Industrial Chemicals · Specify / Buy

How to read an industrial chemical specification

Most bad industrial chemical comparisons are documentation failures, not price failures. This guide separates what a specification, a COA, an SDS, a technical data sheet and a certificate each prove, and sets out the checks that decide whether two offers are describing the same material at all.

Before you compare two offers

The primary utility of this page. Work down it before treating two prices as comparable.

1Is it the exact same chemical identity, including salt and hydrate form?Different hydrates and salts of the same name carry different active mass per kilogram.
2Is it the same grade?Grade designations are producer-specific and are not interchangeable by name alone.
3Is the declared concentration the same, and stated the same way?A trade percent and an active-component percent are different declarations.
4Is the active basis the same for both offers?Available chlorine, active oxygen, Al2O3 and total mass are not comparable bases.
5Is the physical form the same?A solid and a solution of the same chemical are never comparable per kilogram as supplied.
6Are the relevant impurity limits stated, and are they the same limits?An undefined limit is not a passed limit.
7Is density needed to compare these offers, and is a verified value available?Mass-to-volume comparison without a stated density and temperature is guesswork.
8Which document defines acceptance — yours or theirs?Only an agreed specification can be used to reject a delivery.
9What will the COA actually verify, and against which limits?A COA reporting parameters you do not control verifies nothing you care about.
10Are packaging, net quantity and delivery terms equivalent?Net versus gross quantity and container terms move the delivered cost materially.
11Are application-specific approvals or declarations required?If a declaration is required, an offer without it is not a cheaper offer — it is a different offer.
12After all of the above, is the quoted price genuinely comparable?Price comparison is the last step, not the first, and it belongs on an active basis.

None of these questions is answered by this page for your specific product. Each one is answered by the supplier's current documents and by your own technical requirement.

What each document actually proves

Document	Proves	Does not prove	Ask for it when
Specification	The technical acceptance requirements the material is being sold against.	What any particular delivered lot actually measured.	Always — before comparing prices and before a first order.
COA (Certificate of Analysis)	The reported or tested values for one identified lot.	That the material suits your application, or that the next lot will read the same.	Per delivery, tied to the lot number on the packaging.
SDS (Safety Data Sheet)	Hazard identification, handling, storage and safety information.	Quality, assay acceptance or fitness for your process.	Always, and always the current revision.
TDS / technical data	Product properties and technical information as published by the manufacturer.	Contractual acceptance limits or regulatory approval.	When you need behaviour and property context beyond the acceptance limits.
Certificate or declaration	Only the specific statement written on its face, for its stated scope.	Anything outside that scope, however related it appears.	When an application or regulatory requirement demands that specific statement.

Document confusions that cause bad acceptance decisions

An SDS is not a quality certificate.
A COA is not a statement of suitability for your application.
A TDS is not a regulatory approval.
No single document replaces the others — they answer different questions.
A certificate never covers more than the scope printed on it.

The technical basis an offer has to state

No typical or default values are given here. Every figure belongs to the supplier's current document for the material you are actually buying.

Chemical identity
The substance itself — chemical name, and CAS number where one applies.
Why offers diverge: Trade names, synonyms and blends hide different substances behind similar wording.
Stated in: Specification and SDS section 3
Salt / hydrate form
Which salt or hydrate of the substance is being supplied.
Why offers diverge: Anhydrous and hydrated forms of the same acid or salt carry different active mass per kilogram.
Stated in: Specification and product data sheet
Concentration / assay
The declared strength of the material as supplied.
Why offers diverge: A solution and a solid of the same chemical are quoted on entirely different bases.
Stated in: Specification (limit) and COA (lot result)
Active basis
Which component the declared percentage actually refers to.
Why offers diverge: Trade percent, available chlorine, active oxygen, Al2O3 and P2O5 are different declarations.
Stated in: Specification and technical data sheet
Grade
The commercial or regulatory grade designation the material is sold against.
Why offers diverge: Grade names are not standardised between producers.
Stated in: Specification and quotation
Purity and impurity limits
The maximum permitted level of named impurities.
Why offers diverge: An offer with no stated impurity limits is not cheaper — it is undefined against yours.
Stated in: Specification (limits) and COA (lot results)
Physical form
Solid, solution, slurry, and within solids the physical presentation.
Why offers diverge: Form changes packaging, storage and the basis of the quoted price.
Stated in: Specification and technical data sheet
Density / specific gravity
Mass per unit volume of the material as supplied, at a stated temperature.
Why offers diverge: It is the only bridge between a mass-basis and a volume-basis quotation, and it is temperature-dependent.
Stated in: Technical data sheet or COA, at a stated temperature
Particle size
The size distribution of a solid material.
Why offers diverge: Two lots of identical assay can behave completely differently in handling and dissolution.
Stated in: Specification and COA where it is a controlled parameter
Packaging
Container type, net quantity and pallet configuration.
Why offers diverge: Net versus gross and container returnability change the delivered cost.
Stated in: Quotation and specification
Storage conditions and shelf life
The conditions and period over which the supplier states the product holds spec.
Why offers diverge: A shorter stated shelf life changes ordering quantity, not just price.
Stated in: Technical data sheet and specification
Origin
Country of manufacture and the producing plant where declared.
Why offers diverge: Origin affects documentation, duty treatment and lot-to-lot consistency.
Stated in: Quotation, COA and shipping documents
Lot / batch identification
The traceable production unit the reported results belong to.
Why offers diverge: Without a lot reference a COA cannot be tied to the material delivered.
Stated in: COA and packaging labels
Transport classification
The declared UN number, class and packing group where applicable.
Why offers diverge: Classification changes documentation and carrier requirements.
Stated in: SDS section 14 and shipping documents
Application-specific certificates
Declarations supporting a specific application or regulatory requirement.
Why offers diverge: A certificate supports only what it states — its scope is never wider than its own wording.
Stated in: Separate declaration documents

Use this when

You have two quotations and cannot tell whether they describe the same material.
A supplier has sent an SDS in place of a specification, or a COA in place of both.
You need to define acceptance criteria before a first order or a supplier change.
An incoming lot has to be checked against something written down.

How this works

1. Establish the exact chemical identity first — name, CAS where applicable, hydrate or salt form.
2. Read the technical basis: assay, active basis, physical form, grade and impurity limits.
3. Match each question to the document that can actually answer it.
4. Work the procurement checklist before treating two prices as comparable.

What this page does not determine

It does not state which grade your process or application requires — that is your own technical and regulatory decision.
It does not supply typical or default assay, density, impurity or particle-size values for any product.
It does not interpret a specific supplier document; it explains what each document type can and cannot prove.
It gives no handling, storage-operation or emergency instruction.
Where actual handling is involved, work from the current SDS, the manufacturer's instructions, your own site procedures and qualified technical or engineering review.

Relevant Allzone products

These are catalogue identities relevant to investigate. A listing here is not a recommendation to use the material in any process, and it is not a suitability, safety or compliance claim.

Ask for a quotation or a specification

Where this comes from, and what it cannot tell you

GHS-aligned SDS structure (16-section format) as used under WHMIS in Canada
Supports: What an SDS is designed to communicate and where that information sits.
Limitation: An SDS is a hazard-communication document. It is not a quality certificate and not an acceptance specification.
Canada (WHMIS) / GHS-aligned jurisdictions · Always use the supplier's current revision
Standard commercial practice for specifications and certificates of analysis
Supports: The distinction between an agreed acceptance specification and lot-specific reported results.
Limitation: Practice varies by supplier and contract; only your own agreed specification defines acceptance.
Contract-dependent · Confirm per supplier and per contract
Transport documentation conventions (UN number, class, packing group)
Supports: That transport classification is declared documentation, distinct from quality or suitability.
Limitation: Classification is explained as documentation only; it is not transport, packing or handling instruction.
Canada (TDG) and equivalent international frameworks · Confirm against current regulation and the shipping document