Testing for carbohydrates - 3.4 - (2)

Question 1

What is the iodine test used to detect?

Answer 1

the presence of starch

Question 2

To carry out the iodine test, what do you do first?

Answer 2

you add the sample to a clean test tube

Question 3

What do you do after adding the sample to the test tube?

Answer 3

you then add a few drops of iodine dissolved in potassium iodide solution which is then mixed with the sample in the test tube

Question 4

What do you do after you mixed the iodine solution with the sample in the test tube?

Answer 4

the test tube is slightly shaken - if the solution changes from yellow/brown to purple/black, then the starch is present

Question 5

What happens if the iodine solution remains yellow/brown?

Answer 5

it is a negative result and starch is not present

Question 6

What can manufactured reagent test strips be used to test?

Answer 6

for the presence of reducing sugars, most commonly glucose

Question 7

With the use of a color-coded chart, what can be determined in reagent strips?

Answer 7

the concentration of the sugar

Question 8

What occurs in the testing for reagent strips?

Answer 8

1. the strip is quickly dipped into the test sample (blue end first)
2. you then look for the colour that the test strip turns into which is compared to a calibration card to estimate the concentration of the reducing sugars

Question 9

What are reagent test strips often used to test?

Answer 9

urine samples for diabetic patients