In short
A supplier is qualified for a material, not in general. Qualification starts with your own written specification — identity, physical constants, analytical limits, odor against a retained standard, and the documents that must come with it — and then checks a supplier's paperwork and first lots against it. After approval, change control matters most: a supplier's change of origin, process or sub-supplier can alter a material whose certificate still reads the same.
What you will learn
- Write a raw-material specification with identity, physical, analytical and olfactory requirements
- Check a certificate of analysis and the documents behind it against that specification
- Qualify a new supplier or a new lot against a retained standard
- Set up change notification and dual sourcing proportionate to risk
Before this lesson: Evaluation in Fragrance-House Development, Specifications and Release Testing, Incoming Quality Control: Study Guide, Supplier Quality: Study Guide
Before you start
This assumes supplier quality, incoming quality control and the Regulatory track's specifications and release testing. Nothing here states a regulatory requirement for your market; check the current rules there.
The specification
| Part | Examples |
|---|---|
| Identity | Name, CAS number where it identifies the product, botanical name and part, origin, process |
| Physical constants | Refractive index, density, optical rotation, with ranges and temperatures |
| Analytical profile | GC fingerprint against a reference; ranges for key components and for restricted or declarable constituents |
| Olfactory | Conforms to the retained standard, judged blind |
| Documents | Certificate of analysis per lot, SDS, IFRA conformity certificate, allergen statement, regulatory statements for your markets |
| Storage and shelf life | Container, headspace, temperature, re-test date |
For many essential oils, an ISO standard (such as ISO 3515 for lavender) defines physical constants and a chromatographic profile, which a specification can cite rather than reinvent.
Qualifying a supplier and a lot
- Documents: check each against the specification, and check that they agree with each other (the CAS on the SDS and the COA; the allergen statement against the GC profile).
- Sample: physical constants and, where you can, GC against your reference.
- Odor: blind comparison with the retained standard, using a triangle test where a difference must be excluded; the d′ lesson sets the sample size.
- In use: the material in one key formula, compared with the current material.
- Decision: approved, approved with conditions, or rejected, recorded with its basis and date.
Change control and dual sourcing
Agree in writing that the supplier notifies changes of origin, process, sub-supplier or site. A change triggers requalification proportionate to risk. Dual sourcing — two qualified suppliers — costs qualification effort and earns it for materials whose loss or change would stop production or change a key product: often single-origin naturals and captives with one maker.
Limitations
A COA reports what the supplier tested, on their method. GC fingerprints detect gross adulteration but can miss sophisticated adulteration designed to match a profile; that is why odor and origin traceability remain specifications in their own right. For small makers, full GC on every lot is often impractical; a risk-based plan is honest where blanket claims are not.
Research application
How often does a blind olfactory comparison detect lot-to-lot changes that physical constants miss? A small maker's records, kept systematically for a year, would answer that for their own materials.
Practical exercise: Qualify one material from two suppliers
- Write a specification for one material you use, citing an ISO standard where one exists.
- Obtain the documents from two suppliers for that material. Check each against your specification and against each other.
- Compare the two suppliers' samples blind against your retained standard, with at least three people.
- Record a qualification decision for each, with conditions and the change-notification agreement you would ask for.
You have done this well if the specification existed before you saw either supplier's paperwork, every document discrepancy is listed, the olfactory comparison was blind, and each decision cites its evidence and says what would trigger requalification.
Common mistakes
- Adopting the supplier's specification as yours.
- Treating a COA as proof of conformity. It is one lot, on their method.
- No retained standard. Then odor conformity has nothing to be compared with.
Safety
Handle new samples as their SDS directs, and follow the safe handling lesson; evaluate on strips.
Key terms
- Raw-material specification
- The written requirements a material must meet to be accepted: identity, physical constants, analytical limits, odor against a standard, and the documents that must accompany it.
- Certificate of analysis
- A supplier's statement of test results for one lot. It is checked against your specification; it does not replace it.
- Approved supplier list
- The suppliers qualified for a material, with the date and basis of each approval, consulted before any purchase.
Knowledge check
Written and reviewed by the RUŌOD Lab team. This is general education, not legal, regulatory, medical or safety advice. Example dilutions and exercises are for learning, are not validated products, and have not been safety-assessed. Completing a lesson confers no qualification. How we check these lessons.