Effect of Ozone on Vegetables (Pesticide Removal)

One sample of leafy vegetable "choy sum" was sprayed with Lindane and Profenofos, two types of commercially used pesticide. The "choy sum" was then left overnight and divided into two portions and treated as follows for the analysis of pesticide residue :-

A) Unwashed
B) Soaked in tap water with ozone treatment for 30 minutes.
On analysis of the pesticide removal efficiency test by High Performance Liquid Chromatography (HPLC) and Gas Chromatography (GC), the following results were obtained: -

- - - Lindane, mg/kg Profenofos, mg/kg
A) Unwashed sample ... 50 5000
B) Ozone treated sample ... 1.02 124

The results showed that both pesticide residues were reduced to low level after ozone treatment.*The ozone treatment was carried out in 3 litres of tap water.