EXP 5: Special Test for Saccharides

Nitro-Chromic Acid Test

What is the test shown?

1. Nitric Acid (HNO3)

2. Potassium Chromate (K2CrO4)

What are the reagents of this test?

Oxidation

What is the process involved in this test?

Nitro-Chromic Acid Test

What is the test due to the presence of a -CHOH group?

Presence of -CHOH group/oxidation of primary alcohol

What is a positive result for the Nitro-Chromic Acid test due to?

Faint Blue

What color indicates a positive reaction for the Nitro-Chromic Acid Test?

Yeast, Sugar, Phosphate Buffer

What are the reagents of alcohol fermentation?

6.4-6.8

What is the pH of phosphate buffer?

Sucrose, Glucose, Galactose

What are the sugars used in Alcoholic Fermentation?

Bubbles

What is indicative of a positive reaction of Alcoholic Fermentation?

Carbon Dioxide (CO2)

What are the bubbles of Alcoholic Fermentation due to?

Mucic Acid Test/Galactaric Acid Test

What is the test shown?

Galactose

What is the sugar tested?

Oxidation

What is the process involved?

Mucic Acid

Identify the substance.

Mucic Acid Test

What is the test for identifying galactose?

Galactose

What sugar does the Mucic Acid test identify?

Oxidation of Galactose

What is Mucic Acid formed by?

5% Galactose & Conc HNO3

What are the reagents of the Mucic Acid Test?

White Crystals

What is the result of the Mucic Acid Test?

True

True or False: Mucic Acid is an isomer of saccharide acid.

1. Cupric Sulfate (CuSO4)

2. Potassium Hydroxide (KOH)

3. Rochelle Salt

What are the components of Fehling’s solution?

1. 0.01 M Glucose

2. 0.01 M Fructose

3. 0.01 M Sucrose

4. 0.7% Starch

5. Water

What are the sugars and control tested in Fehling’s test?

1. Glucose

2. Fructose

What sugars test positive in Fehling’s Test?

Red Precipitate

What is a positive reaction in Fehling’s test?

Reduction of the copper ions (and oxidation of either the Aldehyde or Ketone Group)

What is the precipitate in Fehling’s test due to?

Sucrose & Starch because they are non-reducing sugars.

What sugars test negative for Fehling’s test and why?

Benedict’s Test

What is the test shown?

Test for glucose in urine

What is this test clinically used for?

Benedict’s Solution (Cupric Sulfate (CuSO4), Sodium Carbonate (Na2CO3), Sodium Citrate)

What is the reagent of this test?

1. 0.1 M Glucose

2. 0.01 M Glucose

3. 0.002 M Glucose

What sugar is in each test tube (left to right)

Benedict’s Test

What is the qualitative test for glucose in urine?

1. Cupric Sulfate (CuSO4)

2. Sodium Carbonate (Na2CO3)

3. Sodium Citrate

What is Benedict’s solution composed of?

1. 0.1 M Glucose

2. 0.01 M Glucose

3. 0.002 M Glucose

What is the order of most to least reaction in Benedict’s test?

Barfoed’s Test

What is the test to detect reducing monosaccharides, thus differentiating monosaccharides form disaccharides?

Cupric Acetate (Cu(CH3COO)2) in Acetic Acid (CH3COOH)

What is in Barfoed’s Solution?

1. 0.01 M Glucose

2. 0.01 M Fructose

3. 0.01 M Lactose

4. 0.01 M Sucrose

5. 0.03 M Glucose

6. 0.03 M Lactose

7. 0.03 M Sucrose

What are the sugars tested in Barfoed’s Test?

1. 0.03 M Glucose

2. 0.01 M Fructose

3. 0.01 M Glucose

4. NR - 0.03 M Sucrose

5. NR - 0.01 M Sucrose

6. NR - 0.01 M Lactose

7. NR - 0.03 M Lactose

What is the order to fastest to slowest speed of reduction in BARFOED’s Test?

False (Fructose reacts faster than glucose in BARFOED’s Test)

True or False: With the same concentration, glucose reacts faster than fructose in BARFOED’s test.

Cuprous Oxide (Cu2O)

What is the product of reduction in Barfoed’s Test?

Iodine Test

What is the test for polysaccharides?

Iodine Test

What is the test shown?

1. Starch

2. Dextrin

What are the sugars in the test tube (left to right)?

1. Starch: Colorless

2. Dextrin: Yellow

When heated, what color does each sugar become (left to right)?

Iodine (I2) Solution

What is the reagent added?

Starch & Dextrin

What are the sugars tested in the Iodine test?

Starch: When warmed becomes colorless but when cooled returns to original color, blue-black

Dextrin: When warmed becomes yellow but when cooled returns to original color, black-violet

What occurs to the sugars in Iodine Test when heated then cooled?

C6H8N2

Formula of phenylhydrazine

1. 5% Glucose

2. 5% Fructose

3. 5% Maltose

4. 5% Lactose

5. 5% Sucrose

What are the sugars tested in the Phenylhydrazine reaction?

Phenylhydrazine Reaction

What is the test useful in identifying sugars with free aldehyde or ketone group?

2 phenylhydrazine hydrochloride : 3 sodium acetate

How is phenylhydrazine prepared?

1. Glucosazone

2. Fructosazone

3. Maltosazone

4. Lactosazone

5. NO Osazone Crystals

What is the product of the following in the Phenylhydrazine reaction:

1. Glucose

2. Fructose

3. Maltose

4. Lactose

5. Sucrose

A. Barfoed’s (since Barfoed’s solution contains Acetic Acid)

Which reaction occurs in an acidic environment?

A. Barfoed’s

B. Fehling’s

B. Fehling’s (since Fehling’s solution contains Sodium Hydroxide)

Which reaction occurs in an basic environment?

A. Barfoed’s

B. Fehling’s

True (In Benedict’s Test, the higher the glucose concentration, the higher the amount of red precipitate)

True or False: The degree of colors change depends on the amount of reducing sugar present.

Osazone Test

What is another name for the phenylhydrazine reaction?

1. Fructose (Fructosazone): 2 minutes

2. Glucose (Glucosazone): 4-5 minutes

3. Maltose (Maltosazone): Soluble in hot water

4. Lactose (Lactosazone): Soluble in hot water

5. Sucrose without Hydrolysis: N/A (No crystals form unless Sucrose is hydrolyzed)

Time or Solubility for each osazone formation?

Glucosazone; Needle-Like

Identify name and describe the osazone.

Fructosazone; Needle-like

Identify name and describe the osazone.

Maltosazone; sunflower-shaped

Identify name and describe the osazone.

Lactosazone; cotton-ball like

Identify name and describe the osazone.

N/A; No osazone has formed

Identify name and describe the osazone.