Patent GB-1523619-A (GB)
Title: Method and apparatus for liquid sample analysis
IPC: G01N33/48
Filed: 1975-12-29
Abstract: 1523619 Liquid sample analysis TECHNICON INSTRUMENTS CORP 29 Dec 1975 [29 May 1975] 53023/75 Heading G1B A sample source 10 has a turn-table 12 and probe 14 for immersion in liquid samples, e.g. blood serum, contained in holders 18 and 20 on the turn-table. The sampler has a wash receptacle 22 containing solution in which probe 14 is immersed between successive samples. When probe 14 leaves the sample liquid or wash solution air is aspirated into the probe to form an immiscible fluid segment in the stream in probe 14 on its reimmersion into the other liquid, producing a segmented liquid stream, whose segments are bounded by a pair of immiscible fluid segments. The probe 14 has a movable support 16 to enable movement between successive samples and to the wash solution between successive samples. The outlet end portion of probe 14 has a T connection, one outlet being coupled to the inlet end of a compressible pump tube 24 extending through a peristaltic pump 26 for flow through of a segmented stream. A tube 28 extends through pump 26 and has an inlet to reagent source 30. Downstream from pump 26, the outlet of tube 24 is coupled to tube 28. Pump tube 32, has an inlet end exposed to ambient air, extends through the pump and has an outlet coupled to tube 28 downstream of the pump and upstream of the coupling of tube 24 to tube 28. Downstream in tube 28 there is a mixing coil 34, heating bath 36 and photometric flowcell 38. A stream of reagent from source 30 flows in the  tube 28 by action of pump 26 and is segmented by gas from tube 32. The segmented sample stream in tube 24 is added to the segmented reagent stream in tube 28. Segments of sample are segmented by gas supplied in the last mentioned reagent stream. Sample and reagent are mixed in coil 34 and flow from the coil to bath 36 where reagent and sample react resulting in an optical density change. The reaction product flows from bath 36 via tube 28 to flowcell 38 where successive reaction products are photometrically analyzed. The above channel for the analysis of e.g. blood  serum sample for their albumin content is designated Channel 1 and is one of a plurality of channels for analyzing constituents of the samples. The other outlet from probe 14 is coupled to the inlet of tube 40 in which a division of the segmented sample stream from the probe flows. Any desired number of channels can branch off tube 40 e.g. channel 12 which has pump tubes 42, 44 and 46 extending through a continuously operated pump 48. The inlet of tube 42 is coupled to the outlet of 40 and the inlet of tube 44 is disposed in a source 50 of a different liquid reagent. Tube 44 has a coil 52, heating bath 54 and a flowcell 56. Compressible tubes 70 and 72 have outlets coupled to tubes 28 and 44 and have inlets disposed in sources of pilot fluids e.g. water. The analysis requirements of a sample are read by control device 82 prior to one incremental indexing movement of the turn-table 12 to the position of the sample holder 18. The position of the sample holder 18 is the sample offtake position. The signal from control device 82 is directed to programmer 84. The programmer, on command from the control 82, energizes valves 58, 60, 78, 80 and pumps 62, and 64. When constituents of a sample are to be analyzed in Channel 1 and Channel 12, valves 58 and 60 are open, valves 78 and 80 are closed and 62  and 64 are deenergized under the influence of control device 82. If the device 82 has transmitted a signal to the programmer 84 to discontinue the supply of reagent to Channel 1 while continuing the supply of reagent to Channel 12 for the sample in the holder 18, the constituent of that sample, e.g. glucose, is analyzed as described in Channel 12, while the programmer 84 is operative, in timed or phased relation to entry and mixture of the previous sample with reagent in tube 28, to close valve 58 and open valve 78. This results in discontinuance of the supply of reagent from the source 30 in tube 28 past the valve 58 and the commencement of the flow of the pilot fluid from the source 74 past the valve 78 and along tube 28 past the junctions of tubes 32 and 24. The pilot fluid is segmented by a gas from tube 32 and this stream, together with the addition of the stream supplied by tube 24 which comprises the sample from holder 18, displaces the preceding samples downstream in tube 28 through the mixing coil 34, heating bath 36 and flowcell 38 and to waste at the same flow-rate.