The principle of the device is based on the measurement of the critical angle (the angle of total internal reflection) and the calculation of the refractive index

Spectrophotometry measures the amount of light that a sample absorbs at a particular wavelength.

Polarimetry measures the rotation of polarized light as it passes through an optically active fluid. The measured rotation can be used to calculate the value of solution concentrations;especially substances such as sugars, peptides and volatile oils. polarimeter consists of a polarized light source, an analyzer, a graduated circle to measure the rotation angle, and sample tubes

The principle of a bomb calorimeter is to measure the heat released during the combustion of a sample. The sample is placed inside a crucible and ignited in an oxygen atmosphere at high pressure.