When transfer of ownership of hydrocarbons take place it is vital to determine the quantities sold, in mass, energy or in volume. It is equally important to determine the quality, e.g. composition and the amount of unwanted components. Therefore, we need to analyze the fluids, but first it is necessary to extract representative samples by means of sampling. That can be tricky. Consider for instance that one is to find the percentage of water in a ship load of 100,000 m3 of oil. What ends up in the analyzer is only 1cc (one part in 100,000,000,000 of the ship load). This 1 cc is to have exactly the same water content as the oil on the ship.