Photometric device

#The present invention relates generally to photometric devices, such as those used to analyze blood, and more particularly to photometric devices utilizing ultraviolet light and a multi-assay plate having ninety-six (96) vessels arranged as eight (8) rows by twelve (12) columns, typically referred to as a microplate. U.S. Pat. Nos. 4,591,550; 4,968,148; and 5,112,134 concern photometric devices, and the teachings thereof are expressly incorporated herein by reference.

#A variety of techniques and devices are commercially available for the detection and measurement of substances present in fluid or other translucent samples by determining the light transmissivity of the sample. These can be broadly categorized into devices which measure the optical properties of one sample or a small number of samples essentially simultaneously and those which measure a large number of samples essentially simultaneously.

#Photometric devices that simultaneously perform individual assays on a plurality of liquid or other translucent samples use a multi-assay plate which contains an array of vessels, such as eight rows by twelve columns (8.times.12), four rows by six columns (4.times.6), two rows by three columns (2.times.3), five rows by eight columns (5.times.8). Typically, the vessels of the multi-assay plate are spaced at nine (9) millimeter centers, have a volume of approximately four hundred (400) milliliters, and have a height of approximately one (1) centimeter. The multi-assay plate is made of material, such as polystyrene or polyethylene, that is optically transparent at the wavelengths of interest.

#Preferred embodiments of the present invention are described, in detail, with reference to the drawing wherein:

#FIG. 1 is a block diagram illustrating the major components of the photometric device;

#FIG. 2 is a schematic of the optical system of the preferred embodiment of the present invention shown in FIG. 1;

#Referring to FIG. 1, a preferred embodiment of the present invention is shown as a photometric device or measurement system, generally designated 10, for testing fluid samples contained in vessels in a multi-assay plate 12. The multi-assay plate 12 is a conventional microplate, including a standard array of vessels arranged in eight (8) rows by twelve (12) columns (8.times.12). The photometric measurement system 10 includes and operates, in a conventional manner, under the direction and control of an acquisition and control processor means 14, a central processing unit means 15, and a user interface computer 30, as further described herein, which cooperatively define processor means 25 for initialization, set-up, data acquisition, analysis and display.

#A light source means 22 emits a band of wavelengths of light having a first wavelength range of approximately 200 nanometers to approximately 1100 nanometers. A desired, essentially monochromatic light, with a wavelength in the range of 250 to 750 nanometers, is selected by a wavelength selection means 23 and delivered through an optical fiber 58 to a light distribution means 24. The light distribution means 24 delivers eight (8) channels of test light (representatively shown in FIG. 1) sequentially to the samples in a column of eight (8) vessels of the multi-assay plate 12 and delivers one channel of reference light, used to substantially eliminate errors in measurement due to the variations over time in light amplitude emitted from the light source means 22. A photodetector means 26 detects and measures both the test light that has passed through the vessels and the reference light. The acquisition and control processor means 14, coupled to the photodetector means 26, provides electrical output signals in a conventional manner, in accordance with the reference light and the test lights.

#The photometric measurement system 10 includes a chamber means 16, having an open and closed state and an entry/exit door 111, for housing the multi-assay plate 12. A plate carrier means 20 receives, peripherally supports and carries the multi-assay plate 12 from a loading position remote from the chamber means 16 to a measurement station therein, sequentially advancing each column of vessels to the measurement station. The chamber means 16 and plate carrier means 20 operate in a conventional manner.