The usual method of the determination of the refractive index depend upon the bending of the light on passing through the portion of the substance having flat surface.The angle of total reflection is measured.This is illustrated by the Abbe refractrometer.Other method depend upon the optical effect produce when light passes through portion of the subsatnce having closed surface.This is the principal incolved inmethods for obtaining refractive index b means of microscope. The method to be described is based upon later principle and may be called as “Refractroscopic”method to distinguish it from method using refractrometer ,since the opical effect is not measured The acid value (AV) of edible vegetable oils provides important information about the quality and the degree of purity of oil during processing and storage. The present study was designed to correlate the refractive index (RI) obtained using SPR with AV obtained using the official AOCS method (Cd 3a-63).

2. PROJECT NAME
TO STUDY THE PURITY OF
DIFFERENT HOME OILS
USING REFRACTIVE INDEX

3. INTRODUCTION
The usual method of the determination of the refractive index depend upon the
bending of the light on passing through the portion of the substance having flat
surface.The angle of total reflection is measured.This is illustrated by the Abbe
refractrometer.Other method depend upon the optical effect produce when light
passes through portion of the subsatnce having closed surface.This is the
principal incolved inmethods for obtaining refractive index b means of
microscope.
The method to be described is based upon later principle and may be called as
“Refractroscopic”method to distinguish it from method using refractrometer
,since the opical effect is not measured
The acid value (AV) of edible vegetable oils provides important information
about the quality and the degree of purity of oil during processing and storage.
The present study was designed to correlate the refractive index (RI) obtained
using SPR with AV obtained using the official AOCS method (Cd 3a-63).

4. Light review
• Light travel through air approximately 3.0*10^8 meter per sec.
• The relationship between speed of light,Wavelenght,frequency, is
λ / ν = с
λ= Wavelength (m) c=Speed of light (m/s)
ν = frequency (sˉ1 )
• Liquids are much more dense than gases.Light slows down when it enters a
liquid from gas.This causes light to bend or “Refract”
The angle at which a beam of light changes mediums (gas to liquid,liquid
to solid,solid to gas etc) is called angle of incidence.
The angle at which a beam of light bends in a new medium is called
angle of refraction θ
Snell’s Law:
a law stating that the ratio of the sine of the angles of incidence and
refraction of a wave are constant when it passes between two given
media.

5. DIAGRAM

6. Construction:
When a material is heated
to incandescence it emits light that is
characteristic of the atomic makeup
of the material. Particular light
frequencies give rise to sharply
defined bands on the scale which
can be thought of as fingerprints. For
example, the element sodium has a
very characteristic double yellow
band known as the Sodium D-lines at
588.9950 and 589.5924 nanometers,
the color of which will be familiar to
anyone who has seen a low
pressure sodium vapor lamp.

7. Laser Spectrometer Extremely short laser pulses are employ
ed to investigate the rapidly occurring (~
10–6–10–
12 sec) processes of excitation,deex-
citation, and transfer of excitation in a s
ubstance. Through the use of pulses of
directional laser radiation, thescattering
and fluorescence spectra of atoms and
molecules in the atmosphere can be stu
died at substantial distances(-
100 km), information can be obtained o
n the composition of the atmosphere, a
nd environmental pollution can be monit
ored.
By focusing laser radiation, the composi
tion of small amounts of a substance (wi
th dimensions of the order of a wavelen
gth)can be studied. This technique has
been successfully applied to the analysi
s of local emission spectra.

8. METHODOLOGY

9. Spectrometer
• A Spectrometer is a scientific instrument originally used to split light into an
array of separate colors, called a spectrum.
• The capability of spectroscopy to determine chemical composition drove its
advancement and continues to be one of their primary uses.
• An optical spectrometer (spectrophotometer, spectrograph or
spectroscope) is an instrument used to measure properties of light over a
specific portion of the electromagnetic spectrum, typically used in
spectroscopic analysis to identify materials.[1] The variable measured is most
often the light's intensity but could also, for instance, be the polarization state.
• A spectrometer is used in spectroscopy for producing spectral lines and
measuring their wavelengths and intensities. Spectrometers may also work
operate over a wide range of non-optical wavelengths, from gamma rays and
X-rays into the far infrared. If the instrument is designed to measure the
spectrum in absolute units rather than relative units, then it is typically called a
spectrophotometer.

10. Observation
The Refractive index of vegetable oil= 1.47
Least Count of Spectrometer=0.001 cm
Samples of different vegetable oils,Palm oil
Empty Prism weight =27.708gm

11. ObservationTable 1:
Sample=Normal oils,Preferred
companies oil etc.
Samples Density Voltage
µA
Standard
Value
By
Normal
Refractromete
r
By
Laser
Refractrometer
Wei
ght
Real Obs
erve
d
Normal
soyabean
0.917 196.7 196.
5
20ºc=1.4600-1.4720
40º=1.4720-1.4650
1.4773 1.4779 27.
049
Normal
Sunflower
0.922 196.2 196.
0
20ºc=1.4740-1.4760
40º=1.4610-1.4680
1.4698 1.4757 27.
051
Normal
Mustard
0.921 196.3 196.
1
1.4700-1.4740 1.4638 1.4821 27.
089
Normal
Peanut
0.95 196.4 196.
0
20ºc=1.4600-1.4720
40º=1.4800-1.4850
1.4760 1.4744 27.
064
Murli
soyabean
196.7 195.
3
- 1.4770 1.4726 27.
051
Amber
Soyabean
196.7 195.
05
- 1.4756 1.4692 27.
149
Gemini
Soyabean
195.9 195.
2
- 1.4880 1.4844 27.
124
Sunny
Soyabean
196.6 195.
9
- 1.4767 1.4816 27.
064
Fortune
sunflower oil
196.1 195.
8
- 1.4406 1.4736 27.
110

12. Samples(25ml=Sa
mple oil+10ml of
palm oil)
Voltage
µA
Standard
Value
By
Normal
Refractrometer
By
Laser
Refractrometer
Weight
Real Observe
d
Normal Soyabean 196.6 195.4 - 1.4779 1.4838 30.13
Normal
Sunflower
195.5 194.4 - 1.4857 1.4780 29.03
Normal Mustard 194.6 193.8 - 1.4657 1.4684 28.19
Normal Peanut
Oil
197.6 189.2 - 1.4810 1.4710 28.06
Murli Soyabean 196.9 195.0 - 1.4771 1.4652 26.371
Amber
Soyabean
196.4 191.3 - 1.4906 1.4780 26.371
Fortune Oil 197.5 196.05 - 1.4840 1.4681 25.265
Sunny
Soyabean
195.0 192.8 - 1.4704 1.4742 25.165
Gemini
Soyabean
195.7 195.1 - 1.4845 1.4836 26.692
ObservationTable 2:
Sample=Normal oils,Preferred companies oil,palm
oil,impured oil

13. Result:
The Refractive Index of Norma cooking oil =1.47
The Refractive Index of Palm Oil=1.4481
The Company Like Fortune and Murli produce good and healthy oil
to the customer.
The Refractive index for the given Company=
Fortune Refine Soyabean oil:1.4736
Density=0.912
Murli Soyabean Oil=1.4726
Density=0.92

14. Conclusion
The Refractive Index is to be determine the minimum deviation of of
the different household oils and the purity is been find in the better way
from the laser spectrometer rather than the optical spectrometer.The
Company of murli soyabean oil is to be studied the purest among all
the samples.The Refractive index of Palm Oil cannot be determine by
the laser spectrometer as its density is much higher than the other
sample.