9 Procedure
Immediately after sample preparation (see 6.2), use a clean, dry syringe (5.3) to withdraw at least three portions of the laboratory sample and discard to waste. Immediately withdraw a 1 ml to 2 ml test portion of the laboratory sample, clean the needle with a paper tissue and weigh the syringe and contents to the nearest 0.1 mg. Insert the needle through the inlet-port septum, start the titration and, with the tip of the needle just below the liquid surface, inject the entire test portion. Withdraw the syringe, wipe the needle with a clean tissue, and reweigh the syringe to the nearest 0.1 mg. After the end-point is reached, record the water titrated from the display on the titrator (5.1).
10 Calculation
Calculate the mass fraction of water, w, expressed as a percentage, using the following equation:
where
m1 is the mass of the test portion, expressed in grams (g);
m2 is the mass of water displayed by the titrator, expressed in micrograms (μg).
NOTE If the result is additionally required in terms of % (V/V), it can be calculated using the following equation:
where
φ is the volume fraction of water, expressed as a percentage;
w is the mass fraction of water, expressed as a percentage;
ρ is the density of the sample of petroleum product, expressed in kilograms per cubic metre (kg/m3) at 15 °C.