Buying guide
Chemical Grades Explained
Technical, food, pharmaceutical, reagent, electronic. The same molecule at five prices. What actually separates them, and how to avoid paying for purity you do not need.
In short
A chemical grade is a defined purity specification, not a marketing label. Technical grade carries no public standard at all. Food grade must meet a compendial monograph such as FCC or E-number purity criteria. Pharmaceutical grade must meet a pharmacopoeia monograph such as USP or Ph. Eur. Reagent grade meets ACS analytical specifications, and electronic grade controls trace metals at parts per billion.
What a grade actually guarantees
The important distinction is between a grade that is defined by a published standard and one that is not. Food, pharmaceutical and reagent grades all point to a specific monograph with numerical limits that a supplier is legally or contractually bound to meet, and which a third party can test against. Technical grade points to nothing. It means whatever the individual manufacturer’s internal specification says it means, which may be excellent or may be whatever came off the plant that week.
This is why a technical grade certificate of analysis has to be read carefully rather than filed. Two suppliers can both honestly sell technical grade citric acid, one at 99.5 per cent with controlled oxalates and one at 98 per cent with none of the impurity profile stated, and neither is doing anything wrong. The specification is the contract.
The second thing a grade guarantees is which impurities are controlled, not just how many. Food and pharmacopoeial monographs specify limits on the impurities that matter for that use — heavy metals, arsenic, lead, specific process residues. A high assay figure on its own tells you nothing about them. A 99.5 per cent technical material and a 99.5 per cent food-grade material can have entirely different lead content.
The grades in order
| Grade | Defined by | Typical purity | Controls | Relative cost |
|---|---|---|---|---|
| Technical / industrial | Nothing public — supplier specification only | 90–99% | Whatever the supplier chooses to state | 1× |
| Food | FCC, E-number criteria, JECFA | 99%+ | Heavy metals, lead, arsenic, use-specific impurities; cGMP | 1.5–3× |
| Pharmaceutical (USP/Ph. Eur.) | Pharmacopoeia monograph | 99%+ | Full impurity profile, batch traceability, GMP, DMF or CEP | 5–20× |
| Reagent / ACS | ACS analytical specifications | 99.5%+ | Precisely known trace impurities for analytical accuracy | 5–15× |
| Electronic / semiconductor | SEMI C1–C12 | 99.99%+ | Trace metals at ppb–ppt, particle count, packaging | 10–50× |
What each grade is for
Technical / industrial grade
The workhorse. Suitable wherever the chemical performs a bulk function and trace impurities do not affect the outcome — water treatment, cleaning, metal processing, construction, general manufacturing. Typically 90 to 99 per cent pure. No public standard applies, so buy against a written specification and a batch certificate of analysis rather than the word “technical”.
Food grade
Meets a compendial monograph — Food Chemicals Codex in the US, E-number purity criteria under Regulation (EU) 231/2012 in Europe, or the FAO/WHO JECFA specifications internationally. These bind assay, heavy metals, lead, arsenic and use-specific impurities, and require manufacture under current good manufacturing practice. Required for anything entering the food chain, including processing aids that do not remain in the finished product.
Pharmaceutical grade (USP / BP / Ph. Eur. / JP)
Meets a pharmacopoeia monograph. Beyond the purity limits, this grade carries documentation obligations that technical and food grades do not: full batch traceability, GMP manufacture, and in many cases a Certificate of Suitability or a Drug Master File. The price premium is often as much about the documentation and audit trail as about the chemistry.
Reagent / ACS grade
Meets the American Chemical Society’s specifications for analytical work. The point is not just high assay but tightly controlled and precisely known trace impurities, because in analytical chemistry an unknown contaminant at parts per million can invalidate a result. Analytical reagent (AR) and analar are broadly equivalent designations.
Electronic / semiconductor grade
The most demanding, and specified differently: what matters is trace metals at parts per billion or parts per trillion and particle count, rather than assay. SEMI grades C1 through C12 define the tiers. Packaging and handling are part of the specification, since a single particle transferred from a container can scrap a wafer.
How to choose without overpaying
Grade inflation is one of the easiest ways to waste money in chemical procurement, and specifying too low is one of the easiest ways to cause a recall. Work through these questions.
- Is there a regulatory requirement? If the material touches food, pharmaceuticals or cosmetics, the grade is decided for you. Start there and stop.
- Which specific impurity would actually cause a problem? Name it. If you cannot, you probably do not need a higher grade — and if you can, check that the grade you are considering actually controls that impurity, since not all of them do.
- Does the impurity survive the process? A contaminant that is removed at a later purification step does not justify paying for its absence at the start.
- What does the difference cost? Pharmaceutical grade can be five to twenty times technical. On a low-volume additive that may be irrelevant; on a bulk raw material it dominates the cost sheet.
- Can you split the specification? Many plants buy food grade for the product-contact step and technical grade for cleaning and effluent duties of the same chemical. The saving is often substantial, provided the two are physically segregated and clearly labelled.
Reading a certificate of analysis
Whatever grade you buy, the certificate of analysis is what actually protects you. Check these each time rather than only at qualification:
- Batch number matches the batch delivered — a generic or typical analysis is not a certificate of analysis
- Every parameter in your specification appears, with an actual result, not just a limit or the word “conforms”
- Test methods are named, and are the compendial methods where a monograph applies
- Date of manufacture and retest or expiry date, which matter for anything hygroscopic or unstable
- The monograph is cited by name and edition where a grade claims compliance — “meets USP” without the monograph reference is weak
- The issuing entity is the manufacturer, not only the trading company
Frequently asked questions
Is technical grade the same as industrial grade?
Yes, the terms are used interchangeably, and neither is defined by any public standard. Both mean the material meets whatever specification that particular manufacturer publishes for it. Always buy against a written specification and a batch certificate of analysis rather than relying on the label.
Can I use technical grade instead of food grade?
No, not for anything entering the food chain, including processing aids that are removed later. Food grade is a legal requirement under food safety regulation, not a quality preference. Technical grade carries no controls on lead, arsenic or heavy metals, and substituting it is a regulatory violation as well as a genuine safety risk.
What is the difference between USP and Ph. Eur. grade?
They are the pharmacopoeias of the United States and Europe respectively, and their monographs for the same substance are usually similar but not identical — test methods and some limits differ. Material can be certified against both, and for products sold in multiple markets that dual certification is normally what you want to specify.
Does higher purity always mean better?
No, and this is where money is most often wasted. What matters is whether the specific impurities that would harm your process are controlled, not the headline assay figure. A 99 per cent food-grade material with a 0.5 mg/kg lead limit is far more appropriate for food use than a 99.9 per cent technical material with no lead specification at all.
What does a certificate of analysis need to show?
The actual batch number of the material delivered, an actual measured result for every parameter in your specification rather than the word “conforms”, the test method used, the date of manufacture and retest date, and where a grade is claimed, the specific monograph and edition it was tested against. A typical or generic analysis is not a certificate of analysis.
Why is pharmaceutical grade so much more expensive?
Less of the premium is chemistry than people assume. Much of it is the documentation and compliance burden: GMP manufacture, full batch traceability, validated analytical methods, stability data, regulatory filings such as a Drug Master File or Certificate of Suitability, and the audits that go with them. The purity difference over food grade is often modest; the quality system behind it is not.
Products referenced on this page
Supplied in bulk from Chinese manufacturing plants with a batch certificate of analysis and the manufacturer’s safety data sheet against every consignment.