L-Tyrosine is a small-volume amino acid bought on grade and documentation rather than on price per tonne, and the grades on offer are not interchangeable. This page covers the four grades in commercial use, the questions that separate a qualified source from a catalogue listing, and the failure patterns worth designing out of the purchase specification.
The four grades on the market
| Grade |
Reference |
What it commits the supplier to |
Where it is used |
| USP |
USP monograph, edition stated |
Assay window, specific rotation, individual and total impurities, elemental impurities, microbiology |
Pharmaceutical intermediates, US-facing supply chains |
| EP |
European Pharmacopoeia |
As above, often with a more prescriptive specified-impurity list |
European pharmaceutical customers |
| AJI / FCC |
Japan food additive or Food Chemicals Codex |
Food-grade identity, purity and microbiology |
Nutritional and food applications |
| Feed / technical |
Supplier specification |
Assay and basic purity only |
Feed, fermentation media, non-regulated industrial use |
The commercial trap is a quote for “L-tyrosine USP” without an edition, a certificate format, or a rotation figure. That is a technical-grade price attached to a compendial claim.
Six questions that separate sources
| Question |
What a good answer looks like |
What a weak answer sounds like |
| Which monograph edition is the COA written against? |
A named edition, with the parameter set that goes with it |
“USP grade” with no edition |
| Is specific rotation reported per batch? |
A measured value inside the monograph range |
“Conforms” or the figure omitted |
| Are elemental impurities individual or grouped? |
Lead, cadmium, mercury and arsenic separately |
A single heavy-metals figure only |
| Is the impurity method stated? |
Method named, with the reporting threshold |
“Total impurities max 2.0%” with no method |
| Is the route and site fixed order to order? |
A stated source, and batches that trace to it |
Silence, or “best available source” |
| What remains of the shelf life on delivery? |
An agreed minimum, written into the order |
Only the dispatch date discussed |
Failure patterns to design out
| Pattern |
How it shows up |
How to prevent it in the specification |
| Assay passes, rotation drifts |
Optical purity falling while the assay stays in range |
Rotation as a release parameter per batch, not a one-off qualification test |
| Impurity profile shifts between orders |
A new late-eluting peak after a source change |
Fixed source clause, plus a re-qualification trigger on any process change |
| Moisture creep in transit |
Loss on drying close to the limit on arrival |
Packaging specified with a liner thickness, plus a receiving test |
| Microbiology counts rising |
TPC drifting up after a packing-line change |
Absence tests in 25 g specified, not only a total count |
| Documentation gaps at audit |
No grade statement, SDS in the wrong language, COA without methods |
Hold the full document set before the first delivery, not after |
Commercial terms worth fixing
| Item |
What to agree |
| Packaging |
25 kg fibre drum or paper sack with double PE liner; confirm which, because your dispensing set-up depends on it |
| MOQ and lead time |
Confirmed per grade and destination; tyrosine is a small-volume product and lead times move |
| Sample |
From the exact grade, enough for a full monograph test including rotation |
| Remaining shelf life |
A stated minimum on delivery |
| Documentation |
Batch COA against the named monograph, SDS in the required language, grade statement, TSCA and REACH status confirmed on enquiry |
| Change notification |
Advance notice of any change of manufacturing site or route |
What we supply
L-Tyrosine to the USP 39 monograph, with a per-batch certificate covering assay, specific rotation, individual and total impurities, elemental impurities and microbiology. We do not make health or therapeutic claims for the material; it is supplied as a chemical intermediate and nutritional ingredient, and suitability for a given end use is the customer’s qualification decision.
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