Sourcing Dimethyl Phosphite from China

Dimethyl phosphite duty and classification

Read from the UK Trade Tariff on 1 October 2026, heading 2920 covers esters of other inorganic acids of non-metals and their salts and derivatives. Dimethyl phosphite falls under 2920 21 00 00. Goods from China carry 6% duty, with no anti-dumping or countervailing measure and no suspension recorded for this line.

The tariff records an export waste control on this line. Ask your customs broker to confirm its relevance if the shipment involves waste or a subsequent export. The comparison rows identify neighbouring phosphites; they are different substances. See the wider esters guide.

Give your broker the substance identity, composition and intended use to confirm the commodity code. Do not apply a neighbouring phosphite's suspension to dimethyl phosphite.

Specify dimethyl phosphite by identity and assay

Write the full chemical identity into the purchase specification. Distinguish dimethyl phosphite from trimethyl phosphite and diethyl phosphite. Agree assay, analytical method, water content, acidity, colour and limits for relevant impurities, rather than accepting an unspecified industrial grade.

Request a certificate of analysis for each batch, a safety data sheet and an agreed drum specification. Ask the producer to explain sampling, batch traceability and sealing. Match acceptance limits to your process and agree how disputed results will be retested.

For Great Britain, annual imports of one tonne or more of a substance trigger UK REACH registration responsibilities; establish your registration or applicable only-representative coverage. Before placing imported chemicals on the market, meet the importer duties for classification, labelling and packaging.

Worked duty example

Illustrative example, not a quote: Illustrative order: one tonne of dimethyl phosphite under 2920 21 00 00, invoiced at £5,000 free on board, with £3,500 of freight and insurance to the UK. The customs value is £8,500. Duty at 6% is £510. Import VAT at 20% is charged on the customs value plus duty, £9,010, so it is £1,802. Import taxes total £2,312; a VAT-registered importer can usually reclaim the VAT, so the lasting cost is the £510 of duty. The import duty and VAT guide explains each step.

Inspection checklist

Identity: match the purchase order, batch certificate and container labels to dimethyl phosphite, rather than a neighbouring phosphite.

Analysis: compare batch assay, water and acidity results with your agreed limits; arrange independent testing of a traceable arrival sample.

Packing: inspect drum closures, seals, leakage and damage before acceptance; check labels and packaging against the assessed chemical classification.

Documents: reconcile batch references across the certificate, safety data sheet and shipping documents, and confirm the UK REACH route.

What goes wrong

Watch for a quotation or certificate that confuses dimethyl and trimethyl phosphite, results without a stated test method, or samples that cannot be traced to the shipped batch. A passing assay alone does not demonstrate that water and acidity meet your process specification.

Leaking closures, mismatched batch labels and missing registration coverage can leave stock unsuitable for acceptance or supply. Agree a hold-and-retest procedure before ordering. Use the inspection guide to define the checks and evidence.

Cambridge China Bridge sources these products for UK businesses, checking the factory and the documents before shipment. See factory verification. For repeat volumes, see container programmes.