Osazone test

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Osazone test

  1. 1. OSAZONE TEST <br />
  2. 2. Introduction<br />The technique was developed by Emil Fischer, , a German chemist.<br />
  3. 3. Introduction<br />Phenylhydrazine is the chemical compound with the formula C6H5NHNH2. <br />
  4. 4. Introduction<br />Osazones are formed when the sugars react with a <br />compound known as phenylhydrazine at boiling point.<br />General Reaction:<br />
  5. 5. Introduction<br />These sugars are reducing ones which have either a free aldehyde or a ketone group to react with the phenylhydrazine. <br />
  6. 6. Procedures<br />1. Pipette 1 ml of the phenylhydrazine mixture to a test tube.<br />
  7. 7. Procedures<br />2. Add 5 ml of the test solution<br />
  8. 8. Procedures<br />3. shake vigorously to insure complete solution<br />
  9. 9. Procedures<br />4. Stopper the mouth of the tube loosely with cotton<br />
  10. 10. Procedures<br />5. Place the tube immediately in a boiling water bath<br />
  11. 11. Procedures<br />6. Record the time<br />
  12. 12. Procedures<br />7. Observe the tube<br />
  13. 13. Procedures<br />8. If a precipitate is formed, record the time and remove the tube from the bath<br />
  14. 14. Procedures<br />9. Cool off the tube <br />
  15. 15. Procedures<br />10. Examine the crystals under low power objective <br />
  16. 16. Results and Discussions<br />The reaction is stepwise;<br />
  17. 17. Osazone formation involves hydrazone formation at C-1 of an aldose (or C-2 of a ketose) and oxidation of C-2 (or C-1) of an alcohol group to a ketone (or an aldehyde). The new carbonyl group is also converted to a hydrazone. <br />Mannose<br />Glucose<br />Fructose<br />
  18. 18. Osazone crystals have a characteristic shape under the light microscope and help in the identification of the sugar type.<br />Monosaccharides - like needle-shaped or broomstick<br />Disaccharides - like sunflowers<br />Lactose - like tight balls of needles<br />
  19. 19. Making Osazone Crystals<br />The difference in the structure of the monosaccharides is caused by the diverse groups attached to the first and second carbons of the sugar molecules. Their needle-shaped crystals show that the position of the first and second carbons do not matter in the crystal formation.<br />
  20. 20. Viewed under the microscope: Glucosazone<br />
  21. 21. Viewed under the microscope: Fructosazone<br />
  22. 22. Viewed under the microscope: Galactosazone<br />
  23. 23. Viewed under the microscope: Maltosazone<br />
  24. 24. Viewed under the microscope: Xylosazone<br />
  25. 25. Viewed under the microscope: Sucrose<br />
  26. 26. Time to Form<br />The time needed to create osazone crystals varies among the various sugars involved, but helps to identify the sugars being tested. For an osazone crystal to be presented from a hot solution will take as long as follows:<br /><ul><li>fructose, two minutes;
  27. 27. glucose, four to five minutes;
  28. 28. xylose, seven minutes;
  29. 29. galactose, 15-19 minutes;
  30. 30. maltose, osazone soluble in hot water
  31. 31. Actual Time:
  32. 32. Xylose – 20 mins
  33. 33. Galactose – 25 mins
  34. 34. Glucose – 30 mins
  35. 35. Sucrose – 47 mins
  36. 36. Fructose – 57 mins
  37. 37. Maltose – 59 mins</li></li></ul><li>Application<br />For identifying sugars esp. Reducing sugars.<br />Osazones are used as dyes<br />
  38. 38. References<br />http://www.ehow.com/info_8392949_different-osazone-crystals.html#ixzz1Rx9lFGBJ<br />http://www.pua.edu.eg/Version2/Courses2/Dentistry%20Courses/Freshmen/Spring/BCM101/Practical/Week%202%20practical%20_Chemistry%20of%20carbohydrates_.pdf<br />http://www.chemistry.ccsu.edu/glagovich/teaching/316/qualanal/tests/osazone.html<br />

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