Precision Peptide Analysis
Industry-leading HPLC/MS peptide testing with uncompromising accuracy. Clark-Turner Scientific delivers the analytical precision your research demands.
Why Choose Clark-Turner
What We Test
Five essential tests for peptide characterization and release. Each backed by methods we've refined over years of hands-on work in the industry.
HPLC-based quantification of peptide purity and related impurities
We use reverse-phase UHPLC with optimized gradient profiles developed specifically for peptide separations. Unlike generic methods, our approaches account for the unique retention characteristics of peptide sequences—hydrophobic clustering, secondary structure effects, and TFA ion-pairing behavior.
Each peptide gets a method matched to its properties. Short, hydrophilic sequences need different conditions than long, hydrophobic ones. We've built a library of baseline methods that we fine-tune based on your peptide's characteristics, giving you better peak resolution and more accurate quantification than one-size-fits-all approaches.
Mass spectrometry confirmation that your peptide is what it should be
Identity confirmation via LC-MS using electrospray ionization. We acquire full-scan mass spectra and deconvolute the multiply-charged ion envelope to determine the intact molecular weight. For peptides with modifications, we verify the expected mass shift matches the target structure.
When sequence confirmation is needed, we run MS/MS fragmentation and analyze the b- and y-ion series. This tells you not just that the mass is correct, but that the amino acids are in the right order—critical for catching synthesis errors like deletion sequences or epimerization.
Accurate determination of active peptide in your sample
Net peptide content tells you what percentage of your sample is actually peptide versus salts, water, and counterions. This is critical for accurate dosing and formulation work. We offer multiple approaches depending on your accuracy requirements and sample constraints.
Our primary method uses quantitative amino acid analysis (AAA)—complete acid hydrolysis followed by derivatization and HPLC quantification of individual amino acids. We calculate peptide content from stable amino acids (avoiding those destroyed during hydrolysis) and cross-reference multiple residues for confidence. For faster turnaround, we also offer nitrogen-based methods and UV quantification with sequence-specific extinction coefficients.
LAL-based detection of bacterial endotoxins for injectable peptides
We use the kinetic chromogenic LAL (Limulus Amebocyte Lysate) method on a Charles River Endosafe system. This gives quantitative endotoxin levels, not just pass/fail—important for trending and process control. The cartridge-based system includes built-in positive product controls to detect interference, so you know the result is valid for your specific matrix.
Peptides can be tricky for endotoxin testing—some sequences bind endotoxin, others interfere with the LAL reaction. We've developed sample preparation approaches for common interference scenarios and will work with you if your peptide presents challenges. Every test includes spike recovery validation to prove the method works for your sample.
USP-compliant microbial testing for sterile peptide products
Sterility testing per USP <71> using membrane filtration. Your sample is dissolved and filtered through a 0.45μm membrane that captures any microbial contamination. The membrane is then incubated in growth media—fluid thioglycollate medium (FTM) for anaerobes and soybean-casein digest (TSB) for aerobes/fungi—and observed for 14 days.
We maintain a qualified cleanroom environment for sterility testing and run concurrent growth promotion and sterility controls. If your peptide has antimicrobial properties (many do), we'll validate the method with neutralization or dilution approaches to ensure we're not getting false negatives. Method suitability testing is included for new peptides.
Technical Excellence
We didn't cut corners on instrumentation. Same platforms you'd find at a top-tier contract lab—we just don't charge like one. Everything is properly calibrated and maintained by us, the people who actually run your samples.
Ultra-high performance LC with quaternary pump and DAD detector. Sub-2μm C18 columns optimized for peptide separations.
Quadrupole time-of-flight mass spectrometer for accurate mass confirmation, sequence verification, and impurity identification.
Total organic carbon analysis for cleaning validation and water quality monitoring in our sterility testing suite.
Cartridge-based LAL endotoxin detection system with kinetic chromogenic readout for rapid, quantitative results.
We've developed 23 proprietary methods specifically optimized for peptide analysis—addressing the gaps we saw in standard protocols during our years in the industry.
Who We Serve
Whether you're a startup, established company, or academic researcher, we provide the same expert analysis and personal attention.
Drug development, QC testing, batch release, stability studies
Peptide therapeutics, conjugates, process development
Grant-funded projects, publications, discovery research
CMO/CDMO support, release testing, analytical transfer
How It Works
No bureaucracy, no handoffs between departments—just a straightforward process designed to get you results fast. Most standard analyses are completed within 3-4 business days of sample receipt.
Complete our online submission form and ship your samples with our prepaid label. We accept samples Monday–Friday.
Our scientists perform rigorous HPLC/MS analysis following validated SOPs and quality protocols.
All data undergoes dual-scientist review and QA verification before report generation.
Receive your detailed COA and raw data via secure portal. Remaining sample returned upon request.
Quality Assurance
We've worked in labs where "quality" meant paperwork theater. That's not us. Quality at Clark-Turner means your results are right, your data is clean, and you can actually use what we give you.
Every analysis follows documented procedures, uses calibrated instruments, and gets reviewed before it goes out. If something's not right, we'll make it right—no excuses, no extra charge.
Not satisfied with your results? We'll re-run the analysis at no charge or refund your payment.
We sign NDAs for every project. Your data and sample information remain strictly confidential.
Professional liability insurance covers your samples. Remaining material returned upon request.
We're building toward ISO 17025 accreditation as we grow, following those standards now.
About Us
We came up through the peptide industry—working in synthesis, QC, production, fulfillment. We saw the same problems over and over: slow testing, opaque processes, labs that couldn't answer basic questions about your own samples.
So we built something different. Clark-Turner is a testing lab run by people who actually understand your business, not just the chemistry. We know why turnaround matters. We know what's actually useful in a COA. We know the questions you're going to ask before you ask them.
We're not a big corporate lab with layers of bureaucracy. We're two founders who learned this industry from the ground up, invested in serious equipment, and now do the work ourselves. When you email, you hear back from us directly.
FAQ
Find answers to frequently asked questions about our services, processes, and capabilities.
Most routine analyses (purity, identity, net peptide content) are completed within 3-4 business days of sample receipt. Endotoxin testing is similar. Sterility testing requires 14 days of incubation per USP requirements—that's just the nature of the test. For complex projects or method development, we'll provide a timeline estimate upfront.
Samples should be shipped as lyophilized powder when possible, with a minimum of 10 μg for standard analysis. Include any available documentation (structure, expected MW, synthesis method). We provide prepaid shipping labels and detailed sample submission instructions upon request. Samples requiring cold storage should be shipped on dry ice.
Yes, we offer comprehensive method development and validation services. This includes HPLC method optimization, stability-indicating method development, and full ICH Q2(R1) validation packages. We can also perform analytical method transfer from your existing methods or develop new methods from scratch.
Every analysis includes a detailed Certificate of Analysis with methodology, instrument parameters, and results interpretation. We also provide raw data files (chromatograms, spectra) so you can review the primary data yourself. If you need specific report formats for internal documentation or publications, just let us know.
We analyze a wide range of peptides from small dipeptides to larger polypeptides up to approximately 150 amino acids (20 kDa). This includes linear peptides, cyclic peptides, stapled peptides, and peptides with various modifications (PEGylation, lipidation, unnatural amino acids). Contact us for specialized requirements.
Email us at analysis@clarkturner.com or fill out the contact form on this page. Tell us what you're testing, how many samples, and any specs you need to meet. We typically respond with a detailed quote within 24 hours. For ongoing projects, we offer volume discounts and can set up master service agreements.
Certificate of Analysis
Enter the 8-character code from your analysis report to download your Certificate of Analysis.
Get In Touch
Have questions? Want a quote? Send us an email and you'll hear back from one of us personally—usually within a few hours during business days.