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Buyer reference
The things worth knowing before you place the order
Grades, documentation, pack sizes and dangerous-goods classes explained in the terms a purchasing or QA team actually uses. No sign-up, no gated PDFs.
Documentation
COA, SDS and what each one is for
Two documents travel with every consignment, and they answer different questions. Confusing them is the most common reason a delivery gets held at goods-in.
Certificate of Analysis
Batch-specific. It states what was actually measured on the material you are receiving: assay, moisture, heavy metals, particle size, whatever the specification covers. It carries the manufacturer’s batch number, the test date and the analyst’s sign-off.
Use it to: accept or reject the delivery against your incoming specification, and to trace a downstream problem back to a batch.
Safety Data Sheet
Product-specific, not batch-specific. Sixteen standardised sections covering hazard identification, first aid, firefighting, handling, storage, exposure controls, physical properties, stability, toxicology, disposal and transport classification.
Use it to: write your handling procedure, set your PPE, plan storage segregation and complete your transport paperwork.
An SDS has no fixed expiry, but it must reflect current classification. If a product’s hazard classification changes in your jurisdiction, ask us for the reissued sheet rather than working from the copy in your file.
Transport
Dangerous goods classes you will meet in this catalogue
The class on the Safety Data Sheet decides the packaging, the marking and often the carrier. It is worth checking before you commit to a delivery date.
| Class | What it means | Catalogue examples | Practical effect |
|---|---|---|---|
| Class 3 | Flammable liquid | Acetone, IPA, methanol, toluene, MEK, ethyl acetate | UN-approved packaging, limits on air freight, segregated storage away from oxidisers and ignition sources. |
| Class 5.1 | Oxidising substance | Sodium persulphate, calcium hypochlorite, hydrogen peroxide, TCCA | Must be segregated from class 3 and class 8. Some carriers refuse mixed loads entirely. |
| Class 6.1 | Toxic substance | Selected plating salts and specialty intermediates | Often requires an import permit and a named consignee. Expect additional documentation. |
| Class 8 | Corrosive | Sulphuric acid, hydrochloric acid, caustic soda, ammonium hydroxide | Packing group determines container specification. Secondary containment usually required in transit. |
| Not regulated | No transport hazard | Soda ash, citric acid, kaolin, TiO2, xanthan gum | Ships as general cargo. Still needs an SDS, still needs correct storage. |
Within a class, packing group I is the highest danger and III the lowest. The group changes the container standard and sometimes the permitted quantity per package, so it appears on every quotation for a regulated line.
Packaging
Choosing a pack size
Pack size is not only a quantity decision. It changes the unit price, the handling equipment you need, and how long the material stays good once opened.
| Pack | Typical use | Handling | Once opened |
|---|---|---|---|
| 1 L / 1 kg | Trial, method development, QC reference | Hand carry | Use within weeks; repeated opening introduces moisture and contamination. |
| 5 L / 5 kg | Small-batch production, lab scale-up | Hand carry | Decant into a working bottle rather than dipping the stock container. |
| 25 L / 25 kg | Standard production pack | Two-person lift or trolley | Reseal immediately. Hygroscopic solids should go back into a sealed liner. |
| 200 L drum | Continuous or high-volume use | Drum trolley, forklift, pump or tap | Use a dedicated pump. Never leave a bung open on a solvent drum. |
| 1,000 kg bulk bag | Bulk powders and granules | Forklift or crane with a loop lift | Discharge in one operation where possible; partial discharge risks bridging and moisture ingress. |
Grades
Technical, food and electronic grade — the difference that matters
The same molecule is sold at several grades, and the grade is a statement about impurities rather than about the main component. Citric acid at 99.5% technical and citric acid at 99.5% food grade can both be 99.5% citric acid; what separates them is what makes up the remaining half a percent, and which monograph the manufacturer tested against.
Technical grade
Manufactured to a commercial specification. Assay is controlled; trace impurities generally are not, beyond whatever the process naturally delivers. Appropriate for cleaning, water treatment, metal finishing and most industrial processing.
Food grade
Tested against a food-additive monograph — typically FCC or the relevant national standard — with heavy metals, arsenic and microbiological limits specified. Carries an E number where one exists. Never substitute technical grade into a food application because the assay looks the same.
Electronic grade
Controlled for trace metals and particulates at parts-per-billion levels, because a metal ion that is irrelevant in a detergent will ruin a wafer. Packaged in materials chosen not to shed particles. Priced accordingly.
Pharmacopoeial grade
Tested against a pharmacopoeia monograph such as USP or BP. In our catalogue this applies to excipients and additives — we do not supply prescription-controlled active pharmaceutical ingredients.
Storage
Storing what you have bought
Segregate by class
Oxidisers away from flammables. Acids away from bases and from cyanides. Water-reactives away from anything wet. Segregation is not a nice-to-have — most chemical warehouse incidents start as a storage decision.
Control temperature and light
Hypochlorite loses available chlorine steadily above 25 °C. Peroxides decompose faster warm. Several organics are light-sensitive. Cool, dark, ventilated is the default unless the SDS says otherwise.
Keep powders dry
Caustic soda, calcium chloride and STPP all pull moisture from the air and cake. Reseal the liner, not just the outer bag, and keep bulk bags off a damp floor.
Contain the spill you have not had
Bunding, absorbent and the right neutraliser stocked before you need them. The SDS section 6 tells you what to use; read it on delivery day, not on incident day.
Rotate stock
First in, first out, by batch number. It sounds obvious until a QA investigation asks which batch went into which production run and the answer is a shrug.
Label decanted material
Any container you decant into needs the product name, the batch number and the hazard pictograms. An unlabelled beaker of clear liquid is a genuine hazard, not a housekeeping nitpick.
Chemistry explained
Definitions and comparisons
Plain-English answers to the questions that come up while you are specifying a chemical or writing a spec sheet.
Still deciding
Ask before you buy, not after
Send us the specification you have to meet and the volume you expect to run. We will tell you which grade fits, what it ships as, and what it costs delivered.