{"id":1744,"date":"2025-11-21T10:21:41","date_gmt":"2025-11-21T10:21:41","guid":{"rendered":"https:\/\/pharmacoguide.com\/?p=1744"},"modified":"2025-11-21T10:21:41","modified_gmt":"2025-11-21T10:21:41","slug":"determination-of-refractive-index","status":"publish","type":"post","link":"https:\/\/pharmacoguide.com\/?p=1744","title":{"rendered":"Determination of Refractive Index"},"content":{"rendered":"

Title:<\/strong> Determination of Refractive Index \u00a0<\/strong><\/em><\/span><\/h4>\n

 <\/p>\n

    \n
  1. Objective: <\/strong>To determine the Refractive Index of liquid material.<\/li>\n<\/ol>\n

    \u00a0<\/strong><\/p>\n

      \n
    1. Principle:<\/strong> The\u00a0Refractive Index\u00a0(n<\/em>) of a substance with reference to air is the ratio of the sine of the angle of incidence to the sin of the angle of refraction of a beam of light passing from air into the substance. It varies with the wavelength of the light used in its measurement.<\/li>\n<\/ol>\n\n\n\n
      <\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n

      \u00a0<\/strong><\/p>\n

      3. Procedure: <\/strong><\/p>\n

      Unless otherwise specified in the individual monograph, the refractive index, n<\/em>D<\/sub>20<\/sup>\u00a0is measured at 200\u00a0<\/sup>\u00b1 0.50\u00a0<\/sup>with reference to the wavelength of the D line of sodium (l\u00a0=589.3 nm). The temperature should be carefully adjusted and maintained since the refractive index varies significantly with temperature.<\/p>\n

      The Abbe Refractometer is convenient for most measurements of refractive index but other refractometers of equal or greater accuracy may be used. Commercial refractometer is normally constructed for use with white light but are calibrated to give the refractive index in terms of the D line of sodium. The apparatus is provided with a water jacket to control the temperature of measurement. The manufacturer\u2019s instruction relating to a suitable light source should be followed subject to the directions given in the Pharmacopoeia. To achieve accuracy of \u00b10.0001, the apparatus should be calibrated against distilled water which has a refractive index of 1.3330 at 20\u00b0 and 1.3325 at 25\u00b0 or against the reference liquids given in Table 1.<\/p>\n

      Table 1<\/strong><\/p>\n\n\n\n\n\n\n
      Reference Liquid<\/strong><\/td>\nn<\/em><\/strong>D<\/sub><\/strong>20<\/sup><\/strong><\/td>\nTemperature Coefficient\u00a0\u00a0 \u00a0\u00a0n \/\u00a0 \u00a0t<\/strong><\/td>\n<\/tr>\n
      Carbon tetrachloride<\/td>\n1.4603<\/td>\n– 0.00057<\/td>\n<\/tr>\n
      Toluene<\/td>\n1.4969<\/td>\n– 0.00056<\/td>\n<\/tr>\n
      \u03b1\u00a0-Methylnaphthalene<\/td>\n1.6176<\/td>\n– 0.00048<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n

      *Refractive index value for the D line of Sodium measured at 20\u00b0<\/p>\n

       <\/p>\n

      NOTE \u2013<\/strong> The cleanliness of the instrument should be checked frequently by determining the refractive index of\u00a0distilled water.<\/p>\n

       <\/p>\n

      \n

       <\/p>\n

      “End of Document”<\/span><\/u><\/em><\/h4>\n","protected":false},"excerpt":{"rendered":"

      Title: Determination of Refractive Index \u00a0   Objective: To determine the Refractive Index of liquid material. \u00a0 Principle: The\u00a0Refractive Index\u00a0(n) of a substance with reference to air is the ratio of the sine of the angle of incidence to the sin of the angle of refraction of a beam of light passing from air into […]<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"closed","sticky":false,"template":"templates\/template-full-width.php","format":"standard","meta":{"footnotes":""},"categories":[41],"tags":[],"class_list":["post-1744","post","type-post","status-publish","format-standard","hentry","category-elemental-impurities"],"_links":{"self":[{"href":"https:\/\/pharmacoguide.com\/index.php?rest_route=\/wp\/v2\/posts\/1744","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/pharmacoguide.com\/index.php?rest_route=\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/pharmacoguide.com\/index.php?rest_route=\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/pharmacoguide.com\/index.php?rest_route=\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/pharmacoguide.com\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=1744"}],"version-history":[{"count":1,"href":"https:\/\/pharmacoguide.com\/index.php?rest_route=\/wp\/v2\/posts\/1744\/revisions"}],"predecessor-version":[{"id":1745,"href":"https:\/\/pharmacoguide.com\/index.php?rest_route=\/wp\/v2\/posts\/1744\/revisions\/1745"}],"wp:attachment":[{"href":"https:\/\/pharmacoguide.com\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=1744"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/pharmacoguide.com\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=1744"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/pharmacoguide.com\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=1744"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}