Patent ID: 7936459

Claim:
An apparatus adapted to obtain a profile of a stationary density gradient sample, the apparatus comprising: a fluorescent light source; a probe comprising a first probe needle actuatable to extend into a tube containing the gradient, said probe being in communication with the light source and comprising a first light-transmitting means to receive light from the light source and transmit light having an excitation wavelength into the gradient as the probe needle extends into the gradient, and a second light-transmitting means to transmit received light to a signal-producing means, wherein the first light transmitting means comprises a transmitting fibre optic bundle and a first reflection means and the second light-transmitting means comprises a second reflection means and a receiving fibre optic bundle, said light being transmitted by the transmitting fibre optic bundle and reflected by the first reflection means into the gradient at an angle of about 90° to the first probe needle, wherein the light strikes particles in the gradient and causes the particles to emit light at an emission wavelength which is received by said second light-transmitting means and is reflected by said second reflection means to said receiving fibre optic bundle and transmitted by said receiving fibre optic bundle to a signal-producing means; and a signal-producing means adapted to receive light from the second light-transmitting means, said signal-producing means comprising a photodetector to translate the light into a recordable signal to produce a profile of the gradient.