Patent ID: 7544019

Claim:
A powder injection method for use with a powder injection microchip, the powder injection microchip comprising: a gas supply inlet for supplying gas; control means for controlling the supply of gas via the gas supply inlet; an outlet; a channel in fluid connection with the gas supply inlet and the outlet; a powder inlet in fluid connection with the channel, receiving an open first end of a powder reservoir, the powder reservoir having an opening at or near to a second end of the powder reservoir to allow egress of gas from the powder reservoir at a point distal to the first end of the powder reservoir; the method comprising the steps of: (i) supplying gas via the gas supply inlet to the channel and the powder inlet at a velocity sufficient to cause fluidisation of powder at the powder inlet; (ii) reducing the supply of gas to cause powder to pass from the powder inlet and to collect in a region of the channel adjacent a point where the powder inlet connects with the channel; and (iii) repeating steps (i) and (ii) a plurality of times, subsequent initialisation of step (i) causing the powder collected in the channel to be moved by the gas towards the outlet.