Qualitative Analysis Of Carbohydrate 1u4r1n
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Qualitative Analysis of Carbohydrates
Qualitative Analysis of Carbohydrates Julio Francisco Florida Institute of Technology
1
Qualitative Analysis of Carbohydrates
2
Abstract: The purpose of this experiment was to compare and identify an unknown carbohydrate compound to known carbohydrate samples through various of chemical testing. Theses chemical testings include the Benedict’s test, molisch test, inversion of sucrose, Seliwanoff's test, Bial’s test, and thin layer chromatography (TLC). After performing all the test, the unknown compound was determined to be maltose. However, further testing must be conducted to confirm if the unknown carbohydrate is truly maltose.
Qualitative Analysis of Carbohydrates
3
Introduction: The following experiment was conducted to identify an unknown compound using six different testing techniques. The unknown compound can be determined by comparing the chemical reaction of known carbohydrates by applying various chemical tests. Qualitative data were collected. The known carbohydrates used in this experiment were glucose, fructose, galactose, arabinose, maltose, ribose, xylose, and sucrose. The following is an overall of the applications and usage of each test: Benedict’s Test The Benedict’s test is important to identify reducing sugars. Under an alkali solution, the reducing sugar would be heated resulting in the enolization of sugars. These sugars can potentially reduce Cu2+ to Cu+ which results in precipitation of a red copper(I) oxide. Therefore, the appearance of a red brick solution indicated the presence of a reducing sugar. There are many applications for the Benedict’s test. Since the 1900’s a modified version of Benedict’s test was used to detect glucose in the urine in order to diagnose someone with diabetes mellitus. However, the introduction of Clinistix and TesTape supplanted the use of the Benedict test since Clinistix and TesTape provided a more accurate reading than the Benedict’s test (Ackerman, Williams, Packer,Hawkes, & Abler, 1958). However, due to the limitation of urine glucose monitoring and the rise of blood glucose monitoring, urinary glucose test become less frequently used for detection of diabetes mellitus. Today selfmonitoring of capillary blood glucose is commonly used to determine the blood glucose level for diabetic patient due to a more accurate reading than previous testing techniques (Cowart & Stachura,1990). There are many other applications of the Benedict’s test to discuss; however, such applications is beyond the scope of this paper.
4
Qualitative Analysis of Carbohydrates
Molisch Test The Molisch test is a test for general carbohydrate. In this test, carbohydrate is dehydrate to a furfural derivative in the presence of a concentrated acid (e.g. sulfuric acid). The furfural react with αnaphthol resulting in the formation of a red or violet color. Therefore, a positive test for a carbohydrate is denoted by the appearance of a red or violet colored solution. Researcher generally use the Molisch test to determined the presence of carbohydrate in variety of substances, from elastin protein to unripened guavas (Misra & Seshadri, 1968; Stein & Miller, 1938). Bial’s Test The Bial’s test is a chemical test used to detect the presence of a pentose molecule. If a pentose molecule was presence, then the Bial’s reagent will cause the pentose to dehydrate which result in the formation of furfural. The furfural further react with orcinol to give a bluegreen condensation product. Therefore, the appearance of a bluegreen color solution indicates the presence of a pentose molecule. Seliwanoff's Test for Ketose The Seliwanoff's test is used to detect the presence of ketose. If the ketose is presence, then the Seliwanoff’s reagent would dehydrate the ketose and form hydroxymethyl furfural. The hydroxymethyl furfural will further react with resorcinol giving off a red condensation product. Therefore, the presence of a ketose molecule is indicated by the formation of a red colored solution.
5
Qualitative Analysis of Carbohydrates
TLC for Carbohydrate TLC is a technique used to separate molecule from a complex mixture based on particular properties of the compounds (e.g. adsorption). Some of the advantage of using TLC method is the fact it is simple, expedient, inexpensive, and effective method of separation (Tyrpień, Bodzek, & Manka, 2001). The applications of TLC technique is so profound that it will go beyond the scope of the paper. Experimental Procedure: Benedict’s Test In the Benedict’s test, 5 ml of Benedict’s reagent was added to 5 test tubes. Then, 1 ml of 0.1 M of glucose, maltose, arabinose, sucrose, and xylose were individual to each test tube. Place in boiling water bath for 5 to 50 minutes. Any color change was observed. Molisch Test In the Molisch test, 5 ml of 1:10 dilution of glucose, fructose, galactose, maltose, arabinose, ribose, xylose, sucrose, and two unknowns were placed into individual test tubes. Next, 2 drops of Molisch reagent and 3 ml of concentrated H2SO4 were added and observation was recorded. Bial’s Test For the Bial’s test, add 5 ml of Bial’s reagent to 1 ml aliquots of 0.01 M glucose, fructose, arabinose, ribose , and sucrose. Place in boiling water bath for fifteen minutes. Record appearance.
6
Qualitative Analysis of Carbohydrates
Seliwanoff's Test for Ketose For the Seliwanoff’s test, add 5 ml of Seliwanoff’s reagent to 1.0 ml aliquots of 0.01 M solutions of glucose, fructose, sucrose, galactose, and ribose. Place in boiling water bath for fifteen minutes. Record any changes in appearance. Inversion of Sucrose For the inversion of sucrose, add 5 ml of 0.1 M solutions of glucose, fructose, maltose, arabinose, ribose, xylose, sucrose, and unknown solutions into two different test tubes. Add 5 drop of concentrated HCl to one test tube and heat both tube in boiling water bath for 10 minutes. Afterward, add 5 ml of benedict’s reagent to test the presence of reducing sugar. ThinLayer Chromatography of Carbohydrate In the TLC experiment, spot 0.1 M of sugar solutions and the unknown solutions with a capillary tube onto an activated silica gel plate. Allow the spot to dry. After the spot has been dried, place the plate into a glass block chromatocab filled with solvent to the 0.5 cm level. Allow the solvent to rise for twenty minutes. Remove the plate from the from the chromatocab in order for the plates to be analysis. Results: Table 1. Carbohydrate Identification Table. The following table demonstrate the observation for each test applied on individual carbohydrates. The shaded regions represent the omission of certain carbohydrate from certain test. Carbohydrate
Benedict’s Test
Molish Test
Bial’s Test
Glucose
Red Precipitate Formed
Brown Color Light peach color
Seliwanoff's Test
Inversion of Sucrose
Gold color
No change
7
Qualitative Analysis of Carbohydrates
Fructose
Dark brown color
Dark red color
Bloody red color
No change
Galactose
Red color
Light yellow
No change
Maltose
Amber color with precipitation in the bottom
Red color
No change
Arabinose
Amber color with precipitation in the bottom
Dark Red color
Yellow color
No change
Ribose
Light brown color
Light silver color
Dark yellow color
No change
Xylose
Brown color
No change
Sucrose
No color change
Red color
Dark red color
Bloody red color
Sucrose was a darker hue in comparison to other carbohydrate compounds
Unknown 1
A fusion of amber and blue color with precipitation formation
Red color
Peach color
Peach
No change
Unknown 2
Unknown 3
Unknown 4
Six carbohydrate identification tests were performed and the observation was recorded (Table 1). First, the molisch test was used to detect any carbohydrate. A positive result for the molisch test is indicated by the appearance of a red to violet color. Among all carbohydrate
Qualitative Analysis of Carbohydrates
8
tested, four carbohydrates changed to a red color. This includes galactose, maltose, arabinose, and sucrose. On the other hand, glucose, fructose, ribose, and xylose changed to a brownish color. The next test was the Benedict’s test which is common use to detect reducing sugars. A positive test for the Benedict’s test is indicated by the formation of yellow, green, or red precipitation. Glucose, maltose, arabinose, and unknown are the only carbohydrates that indicated a positive result for the benedict’s test. Furthermore, sucrose did not showed any color changes. The third test was the Bial’s test which is used to detect the presence of pentose. The presence of a pentose is indicated by the appearance of greenblue or olivegreen color. The Bial’s test was conducted on solutions with glucose, fructose, arabinose, ribose, sucrose, and an unknown compound. None of the compounds gave an indication of a pentose. The next experiment conducted was the Seliwanoff’s test. The Seliwanoff’s test is used to detect the presence of a ketose. A positive result is indicated by the appearance of red color. Fructose and sucrose are the only two compounds that gave a positive result for the presence of ketose. The last test was the inverse of sucrose. Sucrose was the only carbohydrate that produced a different darker blue than other carbohydrate solution.
Qualitative Analysis of Carbohydrates
9
Figure 1.Thin Layer chromatography analysis of glucose, fructose, galactose, maltose, arabinose, ribose, xylose, sucrose, and unknown 1, 2, and 3. Solutions of 0.1 M of sugar compound were spotted onto a silicabased gel plate and allowed to dry. Once dried, the spotted plates were transferred into a glass chromatocab containing of approximately 500 mL solvent. The solvent consist of chloroform, glacial acetic acid, and water (v/v 30:35:5). The solvent was allowed to run to a height of 7 cm for approximately 20 minutes. Next, the plate was removed from the chromatocab for further analysis. It was determined that unknown 1 had similar migration pattern as maltose. A thin layer chromatography was conducted to identify the unknown compounds by comparing spots of the unknown compounds to known carbohydrate solution (Fig. 1). It was observed that unknown 1 traveled the same distance as maltose. Furthermore, unknown 3
Qualitative Analysis of Carbohydrates
10
traveled the same distance as galactose, and unknown 4 travel similar distance as arabinose. Unknown 2 did not appeared in the TLC. Discussion: The first test was the Benedict’s test. The Benedict’s test is used to identify the presence of reducing sugar. A positive result is denoted by the formation of a yellow, green, or red precipitate. In the Benedict’s experiment, it was revealed that glucose, maltose, and arabinose gave a positive result for such test. On the other hand, ribose and sucrose gave a negative result indicating that the these two carbohydrates are nonreducing sugars. The result for the Benedict’s experiment was consistent with known facts. Also, the Benedict’s test indicated that the unknown compound is a reducing sugar. The second test was the Molisch test which is an eminent test used to detect the presence of soluble carbohydrate. A red to violet color is a positive indication of a carbohydrate. It was expected that all of the carbohydrate used would give a positive result. However, only galactose, maltose, arabinose, and sucrose gave a positive result. Glucose, fructose, ribose, and xylose gave a negative result. This may be due to the action of sulfuric acid (Dreywood, 1946). Since the carbohydrate was “burned” by the sulfuric acid, further testing must be conducted to ensure that experiment was performed properly. Furthermore, the unknown compound gave a positive result indicating that the unknown compound is a carbohydrate. The next test performed was the Bial’s test which is used to detect the presence of pentoses. The presence of pentose is indicated by the appearance of a bluishgreen or olivegreen color. None of the compounds gave a positive result for the Bial’s test. This is unexpected since arabinose, ribose, xylose are pentose molecules and, therefore, these molecules should indicated
Qualitative Analysis of Carbohydrates
11
a positive result for the Bial’s test. It can be assumed that the there might be an error that occurred in the experiment. The Seliwanoff’s test is used to detect the presence of ketoses. The compounds that gave a positive result were fructose and sucrose. It was unexpected to see that sucrose received a positive result due to the fact that sucrose is a disaccharide composed of both glucose and fructose. It can be postulate that the Seliwanoff's reagent reacted with the fructose component of sucrose leading to a positive result. Furthermore, the unknown compound did not gave a positive result for the Seliwanoff’s test, and therefore, the unknown compound could be potential be a pentose. In the inversion of sucrose, the only compound that changed appearance was sucrose. Invert sugar is the process of breaking down sugar, such as sucrose, into its individual monosaccharide components. Since sucrose is the only disaccharide used in this experiment that can be broken down, the result was consistent with the expected. Also, this test indicates that the unknown compound is not a sucrose molecule since the compound does not undergo the process of inversion. The last experiment was the thinlayer chromatography. Based on the migration pattern, unknown 1 traveled the same distance as maltose. This indicated that the unknown compound may be maltose. Based on all the experimental tests performed, unknown 1 is a nonsucrose, reducing sugar. Also, the unknown compound can potential be a pentose; however, the Bial’s test must be perform properly to confirm that the unknown compound is truly a pentose molecule. With these information in mind, it can be postulate that unknown 1 is truly maltose.
Qualitative Analysis of Carbohydrates
12
Unknown 2,3, and 4 cannot be identified due to the lack of data. Further improvement must be made for future experiments. In particular, additional trials must be conducted to determine if the experiment is valid. Only one trial was performed in this experiment which does not give a good representation of the test performed and, therefore, addition trials is essential.
Qualitative Analysis of Carbohydrates
13
References: Ackerman, R. F., Williams, E. F., Packer, H., Hawkes, J. H., & Abler, J. (1958). Comparison of benedict's solution, clinitest, testape and clinistix. Diabetes, 7(5), 398402. doi:10.2337/diab.7.5.398 Cowart, S. L., Stachura, M. E. (1990). Glucosuria. In Walker H.K., Hall W.D., Hurst J.W. (Ed.), Clinical methods: The history, physical, and laboratory examinations (3rd ed., pp. 653657). Boston: Butterworths. Dreywood, R. (1946). Qualitative Test for Carbohydrate Material. Industrial & Engineering Chemistry Analytical Edition,18 (8), 499499. DOI: 10.1021/i560156a015. Experiment 5: Chemical Properties of Carbohydrate. Misra, K. & Seshadri, T. R. (1968). Chemical components of the fruits of psidium guava. Phytochemistry, 7(4), 641–645. doi:10.1016/S00319422(00)882400 Stein, W. H., & Miller, E. G. (1938). The composition of elastin. Journal of Biological Chemistry, 125(2), 599614. Tyrpień, K., Bodzek, P., & Manka, G. (2001). Biomedical Chromatography : BMC, 15, 50. DOI:10.1081/SPM120025026
Qualitative Analysis of Carbohydrates Julio Francisco Florida Institute of Technology
1
Qualitative Analysis of Carbohydrates
2
Abstract: The purpose of this experiment was to compare and identify an unknown carbohydrate compound to known carbohydrate samples through various of chemical testing. Theses chemical testings include the Benedict’s test, molisch test, inversion of sucrose, Seliwanoff's test, Bial’s test, and thin layer chromatography (TLC). After performing all the test, the unknown compound was determined to be maltose. However, further testing must be conducted to confirm if the unknown carbohydrate is truly maltose.
Qualitative Analysis of Carbohydrates
3
Introduction: The following experiment was conducted to identify an unknown compound using six different testing techniques. The unknown compound can be determined by comparing the chemical reaction of known carbohydrates by applying various chemical tests. Qualitative data were collected. The known carbohydrates used in this experiment were glucose, fructose, galactose, arabinose, maltose, ribose, xylose, and sucrose. The following is an overall of the applications and usage of each test: Benedict’s Test The Benedict’s test is important to identify reducing sugars. Under an alkali solution, the reducing sugar would be heated resulting in the enolization of sugars. These sugars can potentially reduce Cu2+ to Cu+ which results in precipitation of a red copper(I) oxide. Therefore, the appearance of a red brick solution indicated the presence of a reducing sugar. There are many applications for the Benedict’s test. Since the 1900’s a modified version of Benedict’s test was used to detect glucose in the urine in order to diagnose someone with diabetes mellitus. However, the introduction of Clinistix and TesTape supplanted the use of the Benedict test since Clinistix and TesTape provided a more accurate reading than the Benedict’s test (Ackerman, Williams, Packer,Hawkes, & Abler, 1958). However, due to the limitation of urine glucose monitoring and the rise of blood glucose monitoring, urinary glucose test become less frequently used for detection of diabetes mellitus. Today selfmonitoring of capillary blood glucose is commonly used to determine the blood glucose level for diabetic patient due to a more accurate reading than previous testing techniques (Cowart & Stachura,1990). There are many other applications of the Benedict’s test to discuss; however, such applications is beyond the scope of this paper.
4
Qualitative Analysis of Carbohydrates
Molisch Test The Molisch test is a test for general carbohydrate. In this test, carbohydrate is dehydrate to a furfural derivative in the presence of a concentrated acid (e.g. sulfuric acid). The furfural react with αnaphthol resulting in the formation of a red or violet color. Therefore, a positive test for a carbohydrate is denoted by the appearance of a red or violet colored solution. Researcher generally use the Molisch test to determined the presence of carbohydrate in variety of substances, from elastin protein to unripened guavas (Misra & Seshadri, 1968; Stein & Miller, 1938). Bial’s Test The Bial’s test is a chemical test used to detect the presence of a pentose molecule. If a pentose molecule was presence, then the Bial’s reagent will cause the pentose to dehydrate which result in the formation of furfural. The furfural further react with orcinol to give a bluegreen condensation product. Therefore, the appearance of a bluegreen color solution indicates the presence of a pentose molecule. Seliwanoff's Test for Ketose The Seliwanoff's test is used to detect the presence of ketose. If the ketose is presence, then the Seliwanoff’s reagent would dehydrate the ketose and form hydroxymethyl furfural. The hydroxymethyl furfural will further react with resorcinol giving off a red condensation product. Therefore, the presence of a ketose molecule is indicated by the formation of a red colored solution.
5
Qualitative Analysis of Carbohydrates
TLC for Carbohydrate TLC is a technique used to separate molecule from a complex mixture based on particular properties of the compounds (e.g. adsorption). Some of the advantage of using TLC method is the fact it is simple, expedient, inexpensive, and effective method of separation (Tyrpień, Bodzek, & Manka, 2001). The applications of TLC technique is so profound that it will go beyond the scope of the paper. Experimental Procedure: Benedict’s Test In the Benedict’s test, 5 ml of Benedict’s reagent was added to 5 test tubes. Then, 1 ml of 0.1 M of glucose, maltose, arabinose, sucrose, and xylose were individual to each test tube. Place in boiling water bath for 5 to 50 minutes. Any color change was observed. Molisch Test In the Molisch test, 5 ml of 1:10 dilution of glucose, fructose, galactose, maltose, arabinose, ribose, xylose, sucrose, and two unknowns were placed into individual test tubes. Next, 2 drops of Molisch reagent and 3 ml of concentrated H2SO4 were added and observation was recorded. Bial’s Test For the Bial’s test, add 5 ml of Bial’s reagent to 1 ml aliquots of 0.01 M glucose, fructose, arabinose, ribose , and sucrose. Place in boiling water bath for fifteen minutes. Record appearance.
6
Qualitative Analysis of Carbohydrates
Seliwanoff's Test for Ketose For the Seliwanoff’s test, add 5 ml of Seliwanoff’s reagent to 1.0 ml aliquots of 0.01 M solutions of glucose, fructose, sucrose, galactose, and ribose. Place in boiling water bath for fifteen minutes. Record any changes in appearance. Inversion of Sucrose For the inversion of sucrose, add 5 ml of 0.1 M solutions of glucose, fructose, maltose, arabinose, ribose, xylose, sucrose, and unknown solutions into two different test tubes. Add 5 drop of concentrated HCl to one test tube and heat both tube in boiling water bath for 10 minutes. Afterward, add 5 ml of benedict’s reagent to test the presence of reducing sugar. ThinLayer Chromatography of Carbohydrate In the TLC experiment, spot 0.1 M of sugar solutions and the unknown solutions with a capillary tube onto an activated silica gel plate. Allow the spot to dry. After the spot has been dried, place the plate into a glass block chromatocab filled with solvent to the 0.5 cm level. Allow the solvent to rise for twenty minutes. Remove the plate from the from the chromatocab in order for the plates to be analysis. Results: Table 1. Carbohydrate Identification Table. The following table demonstrate the observation for each test applied on individual carbohydrates. The shaded regions represent the omission of certain carbohydrate from certain test. Carbohydrate
Benedict’s Test
Molish Test
Bial’s Test
Glucose
Red Precipitate Formed
Brown Color Light peach color
Seliwanoff's Test
Inversion of Sucrose
Gold color
No change
7
Qualitative Analysis of Carbohydrates
Fructose
Dark brown color
Dark red color
Bloody red color
No change
Galactose
Red color
Light yellow
No change
Maltose
Amber color with precipitation in the bottom
Red color
No change
Arabinose
Amber color with precipitation in the bottom
Dark Red color
Yellow color
No change
Ribose
Light brown color
Light silver color
Dark yellow color
No change
Xylose
Brown color
No change
Sucrose
No color change
Red color
Dark red color
Bloody red color
Sucrose was a darker hue in comparison to other carbohydrate compounds
Unknown 1
A fusion of amber and blue color with precipitation formation
Red color
Peach color
Peach
No change
Unknown 2
Unknown 3
Unknown 4
Six carbohydrate identification tests were performed and the observation was recorded (Table 1). First, the molisch test was used to detect any carbohydrate. A positive result for the molisch test is indicated by the appearance of a red to violet color. Among all carbohydrate
Qualitative Analysis of Carbohydrates
8
tested, four carbohydrates changed to a red color. This includes galactose, maltose, arabinose, and sucrose. On the other hand, glucose, fructose, ribose, and xylose changed to a brownish color. The next test was the Benedict’s test which is common use to detect reducing sugars. A positive test for the Benedict’s test is indicated by the formation of yellow, green, or red precipitation. Glucose, maltose, arabinose, and unknown are the only carbohydrates that indicated a positive result for the benedict’s test. Furthermore, sucrose did not showed any color changes. The third test was the Bial’s test which is used to detect the presence of pentose. The presence of a pentose is indicated by the appearance of greenblue or olivegreen color. The Bial’s test was conducted on solutions with glucose, fructose, arabinose, ribose, sucrose, and an unknown compound. None of the compounds gave an indication of a pentose. The next experiment conducted was the Seliwanoff’s test. The Seliwanoff’s test is used to detect the presence of a ketose. A positive result is indicated by the appearance of red color. Fructose and sucrose are the only two compounds that gave a positive result for the presence of ketose. The last test was the inverse of sucrose. Sucrose was the only carbohydrate that produced a different darker blue than other carbohydrate solution.
Qualitative Analysis of Carbohydrates
9
Figure 1.Thin Layer chromatography analysis of glucose, fructose, galactose, maltose, arabinose, ribose, xylose, sucrose, and unknown 1, 2, and 3. Solutions of 0.1 M of sugar compound were spotted onto a silicabased gel plate and allowed to dry. Once dried, the spotted plates were transferred into a glass chromatocab containing of approximately 500 mL solvent. The solvent consist of chloroform, glacial acetic acid, and water (v/v 30:35:5). The solvent was allowed to run to a height of 7 cm for approximately 20 minutes. Next, the plate was removed from the chromatocab for further analysis. It was determined that unknown 1 had similar migration pattern as maltose. A thin layer chromatography was conducted to identify the unknown compounds by comparing spots of the unknown compounds to known carbohydrate solution (Fig. 1). It was observed that unknown 1 traveled the same distance as maltose. Furthermore, unknown 3
Qualitative Analysis of Carbohydrates
10
traveled the same distance as galactose, and unknown 4 travel similar distance as arabinose. Unknown 2 did not appeared in the TLC. Discussion: The first test was the Benedict’s test. The Benedict’s test is used to identify the presence of reducing sugar. A positive result is denoted by the formation of a yellow, green, or red precipitate. In the Benedict’s experiment, it was revealed that glucose, maltose, and arabinose gave a positive result for such test. On the other hand, ribose and sucrose gave a negative result indicating that the these two carbohydrates are nonreducing sugars. The result for the Benedict’s experiment was consistent with known facts. Also, the Benedict’s test indicated that the unknown compound is a reducing sugar. The second test was the Molisch test which is an eminent test used to detect the presence of soluble carbohydrate. A red to violet color is a positive indication of a carbohydrate. It was expected that all of the carbohydrate used would give a positive result. However, only galactose, maltose, arabinose, and sucrose gave a positive result. Glucose, fructose, ribose, and xylose gave a negative result. This may be due to the action of sulfuric acid (Dreywood, 1946). Since the carbohydrate was “burned” by the sulfuric acid, further testing must be conducted to ensure that experiment was performed properly. Furthermore, the unknown compound gave a positive result indicating that the unknown compound is a carbohydrate. The next test performed was the Bial’s test which is used to detect the presence of pentoses. The presence of pentose is indicated by the appearance of a bluishgreen or olivegreen color. None of the compounds gave a positive result for the Bial’s test. This is unexpected since arabinose, ribose, xylose are pentose molecules and, therefore, these molecules should indicated
Qualitative Analysis of Carbohydrates
11
a positive result for the Bial’s test. It can be assumed that the there might be an error that occurred in the experiment. The Seliwanoff’s test is used to detect the presence of ketoses. The compounds that gave a positive result were fructose and sucrose. It was unexpected to see that sucrose received a positive result due to the fact that sucrose is a disaccharide composed of both glucose and fructose. It can be postulate that the Seliwanoff's reagent reacted with the fructose component of sucrose leading to a positive result. Furthermore, the unknown compound did not gave a positive result for the Seliwanoff’s test, and therefore, the unknown compound could be potential be a pentose. In the inversion of sucrose, the only compound that changed appearance was sucrose. Invert sugar is the process of breaking down sugar, such as sucrose, into its individual monosaccharide components. Since sucrose is the only disaccharide used in this experiment that can be broken down, the result was consistent with the expected. Also, this test indicates that the unknown compound is not a sucrose molecule since the compound does not undergo the process of inversion. The last experiment was the thinlayer chromatography. Based on the migration pattern, unknown 1 traveled the same distance as maltose. This indicated that the unknown compound may be maltose. Based on all the experimental tests performed, unknown 1 is a nonsucrose, reducing sugar. Also, the unknown compound can potential be a pentose; however, the Bial’s test must be perform properly to confirm that the unknown compound is truly a pentose molecule. With these information in mind, it can be postulate that unknown 1 is truly maltose.
Qualitative Analysis of Carbohydrates
12
Unknown 2,3, and 4 cannot be identified due to the lack of data. Further improvement must be made for future experiments. In particular, additional trials must be conducted to determine if the experiment is valid. Only one trial was performed in this experiment which does not give a good representation of the test performed and, therefore, addition trials is essential.
Qualitative Analysis of Carbohydrates
13
References: Ackerman, R. F., Williams, E. F., Packer, H., Hawkes, J. H., & Abler, J. (1958). Comparison of benedict's solution, clinitest, testape and clinistix. Diabetes, 7(5), 398402. doi:10.2337/diab.7.5.398 Cowart, S. L., Stachura, M. E. (1990). Glucosuria. In Walker H.K., Hall W.D., Hurst J.W. (Ed.), Clinical methods: The history, physical, and laboratory examinations (3rd ed., pp. 653657). Boston: Butterworths. Dreywood, R. (1946). Qualitative Test for Carbohydrate Material. Industrial & Engineering Chemistry Analytical Edition,18 (8), 499499. DOI: 10.1021/i560156a015. Experiment 5: Chemical Properties of Carbohydrate. Misra, K. & Seshadri, T. R. (1968). Chemical components of the fruits of psidium guava. Phytochemistry, 7(4), 641–645. doi:10.1016/S00319422(00)882400 Stein, W. H., & Miller, E. G. (1938). The composition of elastin. Journal of Biological Chemistry, 125(2), 599614. Tyrpień, K., Bodzek, P., & Manka, G. (2001). Biomedical Chromatography : BMC, 15, 50. DOI:10.1081/SPM120025026
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