stored in the dark under argon at u2212 20 u00b0 c in a desiccator reagent b activator each 0 5 ml conical bottom cryogenic vial with a o ring seal cap contains 70 u03bcl of a 3 mm solution of tstu in dry dmf a stock solution is prepared by dissolving 3 31 mg 11 u03bcmoles of tstu in 5 ml of dry dmf under argon 70 u03bcl aliquots are pipetted into 0 5 ml conical bottom cryogenic vials closed and stored under argon at u2212 20 u00b0 c in a desiccator the kit is assembled by placing the vials containing reagent a and reagent b together with a desiccant bag inside a barrier film aluminium polyethylene pouch which is then heat sealed and stored at u2212 20 u00b0 c labelling of an antibody with a fluorescent or luminogenic dye using the kit of example 1 step 1 activated dye solution preparation fig2 a the kit is warmed to room temperature 50 u03bcl of reagent b activator solution are added to the vial containing reagent a the vial is capped and the dye dissolved by vortexing the mixture is kept in the dark at room temperature for 30 min fig2 a step 2 antibody solution preparation fig2 b each kit is designed to label 1 mg of igg mw 150 000 at 2 mg ml solution the antibody must be dissolved in an amine free buffer for antibody buffer solution to 450 ul of antibody diluted to 2 2 mg ml with pbs buffer 50 ul of 1 m ph 8 5 bicarbonate.