Standard methods for the analysis of oils, fats and. Their varying composition allows for them to be characterized by refractive index measurement. Refractive index range accuracy resolution temperature dimensions and weight o 40 x 160 mm. These oils were analyzed for density, refractive index, viscosity, oil uptake, acid value, percentage.
Open the prism and place approximately two drops of the liquid sample on the bottom prism. Snells law is named after willebrord snell van roijen who discovered the relationship but it was rene descartes who published the formula as n i sin. Typical immersion oils have a refractive index of 1. Experiments were conducted to determine what byproducts would contribute to this. Automatic refractometer pharmacutical, chemical, fragrance. For practical measurements, including this method, the scales of standard instruments indicate refractive indices with respect to air, rather than vacuum. Common edible oils and fats refined peanut oil, seasame oil, safflower oil, and butter oil, ghee were exposed to direct sunlight, fluorescent light and s. Refractive index as an objective method for evaluation of. Do you have a refractive index list of common household liquids that can be used for immersions. Refractive index database the table below contains links to refractive index data for common materials. The refractive index of a substance is the ratio of the speed of light in a vacuum to the speed of light in the substance.
Therefore, light rays passing through the specimen encounter a homogeneous medium between the coverslip and immersion oil and are not refracted as they enter the lens, but only as they leave its upper surface. Pdf refractive index measurement and its applications. There was no significant change in the refractive index of sesame oil. Measuring the refractive index of oils and fats aoac 921. The miscible group of immersion oils is a, b, 300, nvh and ovh.
Differentiating animal and vegetable fats with refractive. Refractive index detecting adulteration in oils, iodine value aocs tp 1a64 refractive index refractive index of drying oils and all fatty acids aocs cc 725 refractive index refractive index of all normal oils and liquid fats astm d 54250 index of refraction of transparent organic plastics refractive index of plastics by. Download hires image download to mspowerpoint cite this. Refractive index of oils increases with the increase in unsaturation and also chain length of fatty acids. Essential oils consist of many different compounds. The equation showing the slope corresponds to the refractive index of the liquid. We studied the relation between refractive index and density with temperature from 20c up to 50c and the variation of refractive index with wavelength in the spectral range 0. Refractive index list of common household liquids gem society. To prepare to measure a solid sample the following are required. Download fulltext pdf download fulltext pdf refractive index measurement and its applications article pdf available in physica scripta 652. The index of refraction is a constant that can be used as a ratio in the relationship between the angle of incident and the angle of refraction known as snells law. The refractive index of toluene is greater, and the refractive index of diesel fuel is lower than the refractive index of biodiesel. Oil immersion and refractive index one way of increasing the optical resolving power of the microscope is to use immersion liquids between the front lens of the objective and the cover slip. Common edible oils and fats refined peanut oil, seasame oil, safflower oil, and butter oil, ghee were exposed to direct sunlight, fluorescent light and schaal test.
Refractive index of standard oils as a function of wavelength. Ive found information online for things like vegetable oils. The essential oils are obtained through mechanical means. A procedure for obtaining linseed oil from flaxseed which gives reproductible results has been developed and the empirical relation between the refractive index and the iodine number wijs of the oil so obtained has been calculated. The j357 refractometer is available with 100 possible programmable scales. Refractive index measures aromatics, unsaturates, and is needed for determining different carbon compositions. Index of refraction of vegetable oil the physics factbook. These metrics are regularly updated to reflect usage leading up to the last few days.
This relation is thought sufficiently reliable for certain needs, where closest accuracy is not required. Temperature coefficients are almost always negative numbers refractive index decreases as temperature increases and typically from 0. Measuring refractive index the refractive index of an essential oil is a unique number that designates how the oil responds to and bends light. Citations are the number of other articles citing this article, calculated by crossref and updated daily. Refractive index of edible oils and fats, why and how to measure it. They are concentrated hydrophobic liquids which obtain essential aroma compounds from plants. Moreover, the quality of oils and fats or oil blends which are used in the production of margarine can be controlled by refractive index measurement. The following normative document contains provisions which, through reference in this text, constitute provisions of this international standard. Pdf refractive index and density measurements of peanut. Prepare a disc shaped sample 14mm in diameter using the hole punch supplied with the solid kit.
Accelerated aging experiments were conducted in a laboratory and increases in the refractive indices of these artificially aged oils were observed. Ici emkarate rl 22h ici emkarate rl 22n 1,452 ici emkarate rl 32s 1,455 ici emkarate rl 32cf 1,455 ici emkarate rl 32h 1,453 ici emkarate rl 68h 1,456 ici emkarate rl. The studied oils are intended to be used as secondary standard oils or as indexmatching fluids for refractive index measurements. Article views are the countercompliant sum of full text article downloads since november 2008 both pdf and html across all institutions and individuals. The measuring prism acts as the refractive index reference. Your article on gemstones and refraction liquids has a refractive index list for fluids frequently used in gemstone testing. Moreover, it helps to differentiate between different essential oils. Mineral oils refractive index is used for defining paraffin to napthene ratios. Refractometric analysis of fats and oils the refractive index or butyro value of animal and vegetable fats and oils is a quickly measured, easily generated quality parameter value. Usually the refractive index of the water is taken as 1. Essentially, it is a measurement that tests how the speed of light is altered when passing through the oil. Pdf the peroxide values and refractive indices of palm olein, sesame oil and sunflower oil were evaluated before deep frying.
Tables of refractive indices by goldsmith, john naish. Manual on oils and fats food safety and standards authority. Refractive index and density measurements of peanut oil for. Effects of repeated deep frying on refractive index and peroxide. This is described by snells law of refraction, n 1 sin. Fats and oils are macronutrients that have a very varied composition. Each material in the database has refractive index listed as a function of wavelength over a range typically required for thinfilm thickness measurement. These measurements can therefore also provide insight into the quality of essential oils, as any change in their optimal composition will affect the refractive index. This section is from the book tables of refractive indices. Pdf a novel method of using refractive index as a tool for. Download our application to learn how easy is measuring refractive index of oils and fats using a mettler toledo refractometer.
Refractive index lab worksheet example answers pdf. Correlation of refractive index and density of crude oil. Determination of refractive index british standard this international standard specifies a method for the determination of the refractive index of essential oils. Standard methods for the analysis of oils, fats and derivatives. Use care not to touch the prism surface with the dropper. A relation between viscosity and refractive index journal. An oils refractive index can be compared to that of a reliable sample. Simply enter 2, 6 or 10 data points of concentration and corresponding ri refractive index value, press compute and the instrument creates a new custom scale. Zeiss microscopy online campus interactive tutorials. The refractive indices of liquid fats have a direct relationship to molecular. Correlation between refractive index of vegetable oils. Specially formulated laser liquid calibration oils that are supplied with an nist certification of traceability. Users can easily blend any two immersion oils from the miscible group to obtain an immersion oil with an intermediate viscosity while maintaining the optical properties common to both.
The present study was designed to correlate the refractive index ri obtained using spr with av obtained using the official aocs method cd 3a63. Refractive indices of water and turpentine oil physics. Essential oils, such as lemon or orange oil, are also referred to as volatile oils. Place instrument so that diffused daylight or some form of artificial light such as na vapor lamp can be used for illumination. Determination of refractive index british standard this international standard specifies a method for the determination of the.
Most objectives in the magnification range between 60x and 100x and higher are designed for use with immersion oil. The refractive index determines how much the path of light is bent, or refracted, when entering a material. Refractive index and density measurements of peanut oil. Ep1142927a1 high refractive index optical silicone oil. Aocs official method cc 725 american oil chemists society. Manufacturers use refractive index as a process control tool. The refractive indices of various oil samples obtained from the field were measured and differences were observed.
For the industry, it is important to know the origin and concentration of its main elements. Milk and milk products or fat coming from milk and milk products are excluded from the scope of this document. Further more the refractive index of fifteen oils has been determined and. Abstract common edible oils and fats refined peanut oil, seasame oil, safflower oil, and butter oil, ghee were exposed to direct sunlight, fluorescent light and. Users can easily blend any two immersion oils from the miscible group to obtain an immersion oil with an intermediate viscosity while maintaining the optical properties common to. Refractive index a refractometer measures the extent to which light is bent i. A higractiveindex optical silicone oil comprising a cyclooligosiloxane having the following formula. The refractive index varies with wavelengths, depending on the degree of oil being analyzed. Refractive index database table of refractive index values. The refractive index of essential oils is a quickly measured, easily generated quality parameter.
Using refractive index to monitor oil quality in high voltage. Correlation of refractive index and density of crude oil and. Refractive index of crude oils is measured as a function of temperature from 20. 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.
Index index instruments limited bury road industrial. Refractive index list of common household liquids gem. These oils are formulated, measured, and certified to five significant places of refractive index 0. Using refractive index to monitor oil quality in high. Refractive index of standard oils as a function of. From table 2 it can be seen that the refractive index of the three types of biodiesel made from rapeseed oil differs from each other by 0. The refractive index of the prism has to be higher than that of the medium under measurement, as otherwise there will be no total internal reflection. Refractive index, peroxide value, vegetable oil, palm olein, sesame oil. Refractive indices of water and turpentine oil physics astronomy project topics, physics science fair projects, pyhsical science, astrology, planets solar experiments for kids and also organics physics science ideas for cbse, icse, gcse, middleschool, elementary school for 5th, 6th, 7th, 8th, 9th and high school students for the year 2016.
The refractive index of the prism has to be higher than that of the medium under measurement. Refractive index, essences and essential oils publisher london, a. Activitylab worksheet example answers 1 determining the refractive index of water. Moreover, it helps to differentiate between different fats, such as butter and margarine. For dated references, subsequent amendments to, or revisions of. The reason of this that ri is material property and defined as the ratio of speed of light in v. Pdf refractive index and density measurements of peanut oil. The product line often times referred to as the cargille liquids or cargille fluids consist of a number of different product groups, each one being made up of a different type of microscopy related product, usually used for characterizing the optical properties of a material. Also, refractive index of 1propanoal and 1butanol as a function of temperature is measured from 20. For example, oil refineries depend on many oils and fats whose origin is different and unknown. Data collected on refractive indices n d 25 show an increase of the order of 0. Publication date 191821 topics refractive index, essences and essential oils publisher. A similar relationship for refractive index at 40c has been developed for highly unsaturated oils from several plant families cruciferae, euphorbiaceae, and labiatae earle et a1. An oil s refractive index can be compared to that of a reliable sample.