ROTOR HAVING SAMPLE HOLDING MEANS

1405694 Photometry sample holders UNITED STATES ATOMIC ENERGY COMMISSION 25 June 1973 [2 Aug 1972] 30108/73 Heading G2J A photometric analyzer of the multistation, rotary type has a rotor I comprising a circular array of loading cavities 7 within a circular array of sample analysis cuvettes 8, each cavity 7 being in radial alignment with a cuvette 8 and separated therefrom by a sloping barrier 12 to prevent transfer of liquid from 7 to 8 when the rotor 1 is static but permitting centrifugal transfer. Barrier 12 has a passageway 17 to one side at the top to assist mixing. A drain passageway 9 communicates with the radial extremity of each cuvette 8 and a central dynamic loading and distribution chamber 15 is provided which adjoins the radially inner edges of the loading cavities 7 and has a serrated periphery to cause equal distribution. The cavities 7 and cuvettes 8 may be formed in a PTFE disc 5 held between transparent plates 3, 4 in a steel body 2. In use, samples e.g. of blood are loaded via opening 19 in upper plate 4 or by using a transfer disc. The samples are then centrifugrally transferred to the cuvettes 8 to which access is afforded by recesses 13 in plate 4. The particulates of the samples are thus spread in a thin layer over the outer wall of cuvettes 8 and may be mixed with a diluent stream. After another centrifugal separation, the overlaying liquid may be removed by applying vacuum to drainline 9 or aperture 19 may be sealed and gas pressure applied to the central chamber. Optical Details: Agglomeration is measured by observing rate of sedimentation of resuspended particles using usual photometric techniques. Two radially spaced slit sources may be used to measure the time for the sedimenting boundary to pass from one radius to another. Agglomeration, lysis, fluorescence and radio-activity can be observed with appropriate detectors while supernatant liquid properties such as fluorescence, radio-activity and light absorbency can also be observed.