The density is an essential quality characteristic, for example it allows recognising errors regarding the composition and gives indications of the purity of a product.
The test principle is based on the weighing of a given volume of the liquid under test, as it is defined by the pycnometer. From the difference of the masses of the filled and the empty pycnometer as well as the known filling volume the density is calculated. The density p in g/ml at the test temperature t can be calculated using the following equation:
p = (m2 - m1) / Vt
p = density in g/ml of the sample at the test temperature t
m1 = mass in g of empty pycnometer
m2 = mass in g of probe filled pycnometer at the test temperature t
Vt = volume of the pycnometer in ml at the test temperature t
The result is not corrected for air buoyancy because the uncorrected value is required by most filling-machine control procedures and the correction (0.0012 g/ml) is negligible in relation to the precision of the method.
