How to test for vitamin C at home

Detecting vitamin C in fruits and vegetables

Safe­ty pre­cau­tions

Wear pro­tec­tive gloves, a mask, and safe­ty glass­es. Per­form this ex­per­i­ment in a well-ven­ti­lat­ed area.

Reagents and equip­ment

  • 3% aque­ous so­lu­tion of io­dine in potas­si­um io­dide;
  • a sheet of wa­ter­col­or pa­per;
  • a kiwi;
  • an or­ange;
  • a bell pep­per;
  • a knife;
  • a cut­ting board;
  • a cot­ton ball;
  • a dis­pos­able plas­tic cup.

Step-by-step in­struc­tions

Use the cot­ton ball to ap­ply the 3% aque­ous so­lu­tion of io­dine in potas­si­um io­dide to the sheet of pa­per. Slice the or­ange, kiwi, and bell pep­per. Ar­range the slices on the pa­per, with the fresh-cut sides fac­ing down­wards. In 15 min­utes, watch as the pa­per dis­col­ors right un­der the fruit slices.

Process de­scrip­tion

Many fruits and veg­eta­bles con­tain ascor­bic acid, also known as vi­ta­min C. It plays a key func­tion in bi­o­log­i­cal pro­cess­es in the body as a strong an­tiox­i­dant. An­tiox­i­dants are com­pounds that ab­sorb var­i­ous free rad­i­cals (ox­i­diz­ing agents that can cause mu­ta­tions and de­struc­tion in cells). Io­dine can be used to test veg­eta­bles and fruits for ascor­bic acid con­tent. Io­dine is an ox­i­dant, so when it re­acts with ascor­bic acid, it is re­duced to col­or­less io­dide ions.

C₆H₈O₆ + I₂ → C₆H₆O₆ + 2HI

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