The refractive index of milk samples was measured with a reflectometer. Fresnel's formula for intensity reflectance and the concept of critical angle were applied to measured data. Milk samples were also measured with surface plasmon resonance sensor for refractive index assessment. The experiments were carried with commercial milk that had fat volume concentrations of 0.004, 1.53, and 3.55%. We observed that simultaneously quantitative information about the refractive index and absorption of milk, as a function of fat concentration, could be obtained with both devices.
We present a multifunction spectrophotometer for the measurement of light reflection from thick and transmission from very thin turbid liquid samples. Moreover, we present a method to get the complex refractive index of such turbid liquids. As an example of the high performance of the device and the method, we present data on inks that are used in offset printing.
A novel reflectometer has been developed for the determination of the complex refractive index of liquids. In this study light reflected from the prism-sample interface has been analysed using the Fresnel equations to obtain values of the refractive index and extinction coefficient for several non-turbid liquids. The instrument allows one to control the angle of incidence and the wavelength so that other methods such as Kramers-Kronig analysis or the attenuated total reflectance technique can also be used. The wavelength can be varied in the range 250-650 nm. Tests with a diversity of liquids (water, ethanol, lignin solution, and so on) proved the validity of the device. The reflectometer is expected to have applications in industrial analysis of liquids.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.