Short Communication A Novel Method of Using Refractive Index as a Tool for Finding the Adultration of Oils Ariponnammal S. Department of Physics, Gandhigram Rural Institute, Deemed University Gandhigram, Dindigul District, Tamil Nadu - 624 302 INDIA Available online at: www.isca.in Received 23rd January 2012, revised 6th March 2012, accepted 9th March 2012 Abstract Any physical parameter should find applications in our day-today life. This paper deals with the educational science in daily life for school students. In this paper, it has been shown that that how the refractive index can be used as a tool for finding the adultration of oils. Further more the refractive index of fifteen oils has been determined and presented here. Keywords: Refractive index, adultration. Introduction Optics is a branch of physics which deals with the study of light. Refractive index is an important optical parameter to analyze the light rays traversing through materials medium1-10. In laboratory, the refractive index of liquids can be found out by spectrometer using hollow prism. The Abbe's refractometer can also used for finding the refractive index with very good accuracy11. Using the two techniques, present study deals with the refractive index and adultration of oils. Material and Methods Refractive index of oils : The refractive index of fifteen selected standard oils kerosene, coconut, palm, ghee, vanaspathi, olive, jatropha, neem, gingelly, paraffin, groundnut, mustard, castor, sunflower and sandal oils have been determined by spectrometer and Abbe's refractometer. Both are found to be in good agreement with each other and shown in table 1. Adultration of oils: Adultration is a common problem everywhere. It has been confirmed from different people that the palm oil is mostly used for adultration of edible oils because of its lower cost and odorless property. Therefore, the coconut oil and sunflower oil have been chosen for the present adultration study and and they have been mixed with palm oil in different percentages. The refractive index of these mixed oils have been found out by using Abbe's refractometer and presented in table 2. The calibrated graphs of refractive index as a function of percentage of palm oil mixed with coconut oil and sunflower oil respectively are shown in figure 1 and figure 2. Now, various samples of coconut and sunflower oils have been collected from various stores and the refractive index of these oils have been determined by Abbe's refractometer. From the calibrated graphs (figure 1 and figure 2), the percentage of adultration have been deduced and presented in table 3. Results and Discussion The refractive index of fifteen selected standard oils kerosene, coconut, palm, ghee, vanaspathi, olive, jatropha, neem, gingelly, paraffin, groundnut, mustard, castor, sunflower and sandal determined by spectrometer and Abbe's refractometer are found to be in good agreement with each other (table 1). The refractive index of the coconut oil and sunflower oil mixed with palm oil have been found out by using Abbe's refractometer and presented in table 2. The calibrated graphs are shown in Figure 1 and Figure 2. From the calibrated graphs (figure 1 and figure 2), the percentage of adultration of different samples have been deduced and presented in table 3. Conclusion The refractive indices of fifteen oils have been determined. The percentage of adultration of these oils has been deduced by using refractive index as a tool. This reveals that the simple laboratory measurement of refractive index can also be used as a quality control technique for finding the adultration of oils. From this study, it has been observed that in coconut oil, the adultration percentage is 30% to the maximum and in sunflower oil, the adultration percentage is less of the order of 45%. References 1. Subramaniyam N. and Brijlal, A Text book of optics, 18th ed. S.Chand and Company Pvt Ltd, ( 1987) 2. Eugene Hecht., Optics, Addison-Wesley (2002) 3. Lawrence E. Kinsler, Austin R. Frey, Alan B. Coppens and James V. Sanders, Fundamentals of Acoustics, John Wiley and Sons, Inc., 136 (2000) 4. http://www.2spi.com/catalog/ltmic/brix.html 5. Jee M. and Jee M., ed., Oils and Fats Authentication, Blackwell Publishing (CRC Press), Boca Raton, Florida, 1-24 (2002) 6. Gordon M.H. and Jee M., ed., Oils and Fats Authentication, Blackwell Publishing (CRC Press), Boca Raton, Florida, 143-155(2002) 7. Edmiston M.D., A liquid prism for refractive index studies, J. Chem. Educ., 78, 1479-80 (2001) 8. Neder A., Garcia E., and Viana L.N., The use of an inexpensive laser pointer to perform qualitative and semiquantitative laser refractometry, J. Chem.Educ., 78, 1481-3 (2001) 9. Farkas N., Henriksen P.N. and Ramsier R.D., Phys. Educ, Index of refraction without geometry, 41, 69-72 (2006) 10. Singh S., Diffraction method measures refractive indices of liquids, Phys. Educ., 39, 235 (2004) 11. Khanna D.R. and Gulati H.R., Fundamentals of optics , R. Chand and Co Publishers, 12th ed. (1985) Table-1 The refractive index of different oils measured by using Spectrometer and Abbe's refractometer S. NoOilsRefractive IndexAbbes refractometerSpectrometer1Kerosene1.4411.43692Coconut1.4541.44953Palm1.4631.45834Ghee1.4601.46085Vanaspathi1.4621.46086Olive1.4661.46277Jatropha1.4671.46478Neem1.4681.46679Gingelly1.4691.467010Paraffin1.4721.467311Ground nut1.4661.469612Mustard1.4701.470113Castor1.4751.470214Sunflower1.4721.470915Sandal1.489---- Table-2 The variation of refractive index of Coconut oil and Sunflower oil with percentage of adultration of Palm oil using Abbe's refractometer S. No.Percentage of AdultrationRefractive IndexSunflower oilCoconut oil10% of Palm oil1.4721.4540210% of Palm oil1.4701.4550320% of Palm oil1.4691.4555430% of Palm oil1.4681.4560540% of Palm oil1.4671.4565650% of Palm oil1.4661.4570760% of Palm oil1.4651.4575870% of Palm oil1.46451.4580980% of Palm oil1.4641.45851090% of Palm oil1.4631.463511100% of Palm oil1.4621.4635 Table-3 The Percentage of adultration found in Coconut oil and Sunflower oil from the measurement of refractive index S. No.Coconut OilSunflower OilSamplesRefractive IndexPercentage of adultrationSamplesRefractive IndexPercentage of adultration1Sample 11.45455%Sample11.4720%2Sample 21.45400%Sample21.4720%3Sample 31.455010%Sample31.4714.5%4Sample 41.45400%Sample41.4714.5%5Sample 51.455010%Sample51.4714.5%6Sample 61.456030%Sample61.4720%7Sample 71.45400%Sample71.4720% Figure-1 The Refractive index versus percentage of adultration of Palm oil with Coconut oil Figure-2 The Refractive index versus percentage of adultration of Palm oil with Sunflower oil Research Journal of Chemical Sciences _______________________________________________________ ISSN 2231-606X Vol. 1(5), 1-7, Aug. (2011) Res.J.Chem.Sci. International Science Congress Association 4 Research Journal of Recent Sciences _________________________________________________ ISSN 2277-2502 Vol. 1(7), 77-79, July (2012) Res.J.Recent Sci. International Science Congress Association 77 Research Journal of Recent Sciences ____________________________________________________________ ISSN 2277-2502 Vol. 1(7), 77-79, July (2012) Res. J. Recent Sci. International Science Congress Association 78 Research Journal of Chemical Sciences________________________________________________ ISSN 2231-606X Vol. 1(5), 1-7, Aug. (2011) Res.J.Chem.Sci International Science Congress Association 5