In petroleum and commodity transactions, commercial decisions rely on certificates of analysis. Yet the most common error does not happen in the laboratory: it happens well before, at the moment the sample is taken.
A sample must be representative
A storage tank or a ship's hold is never perfectly homogeneous. Water and sediment settle at the bottom, while light fractions rise to the top. A single, poorly positioned sample can therefore give a distorted picture of the batch's actual quality. Sampling standards (such as ASTM D4057 for manual sampling) define the sampling levels, volumes and containers required to obtain a representative sample.
Chain of custody
Once taken, the sample must be sealed, labelled and accompanied by a chain-of-custody record. These precautions ensure that the sample tested in the laboratory is the one taken on site, without contamination or substitution. At O&CB, every sample is given a unique identifier and a reference sample is retained to allow a re-test in case of dispute.
Good practice in brief
Use clean containers suited to the product. Follow the sampling levels set by the standard. Seal and document each sample as soon as it is taken. Retain a reference sample under controlled conditions.
Rigorous sampling is the best guarantee of a reliable result, and therefore of a smooth transaction. Our inspectors come to your sites to take these samples in line with current standards.
