RP11-measuring conc. of glucose

Question 1

how can Benedict’s solution be used to measure the concentration of glucose in a solution

Answer 1

use a colorimeter to measure the absorbance of a series of solutions of known concentrations to create a calibration curve.
-compare the absorbance of an unknown sample to the calibration curve

Question 2

what is a serial dilution

Answer 2

a dilution where successive concentrations increase in a logarithmic fashion

Question 3

outline the procedure of this practical

Answer 3

-make a serial dilution of glucose, ranging from 0-10mmold dm-3
-place 2cm3 of unknown sample into each tube
-add 2cm3 of benedict’s solution to all test tubes
-place tubes in water bath at 90C for 4 mins
-zero the colorimeter using a cuvette with distilled water and set to red filter
-place known samples into cuvette and measure the absorbance of each using the colorimeter
-make a calibration curve
-measure the absorbance of the unknown samples using the colorimeter and determine its conc.

Question 4

what does a high glucose concentration in urine suggest

Answer 4

-may suggest diabetes
-lack of insulin leads to high glucose concentrations

Question 5

state the hazards and precautions of this practical

Answer 5

-Benedict’s solution, irritant, avoid skin contact, wear goggles
-hot water, burns, handle with care

Question 6

How can you increase the accuracy of the estimate of the unknown glucose solution

Answer 6

-increase the number of concentrations at smaller intervals for the calibration curve