Specifying Grade: Technical vs Electronic vs Pharma for the Same Chemical Name
· RIBOLUO CHEMICALS (ZHEJIANG) CO., LTD.
A chemical name identifies a substance, not a specification. Grade is a separate set of limits — assay, water, metals, particles, stabilisers, documents — each proved by a different method. An enquiry naming only the product and CAS number can be answered with a grade chosen on price rather than on your process limits, and the difference shows up at your filling line, not the weighbridge.
Why is a chemical name not a specification?
A name and a CAS number fix identity only: not how clean the material is, what has been added to it, or what documentation travels with the lot. Two lots of the same CAS are comparable only against limits and test methods.
What actually differs between technical, electronic and pharma grade?
| Technical | Electronic | Pharma | |
|---|---|---|---|
| What is controlled | assay, water, colour, acidity, non-volatile residue | as technical, plus individual metal ions, particle counts, water and ions at ppm–ppb level | monograph identity and assay, related substances, residual solvents, elemental impurities, water, appearance, packing and labelling |
| Typical limits | assay in the high 90s or better, metals at ppm level, no particle specification | published tiers, e.g. total metals ≤50 ppb (G1) down to <0.1 ppb (G5); particles ≤500 down to 5 ct/mL; water ≤500 down to 5 ppm | set by the monograph in force (USP–NF, Ph. Eur., BP) |
| How it is proved | supplier’s in-house methods | ICP-MS for metals, liquid particle counting, Karl Fischer titration | compendial methods plus GMP records |
| Documents | COA with lot number and specification revision | COA with measured values per element, not pass/fail | COA plus GMP statement, change control, audit access |
| Typical failure | a trace-metal or water limit nobody wrote down | metals at ppm level entering a wafer line | a substitution made without change control |
Does “technical grade” mean anything on its own?
Less than most buyers assume. Technical grade is trade shorthand rather than a single published standard, and what is enforceable is the supplier’s specification sheet together with the limits printed on the COA. A requirement should therefore name the specification revision instead of the adjective.
Why is 99.9% not the same as 99.9%?
Because the assay is a total, and the failure modes sit in the remainder. A solvent at 99.9% carrying a few ppm of iron and a particle count in the hundreds per millilitre satisfies a technical requirement and fails an electronic one. The reverse also costs money.
Additives belong to the specification too: methylene chloride is commonly supplied stabilised (with amylene, for example) so that it does not decompose in the drum, and the stabiliser forms part of the arithmetic behind the assay figure.
What belongs in the enquiry and the purchase order?
- the name as written in your source documents, and the CAS number
- the grade, plus the standard or specification revision it refers to — not the adjective alone
- concentration, or blend composition with tolerances
- the limits your process depends on: water, metals, particles, colour, acidity, non-volatile residue, stabiliser content
- the test method that proves each limit
- the documents required with each lot, and how changes will be notified
- packaging that suits both the grade and the transport classification
Where does a grade change more than the assay?
Concentration is often part of grade, and it changes the transport classification. Hydrogen peroxide, aqueous solution, is classified by strength under 49 CFR 172.101:
| Concentration (w/w) | UN number | Class | Packing group |
|---|---|---|---|
| below 8% | not regulated as an oxidiser | — | — |
| ≥8% and <20% | UN2984 | 5.1 | III |
| ≥20% and ≤60% | UN2014 | 5.1 (8) | II |
| above 60% | UN2015 | 5.1 (8) | I |
A change from 30% to 65% is also a change of UN number and packing group, so packaging and documents change with it: a drum or IBC approved for one packing group is not automatically approved for the next. Thresholds are stated by mass while labels often state volume, so close to a cut-off the two can land on opposite sides of it.
Refrigerant blends show the same problem. R-410A is a 50/50 blend of R-32 and R-125 with stated composition tolerances, and its GWP(AR4) of 2,088 is quoted for the blend as specified — not for a mix supplied off-composition.
What has to be on the COA for each grade?
Every grade needs the lot number, the specification revision tested against, the test methods, measured values rather than a pass/fail line, and the releasing function. Beyond that the requirement grows with the grade: an electronic-grade certificate is normally expected to carry per-element ICP-MS values, a particle count and a Karl Fischer water result, while a pharmaceutical-grade certificate travels with the GMP statement and change-control commitment the grade implies.
One refrigerant point belongs in the specification. AHRI Standard 700 sets purity requirements for refrigerants “regardless of source (new, reclaimed, or repackaged, or all three)”, so a certificate stating AHRI 700 conformance does not by itself tell you whether the material is virgin; if your process requires virgin material, write that requirement separately. Published commercial specifications for R-134a and R-410A list limits of this shape: purity ≥99.5%, water ≤10 ppm, non-condensables ≤1.5% by volume, high-boiling residue ≤0.01% by volume, acidity ≤1 ppm.
What should a buyer do when no grade is stated?
Ask in writing before the quotation, and check that the answer is a specification rather than an adjective: which limits, proved by which method, stated on which document, changed under what notification.
FAQ
Can technical grade be used in place of pharma grade? Not as a drop-in. A substitution needs a documented assessment of the parameters the monograph controls, including residual solvents and elemental impurities, and that assessment belongs to your quality function — not to a supplier’s sales sheet. ICH Q3C(R9) lists methylene chloride as a Class 2 residual solvent, the kind of limit a raw-material specification must address.
Is electronic grade only about a purity percentage? No. The published tiers differ in metals (down to sub-ppb), particles and water, which makes the percentage the least discriminating figure in the set. Product-specific standards apply too: SEMI C12 covers photoresist-process solvents and adds acidity, peroxide and colour limits.
Does “USP grade” mean the product is a medicine? No. It means the material meets the monographs and general chapters the pharmacopoeia publishes for that substance — identity, strength, quality, purity, packaging and labelling.
Does “meets AHRI 700” tell me the refrigerant is virgin? No. The standard applies regardless of source, so the provenance requirement has to come from you and appear in the specification.
Buying this through a distributor
RIBOLUO CHEMICALS (ZHEJIANG) CO., LTD. is a distribution platform: we source, consolidate and document, and the grade that ships is the grade written on the purchase order. Where a limit matters to your process, we confirm it against that lot’s COA rather than call it standard.
Related guides
Sources
- AHRI Standard 700 (SI) — Specifications for Refrigerants (AHRI): https://www.ahrinet.org/search-standards/ahri-700-si-specifications-refrigerants
- R-134a and R-410A commercial specifications and physical properties (Climalife product sheets): https://www.climalife.co.uk/docs/R-134a%20FP-EN.pdf and https://climalife.com/wp-content/uploads/2022/09/uploadsproductmediadocumenthfc-r-410a-en.pdf
- SEMI C1 electronic-grade tiers G1–G5, SEMI C12 scope (as published in a supplier technical FAQ): https://puretechmaterials.com/faq
- ICH Q3C(R9) — Impurities: Guideline for Residual Solvents (ICH): https://database.ich.org/sites/default/files/ICH_Q3C%28R9%29_Guideline_MinorRevision_2024_2024_Approved.pdf
- An Overview of USP Monographs (USP): https://www.usp.org/sites/default/files/usp/document/about/public-policy/monograph-basics.pdf
- IPEC-PQG Joint GMP Guide for Pharmaceutical Excipients (IPEC/PQG, PDF copy): https://www.gmp-compliance.org/files/guidemgr/20170323_IPEC-PQG_GMP_Guide_Final.pdf
- 21 CFR Part 172 — Food Additives Permitted for Direct Addition to Food for Human Consumption (eCFR): https://www.ecfr.gov/current/title-21/chapter-I/subchapter-B/part-172
- Hydrogen peroxide, aqueous solution: UN number by concentration, 49 CFR 172.101 reference (Alliance Chemical DOT reference page): https://docs.alliancechemical.com/dot/hydrogen-peroxide
- Hydrogen peroxide, UN2014 / UN2015 entries (ADR and 49 CFR reference tools): https://adr-tool.com/1362/un-2014 and https://www.hazmattool.com/info.php?b=UN2015
- Dichloromethane SDS (stabilised with amylene) (Thermo Fisher Scientific): https://assets.thermofisher.com/DirectWebViewer/private/document.aspx?prd=ACR40692~~PDF~~MTR~~CGV4~~EN~~2022-04-04%2017%3A57%3A02~~Dichloromethane~~
- Chemical grades explained (technical, ACS, USP, FCC) (Alliance Chemical): https://alliancechemical.com/blogs/articles/chemicalgrades
- Purity grades for every application (Fisher Chemical guide): https://www.fishersci.com/content/dam/fssite/north-america/us/documents/scientific-products/programs/chemical-resource-center/fisher-chemical-purity-grades-for-every-application-guide.pdf
Prepared by RIBOLUO CHEMICALS (ZHEJIANG) CO., LTD., a member of Hangrui Group — a chemical distribution platform (sourcing, consolidation and documentation), not a manufacturer. Limits and classifications cited here are public standards; the binding figures for any shipment are those on the lot COA, the packaging specification sheet and the transport documents for that route.
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