D.N.

Chemist, microbiologist, horse stall cleaner.

[D.N. @Dustin_Newman]

the salt form is the piece that gets skipped a lot and it explains why two labs can both say 99.8% pure and still give you different numbers for how much is actually in the vial.
We run into this all the time at @Vanguard_Lab with our preservative testing. The HPLC method calibrates on the free acid forms because that's what the detector picks up. Then we convert to the real salt using the molecular weight ratio from the SOP.
Sodium benzoate is 144.10 g/mol and benzoic acid is 122.12 g/mol, so the factor works out to about 1.18. If the instrument reads 500 ppm on the acid side, you multiply by 1.18 and get 590 ppm of the sodium salt in the actual sample.
Peptides are no different. The counterions like TFA or acetate add weight that isn't peptide. Two labs can get the same chromatographic purity and still report different net peptide content depending on whether they corrected for the salt and water properly.
That's the main reason we always ask what salt form it is and what the CAS number is before we even choose a standard. Get that part wrong and the rest of the calculation is off from the start.
It's one of those details that our critical for accurate analysis.

[D.N. @Dustin_Newman]

Appreciate the tag. You're right, the salt form is the piece that gets skipped a lot and it explains why two labs can both say 99.8% pure and still give you different numbers for how much is actually in the vial.
We run into this all the time with our preservative testing. The HPLC method calibrates on the free acid forms because that's what the detector picks up. Then we convert to the real salt using the molecular weight ratio from the SOP.
Sodium benzoate is 144.10 g/mol and benzoic acid is 122.12 g/mol, so the factor works out to about 1.18. If the instrument reads 500 ppm on the acid side, you multiply by 1.18 and get 590 ppm of the sodium salt in the actual sample.
Peptides are no different. The counterions like TFA or acetate add weight that isn't peptide. Two labs can get the same chromatographic purity and still report different net peptide content depending on whether they corrected for the salt and water properly.
That's the main reason we always ask what salt form it is and what the CAS number is before we even choose a standard. Get that part wrong and the rest of the calculation is off from the start.
It's one of those details that separates numbers you can actually trust from ones that just look clean on a report.

[D.N. @Dustin_Newman]

@KimeraChems No free time it seems, but still ride when I can.

[D.N. @Dustin_Newman]

@hubermanlab @Vanguard_Lab Does it. Iso 17025 Accredited, we test grey market peptides, OTC pharma, Compounded prescription pharma, supplements, drinking water, etc. USP, FDA BAM, AOAC, EPA methodology. AFDO / FDA Process Authority for Aseptic Processing, Thermal processing, etc

[D.N. @Dustin_Newman]

Heavy metals aren’t intentionally used in peptide synthesis, contamination can come from raw materials, reagents, equipment & poor purification.
We've seen ~7% samples we test exceed USP heavy metal limits.
Vials/stoppers can also leach traces.
On Janoshik: if using XRF as stated its not appropriate for USP <232>/<233>. XRF lacks sensitivity for trace ppb levels in peptides. Proper method is ICP-MS.
USP parenteral PDEs (e.g. Pb ~5 µg/day, Cd ~2) show low-ppm contamination can still matter with repeated injections + batch variability. Our FDA compounding clients frequently test for metals.

[D.N. @Dustin_Newman]

@_9th_Life_ We test a lot of OTC supplements, nutraceuticals, etc at @Vanguard_Lab. Some of the worst offenders are herbal supplements found at large grocery stores and chains. Herbal supplemnts regurly fail metals testing, and oftent dont have the species of botanical listed on the label.

[D.N. @Dustin_Newman]

@hoffman_hitman @Krysia830073 @bella520zhang @Vanguard_Lab $250. Towards the bottom of the page you'll find pricing. Also routinely do a large number of USP and AOAC methods not listed on the site. If you need something specific let me know.
https://t.co/M19dTwgVIm

[D.N. @Dustin_Newman]

@Krysia830073 @bella520zhang @Vanguard_Lab No minimums. We have clients that submit 1 sample at a time and receive hundreds at a time from others.

[Vanguard Laboratory @Vanguard_Lab]

Important note for clients submitting injectable samples:
Microarray and PCR-based screens are not USP <71> sterility tests, and they are not recognized as compendial sterility methods under USP <71>, <72>, or <73>.
USP <71>, <72>, and <73> remain the official compendial sterility tests for injectable products.

Rapid or molecular methods may have research or screening value, but they should not be represented as USP sterility testing unless they fully meet the applicable USP compendial requirements and validation expectations.

Always ask the lab: “Is this a true USP compendial sterility test (<71/72/73>), or a non-compendial rapid method?”
Your compliance depends on clear answers. #USP #SterilityTesting #PharmaQC

[D.N. @Dustin_Newman]

@Sharadadadaa @alphaenu @Krysia830073 @Vanguard_Lab https://t.co/OnRzPUoRaC
Went live this week. Iso 17025 requires client confidentiality, so coas have to marked public by the client. For any not public on portal we can verify via email or phone. [email protected]
360.967.7010

[D.N. @Dustin_Newman]

@alphaenu @Krysia830073 We see altered @Vanguard_Lab COAs daily. We offer verification via online portal, email, or over the phone. Always check with the issuing lab if you have any doubts about authenticity.

[Vanguard Laboratory @Vanguard_Lab]

That “all-natural” herbal pain supplement that works surprisingly well?

Sometimes the secret ingredient is not an herb.

This overlay shows a product sample matching a diclofenac sodium standard an actual pharmaceutical that was not disclosed on the label.

Trust, but verify with chromatography. Vanguard has validated full NSAID test panels for HPLC, and LCMSMS with PPB level detection limits.

[D.N. @Dustin_Newman]

@KimeraChems @ogsvg We actually test for arginate using lcmsms, other salts like TFA, sodium, etc we use Ion Chromatography. The pH test is a good screen though, which we have used in the past.

[D.N. @Dustin_Newman]

@clarionledger For public water conversations, the methods section deserves more attention. Sampling location, first-draw vs flushed, certified method, holding time, and reporting limits can change how a result should be read.

[D.N. @Dustin_Newman]

@p_maverick_b A COA is only meaningful for the lot it represents. Once the supplier, broker, or packaging step changes, the old report does not tell you much about the current material. That is why lot-specific testing matters.

[D.N. @Dustin_Newman]

Agree with part of this: UV-HPLC alone is not a perfect identity proof for complex peptides. Orthogonal identity testing has value.

But “LC-MS” is being used way too loosely here. LC-MS, LC-MS/MS, and LC-HRMS/MS are not interchangeable. The COA you showed appears to be HPLC-UV/VIS plus single-quad LC-MS. If we agree single-quad LC-MS is mostly cosmetic, then that is not HRMS/MS impurity speciation and should not be marketed as “gold standard” peptide testing.

In regulated pharma QC, methods are selected and validated as fit-for-purpose. HPLC/UPLC remains the routine workhorse for assay, purity, and related substances because it is robust, quantitative, transferable, and validated. HRMS/MS is extremely useful for structural characterization, unknown impurity ID, troubleshooting, method development, and cases where the peptide chemistry justifies it. It is not automatically the default routine batch, release method for every peptide lot. Its also not being used to determine purity its primarily to characterize the impurities detected by HPLC UV-Vis

Isobaric/isomeric substitutions, D/L changes, positional variants, and co-eluting species still require peptide mapping via HPLC UV-Vis, MS/MS, chiral or orthogonal separation, reference standards, and defined acceptance criteria. An accurate mass number does not provide identity or impurity characterization.

A "COA with teeth" is not just one that says “LC-MS.” It should state method, reference standard, acceptance criteria, chromatographic data, and what question the test is answering.

@Vanguard_Lab , we have HPLC, LC-MS/MS, HRMS, GC-MS, ICP-MS, FTIR, amino acid analyzers, etc. We use the right tool for the question. For routine RUO peptide testing, the focus is identity, purity/assay, concentration, and, where injectable use is relevant, sterility and endotoxin. LCMSMS and HR MS come into place when impurites need profiling or initial testing is inconclusive. A decorative single-quad LC-MS chromatogram does not make a COA gold standard.

[D.N. @Dustin_Newman]

The other day someone showed me a COA(not from Kovera) for metals, said it only cost $50. Didnt list method on the COA, turned out the lab used test strips made for well water. Was not surprised that the result was non detect. Big difference between Atomic Absorbance, ICP-OES, XRF, ICP-MS test strips. Without knowing the instrumentation and LOD/LOQ a negative result doesn't mean much to me.

[D.N. @Dustin_Newman]

I'd love to tell everyone that they need to have the sample ran on the HR MS, LCMSMS, run an FTIR spectrum, maybe add some GCMS for residual solvents and while we are at it we can do AAA on the Hitachi l8900, but I think in 99% of the cases it would be a waste of money. I just wish more people would test for sterility.