Piroctone Olamine COA: What 99% HPLC Does—and Doesn’t

Piroctone Olamine COA: What 99% HPLC Does—and Doesn’t—Tell a Shampoo Buyer

Article draft | Ingredexa | 26 October 2026 For a supplier-by-supplier comparison of current offers, see the piroctone olamine supplier comparison.

Quick Answer

A 99% HPLC result tells you how much of one peak was measured, not that the material is the salt you ordered. Confirm the CAS and salt identity, ask what the method actually quantifies, reconcile the ethanolamine balance with the stoichiometry, and treat the COA as a lot record rather than a brochure. Then check the sample in your own shampoo base, because raw-material release and finished-product performance are two different questions.

A piroctone olamine certificate can show “99% HPLC” and still leave a shampoo buyer with unanswered questions. Does the result measure the whole 1:1 ethanolamine salt, or only the piroctone moiety seen by that method? Is the document a specification, a typical result, or a test on the lot you will receive? And does a passing raw-material COA say anything about how the active will behave in your surfactant base?

Those are separate questions. Piroctone olamine is the monoethanolamine salt of piroctone (CAS 68890-66-4). A 2023 analytical study describes the salt as dissociating in solution and notes that its HPLC procedure detects the acidic piroctone moiety; the more polar ethanolamine is not measured as the same chromatographic peak. Finished shampoo analysis is another task again: EN 16342 describes a method for quantifying piroctone olamine in surfactant-containing cosmetics. [1,2]

For procurement, the practical rule is simple: do not approve a lot from the headline percentage. Match identity, result meaning, method, batch traceability, impurity controls and the intended formulation test. The checklist below turns that into a review you can send to a supplier or use during incoming-QC qualification.

1. Confirm that the material is the salt you intend to buy

Start with the full name, CAS number, INCI name and molecular formula across the quotation, specification, SDS, COA and package label. The expected commercial identity is piroctone olamine, CAS 68890-66-4, formula C16H30N2O3, molecular weight about 298.42 g/mol. Government and chemical database records identify it as a 1:1 compound of piroctone and 2-aminoethanol. [3,4]

A useful intake check is to compare document identifiers: supplier legal name, product code, grade, batch number, manufacture or retest date, and revision date. The COA should identify the tested lot, not just repeat a generic specification. If a trading company is involved, ask who manufactured the lot and how the batch is traceable back to that source. The answer need not be “direct factory”; it does need to be clear enough to investigate a deviation later.

2. Ask what “99% HPLC” actually measures

“HPLC purity” is not a complete analytical description. Request the method or a controlled method summary: reference standard, sample preparation, column and detector where appropriate, calculation basis, system suitability, and whether the result is area percentage or a calibrated assay. An area-normalized chromatogram can report the share of detected peaks attributable to one analyte. It does not automatically quantify water, inorganic residue, residual solvents or components the detector does not see.

The distinction is especially relevant for this salt. In the 2023 characterization paper, the authors explain that piroctone olamine dissociates into piroctone and ethanolamine in solution. Their HPLC method detects the piroctone moiety, while ethanolamine’s greater polarity means it elutes near the start rather than appearing as the same measured peak. [1] Therefore, an HPLC result for piroctone should not be casually relabeled “99% of the complete salt by mass.”

A separate supplier specification may list both “assay 98.0–101.5%” and “HPLC purity ≥99%.” Lonza’s published 2021 technical data sheet uses that combination and separately specifies 2-aminoethanol at 20.1–20.9%. These are supplier-specific fields, not universal limits. The spread above 100% in an assay range is a reminder to ask how the result is calculated and whether it is reported on an as-is, dried or reference-standard basis; it is not, on its own, evidence of fraud.

Ask the supplier to define each percentage in writing. Useful wording: “Please state whether the COA assay is a calibrated content of piroctone olamine salt, a piroctone-moiety equivalent, or another calculated result. Please identify the reference standard and whether the value is as-is or corrected for water.” If the answer is simply “HPLC 99% is purity,” the document has not yet resolved the measurement question.

3. Reconcile ethanolamine with the salt stoichiometry

Ethanolamine is not an incidental contaminant in piroctone olamine; it is the counterion in the defined salt. Based on the molecular formula and molecular weight, ethanolamine represents about 20.5% of the formula mass (61.08 ÷ 298.42, approximately 20.5%). This is a theoretical stoichiometric calculation, not a universal COA specification. Supplier ranges around 20–21% are consistent with that composition, but the lot method and result still need review. [3]

Treat an ethanolamine field as a composition check, not as a substitute for identity testing. Ask whether it is measured by a specific method, calculated, or copied from the specification. A result materially outside the supplier’s stated range deserves explanation and possibly retesting. A matching value alone cannot prove the correct salt, because multiple analytical checks are needed to establish identity and composition.

If the buyer’s own finished-product or market requirements restrict particular impurities, define those separately. Do not treat “ethanolamine 20.5%” as a safety clearance, nor infer that any other amine-related impurity is absent. The question for QA is whether the supplier has a suitable control strategy and whether the available methods are sensitive to the substances your risk assessment identifies.

4. Read the COA as a lot record, not a brochure

For every incoming lot, confirm that the COA contains actual numerical results, units, acceptance criteria and the analytical method or method reference. “Pass” can be acceptable for some qualitative identity tests, but it is weak evidence when a buyer needs to trend assay, loss on drying or a specified impurity. Check whether the document is signed or otherwise approved under the supplier’s quality process, and whether the batch number matches the physical label.

A sample COA on a website is useful for seeing what fields a supplier claims to control. It is not evidence that your shipment has those results. Likewise, a catalogue specification states an acceptance range; it does not report what happened in the batch. Keep the two documents distinct in your system: approved specification defines the limits, lot COA records the tested result.

A practical first-order document packet usually includes current specification, TDS, SDS and a representative COA; before release, collect the lot-specific COA and any required declarations. If your product needs a particular impurity statement, allergen statement, residual-solvent profile or regulatory support document, request it explicitly. Do not assume that “cosmetic grade” names a globally standardized grade or automatically includes every document your market requires.

5. Select impurity tests by risk, not by a giant checklist

The right control panel depends on route, supplier process, market, intended use and your organization’s risk assessment. Common buyer questions include loss on drying or water, residue on ignition/ash, residual solvents, elemental impurities and nitrosamines where relevant. Supplier specifications sometimes publish limits for several of these fields; that does not make any one limit a universal piroctone olamine standard.

Ask for the method, limit of quantification and whether the result is measured for each lot, periodically, or supported by process validation. A “not detected” result means little without the method’s detection capability. For residual solvents, identify which solvents are relevant to the manufacturing route rather than treating a generic statement as a complete screen. For elemental impurities, align the analytical panel with applicable requirements and the risk posed by the raw material and finished product.

For nitrosamines, avoid a reflexive pass/fail demand unsupported by a route-specific rationale. If your assessment calls for a limit, ask what analytes are included, what sample preparation and method are used, and whether the stated limit is achievable and appropriate for the intended market. The objective is a defensible specification connected to plausible hazards, not the longest list of numbers.

Sourcing candidate for buyer review

One Alibaba listing reviewed for this article is linked below as an RFQ starting point for a piroctone olamine grade. It is a sourcing route, not evidence that the material behind the COA you are holding is the same salt — the checks above still decide that.

6. Do not confuse raw-material release with shampoo assay

A raw powder COA cannot prove the concentration in a finished shampoo. The shampoo has surfactants, salts, polymers, fragrance and other ingredients that can affect extraction and measurement. EN 16342:2013 covers detection and quantitative determination of piroctone olamine, zinc pyrithione and climbazole in surfactant-containing cosmetic products over a stated range of 0.1 to 1.0 g per 100 g. The standard is about finished cosmetics; it is not a supplier qualification specification for incoming powder. [2]

If you need to confirm active content in your own shampoo, ask your laboratory whether its method is suitable for the exact matrix and target range. A method validated for a simple solvent solution is not automatically validated for a viscous, opaque or high-surfactant product. Define recovery, specificity, precision and sample preparation in the matrix that matters. Do not use the supplier’s raw-material HPLC number as if it were a finished-batch test.

The same separation applies to performance. A peer-reviewed shampoo study found that changes to surfactant-micelle behavior and polymer coacervation could affect piroctone olamine delivery and retention. That work shows why the active’s performance depends on formulation architecture; it does not certify that a particular purchased powder will perform in every shampoo. [5] Raw-material identity, formula compatibility, finished-product assay and efficacy are related but separate evidence layers.

7. Use the sample to test the problem your plant will face

Piroctone olamine is often described as poorly soluble in water, but solubility is conditional on solvent, temperature and composition. In one 2023 study, the compound showed much higher measured solubility in methanol and propylene glycol than in water; the work concerned topical pre-formulation and cannot be translated directly into a universal shampoo process. [1] A clear result in a test solvent does not establish clarity or stability in your surfactant base.

Before commercial approval, make a small, documented trial in the actual intended system. Agree a test plan with formulation and QA: use the supplier’s grade-specific addition guidance, record the premix composition and temperature, and observe dispersion, clarity or haze, precipitation, pH and viscosity at defined checkpoints. Then test the finished formula under your normal stability and packaging protocol. Keep concentration, addition order and mixing conditions in the record so a second lot can be compared fairly.

If a sample forms a clear premix but precipitates after it meets the shampoo, that is a formulation-compatibility finding, not proof that the COA is false. Conversely, a visually uniform batch does not prove active concentration or shelf stability. Route the observation to the right owner: analytical result to QC, process behavior to formulation, and specification or change history to supplier quality.

When comparing two suppliers, run the same trial at the same active-equivalent target, not at equal powder weight if their agreed assays differ. Keep the shampoo base, order of addition, shear and temperature constant; record when and where haze appears. This small control prevents a common sourcing mistake: attributing a formula difference to “quality” before checking whether the test conditions or the active dose changed.

Before approving a target for any of these fields, compare it with the supplier’s controlled specification and intended market. A vendor sample COA is a useful format example, not proof that its proposed limits are suitable for your formula or local requirements. If your internal release specification is stricter, confirm that the supplier can test against it before placing a production order; do not wait until the shipment arrives to discover that the method or limit was never agreed.

A short approval sequence for procurement and QA

A defensible first-lot decision can be made in five passes:

identity and document alignment;
clear definitions for assay and HPLC purity;
lot-specific results for agreed composition and risk-based impurities;
supplier traceability and change-control expectations;
a formulation sample trial plus finished-product method suitability where required.

Record unresolved items as open conditions rather than assuming that a marketing claim closes them.

For repeat purchases, compare more than the headline assay. Trend lot-to-lot results, moisture, impurity controls, appearance, particle-size information if it matters to your process, and trial behavior. Require advance notice of changes that could affect the material, source, site, specification or analytical method. The point of qualification is not to make one COA look perfect; it is to make the next lot predictable enough to release against a controlled decision.

A current Alibaba listing can help you request a quote or sample, but the public item page is only a sourcing lead. Confirm the seller’s legal role, exact product identity, lot documentation, pack size, minimum order, shipping basis and current terms directly before purchase. The listing below identifies piroctone olamine, CAS 68890-66-4; no claim is made here that its unshared batch COA or formulation performance has been independently verified.

References

[1] Tang et al. “Characterization of piroctone olamine for topical delivery to the skin.” International Journal of Cosmetic Science (2023). https://pmc.ncbi.nlm.nih.gov/articles/PMC10947268/
[2] EN 16342:2013, Cosmetics—Analysis of cosmetic products—Quantitative determination of zinc pyrithione, piroctone olamine and climbazole in surfactant-containing anti-dandruff products. Scope summary: https://www.iteh.eu/catalog/standards/cen/b63e663f-3f7d-4e0e-a04d-05994eacf6f1/en-16342-2013
[3] FDA Global Substance Registration System, Piroctone Olamine (UNII A4V5C6R9FB), CAS 68890-66-4. https://precision.fda.gov/uniisearch/srs/unii/a4v5c6r9fb
[4] PubChem, Piroctone olamine, CID 50258. https://pubchem.ncbi.nlm.nih.gov/compound/50258
[5] “Enhanced piroctone olamine retention from shampoo for superior anti-dandruff efficacy.” PubMed indexed article. https://pubmed.ncbi.nlm.nih.gov/36573829/
Research note: Current SERP review found supplier product pages, marketplace supplier directories, formulation content and a peer-reviewed analytical paper. Social searches surfaced anecdotal user posts about precipitation after transfer into a different base; these were treated only as user-problem signals, not technical evidence. Search-result coverage is a dated snapshot, not a complete ranking guarantee. YouTube and other video-platform searches did not surface a sufficiently credible, ingredient-specific technical demonstration to use as evidence; public forum posts were treated as anecdotal signals only.