vitamin c core practical
measuring the content of vitamin C in fruit juice
independent - types of fruit juice
dependent - volume of juice required to decolourise the 1cm^3
of DCPIP
variables to be controlled - concentration or DCPIP solution
(1%), same end point colour - until the blue colour of DCPIP just
about disappears, temperature
100mg per 100ml (1mg/ ml)
method:
• pipette 1cm blue DCPIP into test tube using burette (or
accurate pipette)
• add 1% vitamin C solution drop by drop. Shake tube gently
after each drop.
• continue until the blue colour just disappears. Record
volume of solution needed to decolourise the DCPIP.
• repeat further 2 times and calculate mean result.
• repeat procedure with different fruit juices.
• calculations: 1cm° of 1% vitamin C solution contains 10mg
Vitamin C, therefore mass in 1cm" = 10mg x volume of 1%
vitamin C to decolourise 1cm® of DCPIP.
• mass in sample = mass of vitamin C to decolourise 1cm^3
DCPIP volume of sample
measuring the content of vitamin C in fruit juice
independent - types of fruit juice
dependent - volume of juice required to decolourise the 1cm^3
of DCPIP
variables to be controlled - concentration or DCPIP solution
(1%), same end point colour - until the blue colour of DCPIP just
about disappears, temperature
100mg per 100ml (1mg/ ml)
method:
• pipette 1cm blue DCPIP into test tube using burette (or
accurate pipette)
• add 1% vitamin C solution drop by drop. Shake tube gently
after each drop.
• continue until the blue colour just disappears. Record
volume of solution needed to decolourise the DCPIP.
• repeat further 2 times and calculate mean result.
• repeat procedure with different fruit juices.
• calculations: 1cm° of 1% vitamin C solution contains 10mg
Vitamin C, therefore mass in 1cm" = 10mg x volume of 1%
vitamin C to decolourise 1cm® of DCPIP.
• mass in sample = mass of vitamin C to decolourise 1cm^3
DCPIP volume of sample
