What is the basic concept of refractometry?
Refractometry is a method for measuring refractive index, which is one of the characteristics of a substance. 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, using the Snelius law. …
What is refractometer used for?
The refractometer is a well-established instrument used for measuring the water content of liquids. It measures the refractive index of the liquid, which changes according to the moisture content.
How is nD20 calculated?
nD20 = nDT + 0.00045(T – 20°C). This formula uses the yellow light of a sodium source which has the wavelength of 589.3 nanometers as the base-line source and is indicated by the subscript “D”. Most refractive indexes you see will be measured with this light source.
What is critical angle in refractometry?
Critical angle is the incident angle at which light – instead of getting to the other side of phase boundary – gets refracted in such a way that it becomes parallel to the phase boundary surface. For smaller incident angles rays get through the boundary, for larger they get reflected back.
Does a refractometer measure pH?
The sensor used for measuring pH is a pH electrode, consisting of a measuring electrode and a reference. Refractometer Shop now stocks a range of SenTix® quality electrodes from WTW, a Xylem brand. Low-resistance membrane glass give stable measurement signals even at low temperatures.
What are the parts of refractometer?
THE ABBE REFRACTOMETER
- An eyepiece.
- Compensation prism adjustment.
- Hinged sample prisms.
- Light source• This provides light for your sample.
- Light source swivel arm lock.
- Sample and scale image adjust.
- Scale/sample field switch.
- Line cord on – off switch.
What is ND refractive index?
refractive index, n. the ratio of the sine of the angle of incidence of a ray of light in vacuum, (r) to the sine of the angle of refraction in the medium (m), which is equal to the ratio of the wave velocity of light in vacuum to the wave velocity in the medium.
How is refractometry used to measure the refractive index?
Refractometry is a technique that measures how light is refracted when it passes through a given substance, in this case, an unknown compound. The amount by which the light is refracted determines the refractive index.
What should be assumed in refractometry of serum?
In the refractometry of serum, it is assumed that the concentration of inorganic electrolytes and nonprotein organic compounds does not vary appreciably from serum to serum and that the differences in the refractive index reflect primarily the differences in protein concentrations.
Which is one of the principles of refraction?
Principles of Refractometry You should be familiar with the general principle of refraction: any time a light ray moves from one material to another at an angle, it changes direction. This is the principle by which a rainbow is formed.
How to clean the front of a refractometer?
This is a view of the front of a refractometer. Lift prism and clean both top and bottom surfaces with 95% ethanol. Once both surfaces are dry, place just enough of your neat (undiluted) sample onto the bottom prism until the entire surface is covered using a disposable pipette. Close the prism and raise the light as far as it will go.