an appropriate solution catechins u2014 gallic acid theaflavins u2014 pg instant tm tea powder and a standard agreement check performed the operating methods for the catechin and theaflavin analysis are outlined below column nucleosil tm 15 cm 3 mm ods 0 46 cm diameter detector 280 nm the solvent system for this protocol was a 2 acetic acid in acetonitrile and b 2 acetic acid aqueous the pump was set at 1 5 a isocratic for 10 minutes 2 5 18 a gradient 1 for 30 minutes 3 18 a isocratic 10 minutes 4 50 a gradient 0 for 5 minutes and 5 5 a isocratic for 15 minutes column hypersil tm 10 cm 3 mm ods 0 46 cm diameter detector 280 nm the solvent system for this protocol was a 2 acetic acid in acetonitrile and b 2 acetic acid aqueous the pump was set for 20 a running isocratically for 12 minutes catechins in freeze dried leaf samples from the control see fig4 freeze dried leaf from the co 2 treated sample see fig4 it can be seen from fig4 and 5 that if tea leaf is plucked and then u2018 fermented u2019 then the level of catechins present will decrease slowly approximately 15 in 8 hours with no resultant formation of theaflavins however when the leaf is treated with carbon dioxide the rate of catechin loss in the leaf is faster approximately 80 in 8 hours and theaflavins are formed in the leaf comparison of fermentation timecourse of co 2 treated and ctc treated leaf 75 g of sri lankan leaf was treated and fermented as described in example 2 further to this 300 g of leaf was passed through a ctc machine three times before.