Finding concentration of glucose

Question 1

What 3 ways can be used to better identify substances?

Answer 1

-colorimetry
-biosensors
-chromatography

Question 2

What is a colorimeter?

Answer 2

-device that measures how much light a substance absorbs
-the more concentrated the colour of the solution, the higher the absorbance, the lower the glucose concentration

Question 3

What must you do before you can test the unknown substance?

Answer 3

-make a serial dilution of known concentrations
-plot a calibration curve

Question 4

How do you make 5 serial dilutions with a factor of 2?

Answer 4

-line up 5 test tubes in rack
-add 10cm3 of known concentration of glucose solution to test tube 1
-add 5cm3 of distilled water to other 4 tubes
-pipette 5cm3 from test tube 1 into tube 2 and mix (halved concentration)
-repeat process 3 more times

Question 5

How do you make calibration curve?

Answer 5

-do Benedict’s test on each solution
-remove precipitate via centrifuging
-use colorimeter with red filter to measure absorbance in each tube
-use results to make calibration curve

Question 6

What’s on axis of calibration curve?

Answer 6

Y- absorbance
X- glucose conc

Question 7

What happens after you have made the calibration curve?

Answer 7

do Benedict’s test and colorimetry on unknown solution and compare to calibration curve

Question 8

What do biosensors do?

Answer 8

devise that uses a biological chemical to detect a chemical in a solution

Question 9

How do biosensors work?

Answer 9

-biological molecule produces signal which is converted into electrical signal by a transducer
-electrical signal is processed and can be used to work out other info