Preview

Qualitative Tests of Carbohydrates

Better Essays
Open Document
Open Document
1231 Words
Grammar
Grammar
Plagiarism
Plagiarism
Writing
Writing
Score
Score
Qualitative Tests of Carbohydrates
QUALITATIVE TESTS OF CARBOHYDRATES
Final Lab Report

Submitted by

Brittany Fitzgerald
545301

Prepared for

Nancy Cook
Chemistry 3501
Monday

November 26, 2012

RESULTS
PART A:
As a result of the Benedict’s test on various sugar solutions, it was found that galactose, mannose, arabinose, ribose, lactose, fructose, maltose, and cellobiose tested positively and therefore are considered reducing sugars. Glucose, starch, sucrose, and methyl-D-glucopyranoside on the other hand tested negatively and therefore are considered non-reducing sugars.
Table 1. Results of Benedict’s test on various sugar solutions Sugar Solution | Color | Clarity | Glucose | Bright blue with orange tint on top | Clear | Galactose | Brown on top, blue-ish on bottom | Opaque | Mannose | Brown on top and bottom, green/blue in middle | Opaque | Arabinose | Brown/copper on top, blue/green on bottom | Opaque | Ribose | Brown/green throughout | Opaque | Lactose | Brown on top and bottom, blue-ish in middle | Opaque | Fructose | Brown/green throughout, red on bottom | Opaque | Maltose | Green/blue throughout, red on bottom | Opaque | Cellobiose | Green/blue through, red on bottom | Opaque | Starch | Bright blue | Clear | Sucrose | Bright blue | Clear | Methyl-D-glucopyranoside | Bright blue | Clear |

PART B:
As a result of the Seliwanoff’s test on various carbohydrates, it was found that only fructose and sucrose tested positively and therefore they are considered ketoses.

Table 2. Results of Seliwanoff’s test after 1 minute Carbohydrate/Water | Color | Glucose | Colorless | Fructose | Colorless | Sucrose | Colorless | Water | Colorless |

Table 3. Results of Seliwanoff’s test after 2 minutes Carbohydrate/Water | Color | Glucose | Colorless | Fructose | Light pink/red | Sucrose | Colorless | Water | Colorless |

Table 4. Results of Seliwanoff’s test after 3 minutes


References: Eaton, David C. 1989. “Experiment 33: Carbohydrates.” Accessed November 17. http://moodlelive.msvu.ca/file.php/5622/Carbohydrates.pdf Mount Saint Vincent University. 2012. “Chemistry 3501 Lab Manual”. Nova Scotia: Halifax. Schreck, James O., Loffredo, William M. 2012. “Qualitative Testing for Carbohydrates.” Accessed November 16. http://kurdchemists.org/files/carbohydrates%20test%20new.pdf
Continue Reading
View Writing Issues

You May Also Find These Documents Helpful

  • Good Essays

    Erlenmeyer Synthesis
    • 998 Words
    • 4 Pages

    Erlenmeyer Synthesis

    The Fehling’s test was done to show the presence of carbohydrates. Two small test tubes were used and 5 mL of Fehling’s reagent was added to it. Five drops of 1% glucose was added to one test tube, the control. This tube was then boiled and if a brown-red precipitate was formed, it would indicate that there was a carbohydrate present. The other tube had 5 mL of the Fehling’s reagent put in it and five drops of the filtrate after the ethyl acetate was gone and the filtrate had been cooled. If this created a brown-red precipitate, it would indicate that there was a carbohydrate…

    • 998 Words
    • 4 Pages
    Good Essays
    Read More
  • Satisfactory Essays

    Brounian movment
    • 352 Words
    • 2 Pages

    Brounian movment

    Lugol's solution is a solution of elemental iodine and potassium iodide in water, and it’s been used in this experiment as a reagent for starch detection. Benedict's reagent has been used as a test for the presence of reducing sugar, which include lactose and maltose.…

    • 352 Words
    • 2 Pages
    Satisfactory Essays
    Read More
  • Satisfactory Essays

    Carbohydrate Fermentation Testing
    • 412 Words
    • 2 Pages

    Carbohydrate Fermentation Testing

    Acid production produces a color change from red to yellow, indicating the organism is capable of metabolizing the sugar in the tube…

    • 412 Words
    • 2 Pages
    Satisfactory Essays
    Read More
  • Powerful Essays

    Spit Lab
    • 2637 Words
    • 11 Pages

    Spit Lab

    The objective for the Spit lab was to test two different types of crackers for the presence or absence of starch and of reducing sugars. Also, to test the chewed cracker, the one that didn’t have a reducing sugar, for the presence or absence of a reducing sugar with the saliva in it. Adding on, another part of the objective is to determine the effect of amylase on starch. For the Chemical Aspects lab, the objectives were to test for the presence or absence of carbohydrates, lipids and proteins in several test samples. In the starch test, the objective was to find the substances that contain starch. In the starch test, iodine was used. In the reducing sugar test, the objective was to find the test materials that have a reducing sugar. In the reducing sugar test benedicts was used. In the grease spot test, the objective was to find all the samples that had a lipid. Another one of the lipid tests were the dye test which was a more specific test to find the substances that all contained a fat by using a solution of Sudan 4 and water. The protein test’s purpose was to determine all the test materials that contained a protein by using biuret solution. The procedure for the Spit lab was to perform the starch test and reducing sugar test on both crackers. Then chew up the cracker that doesn’t have reducing sugars. Next, test the sample for a reducing sugar. The results of the Chemical Aspects lab were that starch, potato juice, cracker solution, and cereal contain starch. In the reducing sugar test glucose, fructose, lactose, and milk contain a reducing sugar. In the grease spot test, salad oil, milk, and chips are lipids. In the dye test, salad oil and chips are fats. Egg albumin, cereal, and cracker mixture show that they are proteins. In the Spit lab the saliva and cracker test showed up positive. The starch test for saltine was positive. The reducing sugar test for saltine was…

    • 2637 Words
    • 11 Pages
    Powerful Essays
    Read More
  • Good Essays

    Glucose and Identifying Nutrients Gizmo
    • 973 Words
    • 4 Pages

    Glucose and Identifying Nutrients Gizmo

    Note: Disaccharides such as sucrose (table sugar) and lactose (milk sugar) are more complex than monosaccharides. The Benedict test does detect disaccharides directly.…

    • 973 Words
    • 4 Pages
    Good Essays
    Read More
  • Satisfactory Essays

    Sucrose Decisions
    • 74 Words
    • 1 Page

    Sucrose Decisions

    Note: in the “Going sugar-free” series, when saying “sugar”, I am referring to “table sugar” also known as “sucrose”, extracted from sugarcane or beet sugar.…

    • 74 Words
    • 1 Page
    Satisfactory Essays
    Read More
  • Good Essays

    Carbohydrate Counting Essay
    • 452 Words
    • 2 Pages

    Carbohydrate Counting Essay

    If you take at least three or four doses of insulin a day or use an in-…

    • 452 Words
    • 2 Pages
    Good Essays
    Read More
  • Satisfactory Essays

    Kestose And Neokestose Research Paper
    • 279 Words
    • 2 Pages

    Kestose And Neokestose Research Paper

    The main trisaccharides (raffinose, kestoses and theanderose) isolated from cane sugar are composed primarily of a monosaccharide molecule (glucose/fructose/galactose) bonded to a molecule of sucrose. The kestoses (1-, 6- and neo-) are composed of a fructose molecule attached to a sucrose molecule (Figure 6). The kestoses (1-kestose, 6-kestose and neokestose) are formed by the addition of a fructosyl residue to a sucrose molecule. The emergence of the different kestose isomers arises from the substitution of the fructosyl residue on any one of the three primary alcohol groups on the sucrose molecule (Suzuki & Chatterton, 1993). The 6-kestose isomer arises from the glycosidic linkage of the fructose residue of sucrose in position 6 to an additional fructose molecule in the 2β position (6→2β) (Heldt, H. & Heldt, F,…

    • 279 Words
    • 2 Pages
    Satisfactory Essays
    Read More
  • Satisfactory Essays

    Osmosis and Diffusion Lab
    • 275 Words
    • 2 Pages

    Osmosis and Diffusion Lab

    Iodine molecules entered the sack, while glucose molecules left the sack. When the iodine came in contact with the starch and changed color, the Iodine was entering the sack. You can tell the direction of the iodine by looking at the changing colors. The starch molecules remained in the sack because they were too large to pass through, so they couldn’t leave the sack. The glucose was able to get out of the sack, we know this because we tested the water with a test stick and it came back with a glucose positive result. Some molecules were able to move through the sack simply because they were smaller than others, but the starch molecules were unable because they were too large o pass. Finally, Diffusion is the net movement of particles from an area where there are many particles of the substance to an area where there are fewer.…

    • 275 Words
    • 2 Pages
    Satisfactory Essays
    Read More
  • Powerful Essays

    Sucralose: the Effects on the Human Body
    • 1230 Words
    • 5 Pages

    Sucralose: the Effects on the Human Body

    By substituting article sweeteners for the real thing, individuals are able to satisfy their sweet tooth without packing on the pounds or suffering from sugar related health problems. This idea has resulted in an expanding number of forms of artificial sugars entering the food market. Along with the explosion of options has come a controversy as to whether these sugar substitutes are a healthy alternative, or if they may be having their own negative effects on our health. In this paper, I will explore the possible effects of one of these sugar substitute Sucralose, and present why I believe it is a safe alternative to table sugar.…

    • 1230 Words
    • 5 Pages
    Powerful Essays
    Read More
  • Good Essays

    Identifying Nutrients
    • 955 Words
    • 4 Pages

    Identifying Nutrients

    Note: Disaccharides such as sucrose (table sugar) and lactose (milk sugar) are more complex than monosaccharides. The Benedict test does not detect disaccharides directly.…

    • 955 Words
    • 4 Pages
    Good Essays
    Read More
  • Satisfactory Essays

    Chemistry Lab Questions
    • 941 Words
    • 4 Pages

    Chemistry Lab Questions

    2. List whether each of the following substances was positive or negative for reducing sugar, as indicated by the Benedict's test. (6 points)…

    • 941 Words
    • 4 Pages
    Satisfactory Essays
    Read More
  • Good Essays

    Biochem
    • 1064 Words
    • 5 Pages

    Biochem

    | Mix 1ml of 5% glucose and 0.5ml of concentrated NaOH. Boil and note the change of color and odor produced. Do the same with 5% galactose, maltose, fructose, lactose, sucrose, glycogen and starch.…

    • 1064 Words
    • 5 Pages
    Good Essays
    Read More
  • Good Essays

    How to Live a Healthy Lifestyle
    • 599 Words
    • 3 Pages

    How to Live a Healthy Lifestyle

    Besides that , low sugar content is another plus . Sucrose is the bad kind of sugar . Glucose is the good kind of sugar . Both are sugar , so both are classified as sugar , on the label . For example , raisins that don’t have sugar added still have a lot of sugar , because it’s the good sugar , glucose .…

    • 599 Words
    • 3 Pages
    Good Essays
    Read More
  • Good Essays

    1.Find THE AMOUNT OF REDUCING SUGARS AND STARCH IN YELLOE AND GREEN BANANAS by Using the Benedict's test nad Iodine test. Why the Benedict's solution should be used in excess.
    • 1085 Words
    • 6 Pages

    1.Find THE AMOUNT OF REDUCING SUGARS AND STARCH IN YELLOE AND GREEN BANANAS by Using the Benedict's test nad Iodine test. Why the Benedict's solution should be used in excess.

    Reducing sugars include all monosaccharides (glucose) and some disaccharides (maltose). Benedict's solution contains copper sulphates. Reducing sugars reduce copper(2) ions present in the blue copper sulphate solution to insoluble red brown precipitates.…

    • 1085 Words
    • 6 Pages
    Good Essays
    Read More