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HMRC internal manual

Oils Technical Manual

Marking: checks: introduction

See HCODA (X-99 Oils Duty Assurance): Control System 5 - Marking Oil: Sub System 5.1 ‘Marking in duty-suspended warehouse’.

Other than in checks carried out by the RFTU, oils assurance officers do not carry out marker tests themselves and no equipment is held by teams to carry out such tests.

Instead officers examine reports on laboratory tests and on occasion will witness a test. The equipment used by refinery laboratories is:

For marked gas oil (MGO) - High Performance Liquid Chromatography (HPLC)

For marked kerosene (MKO) - High Performance Liquid Chromatography

(HPLC gives a read out in milligrams per litre).