxins and counter-ions disrupt mitochondrial assays

Mitochondrial research requires extraordinary chemical purity because isolated mitochondria and primary cell cultures are exquisitely sensitive to external stressors. Bacterial endotoxins activate Toll-like receptor 4 (TLR4) pathways in cellular models, inducing endogenous ROS production and altering mitochondrial membrane potential independent of peptide action.

If an unverified SS-31 lot containing elevated endotoxin levels is introduced into a microplate assay measuring mitochondrial oxygen consumption rate (OCR) or ATP production, the biological response will reflect endotoxin-induced cell stress rather than the target peptide's interaction with cardiolipin. This invalidates baseline control data and leads to unrepeatable experimental published findings.

Similarly, residual counter-ions such as trifluoroacetic acid (TFA)—a common reagent used during cleavage and HPLC purification—can exert cytotoxic effects at millimolar concentrations. PX1 Research utilizes salt-exchange protocols during processing to reduce residual TFA levels, providing high-purity ss-31 coa purity verified compounds suitable for sensitive cellular bioenergetic work.

Supplier comparison: PX1 Research vs. standard vendor practices

When procuring research compounds for competitive grant-funded research or high-throughput screening, selecting an established supplier requires evaluating analytical standards across clear, verifiable criteria:

Purity Verification Standard: PX1 Research requires third-party RP-HPLC testing achieving ≥98.0% purity for every lot, with full raw chromatograms publicly accessible. Standard vendors frequently supply generic or batch-level COAs exceeding 95% without individual lot testing.

Identity Confirmation: PX1 Research performs LC-MS electrospray mass spectrometry on every batch to confirm exact molecular weight. Standard vendors often rely on vendor-declared synthesis specs without independent spectroscopic confirmation.

Endotoxin Testing (LAL): PX1 Research conducts quantitative kinetic LAL testing on every lot, verifying levels <0.05 EU/mg. Standard vendors rarely test for endotoxin content, risking cell culture contamination.

Sourcing and Synthesis: PX1 Research utilizes domestic US peptide synthesis and ISO Class 5 sterile filling suites. Standard vendors frequently re-package imported bulk powder with unknown quality controls.

Lot Traceability: PX1 Research maintains unique lot tracking matching vial labels directly to analytical reports, backed by retained -80°C archive samples. Standard vendors often ship vials with unlinked or generic batch numbers.

Fulfillment & Delivery Speed: PX1 Research dispatches orders same-day (M–F before 3 PM EST) from California and Arizona facilities in cold-chain compatible packaging. Standard vendors often drop-ship or take 5–10 business days with untracked transit.

Red flags when evaluating SS-31 peptide vendors

The peptide market contains numerous resellers that prioritize low cost over analytical rigor. Recognizing red flags during vendor evaluation prevents wasted grant funding and ruined research studies.

Avoid suppliers that provide 'representative' or static COA images on their product pages where the lot number, analysis date, or lab headers are blurred, redacted, or missing entirely. A legitimate vendor provides unredacted, downloadable PDF certificates corresponding specifically to the inventory currently being shipped.

Be cautious of vendors that do not publish HPLC chromatograms or MS spectra, offering only a summary table with numerical purity figures. Numerical tables without raw analytical data cannot be independently verified and are frequently fabricated.

Watch out for sellers making clinical, therapeutic, or human dosing claims. Suppliers that market peptides for personal consumption or human injection operate outside compliance boundaries and routinely compromise on sterile laboratory manufacturing controls. Legitimate research vendors restrict all sales strictly to in vitro and laboratory preclinical application.

Finally, scrutinize vendors that lack domestic physical inventory or operate solely through third-party drop-shipping brokers. Unregulated international transit exposes sensitive lyophilized peptides to extreme heat cycling, degrading peptide integrity prior to arrival at your laboratory.

Related mitochondrial compounds in preclinical research

SS-31 is frequently studied alongside other mitochondrial-active molecules and metabolic research tools to evaluate synergistic pathways in bioenergetics and cellular longevity models.

Researchers studying mitochondrial signaling often incorporate MOTS-c peptide compounds, a mitochondrial-derived peptide involved in metabolic homeostasis and nuclear gene expression regulation. Combining SS-31 with mitochondrial-targeted molecules provides a comprehensive framework for mapping organelle function.

Additionally, intracellular NAD+ depletion models frequently utilize NAD+ research formulations alongside SS-31 to investigate sirtuin activation, oxidative stress response, and sirtuin-mediated mitochondrial biogenesis pathways in cellular assays.

Explore our complete collection of verified reagents by browsing our full catalog of research peptides, or review technical documentation across our specialized research portal for updated analytical methodology.

Ordering SS-31 from PX1 Research

When you select PX1 Research as your peptide supplier, you receive laboratory-grade reagents designed specifically to satisfy strict academic and institutional research parameters.

Each order of SS-31 includes high-purity lyophilized powder packaged in sealed, borosilicate glass vials protected against atmospheric moisture and ambient light exposure. Vials are clearly labeled with the compound identity, exact mass (e.g., 10 mg), and individual lot tracking number corresponding to its online COA.

Orders submitted before 3:00 PM EST Monday through Friday ship same-day from our dual fulfillment centers in California and Arizona. Expedited, fully tracked domestic shipping ensures your shipment arrives quickly and intact, maintaining chemical stability throughout transit.

Our customer support team consists of knowledgeable technical specialists capable of providing lot documentation, answering analytical inquiries, or assisting institutional purchasing departments with tax-exempt or bulk orders. For large-scale studies requiring custom lot sizing or batch reservation, visit our wholesale peptide procurement section.

Ready to advance your mitochondrial research with batch-verified reagents? You can order 10 mg vials of SS-31 directly from our inventory for immediate dispatch.