Method for counting living cells of microbes and apparatus therefor

Claim 1

A method for counting living cells of microbes in a fluid sample continuously while flowing the sample comprising adding to the sample a reagent capable of reacting with one or more substances intrinsic of the living cell to form an accumulative fluorescent product within the living cells, passing the so treated sample through a photometric detection cell continuously while irradiating the flowing sample with a light having a wave length adapted to induce excitation of the fluorescent product accumulated within each of the living cells to cause emission of corresponding fluorescence from each of the living cells as each individual luminous point and counting up the individual luminous points appearing within an detection area of the detection cell in a certain time interval.

Claim 3

A method as claimed in either of Claims 1 and 2, wherein the sample is irradiated by the exciting light from a side portion of the photometric detection cell.

Claim 4

A method as claimed in either one of Claims 1 to 3, wherein the reagent employed is one or more derivatives of fluorescein.

Claim 8

An apparatus for counting living cells of microbes in a fluid sample continuously while flowing the sample, which comprises a system for supplying at a predetermined rate to the flow line of the sample a reagent capable of reacting with one or more substances intrinsic of the living cell to form an accumulative fluorescent product within the living cells; a reactor inserted in said flow line of the sample and being provided for said reaction of the reagent with the cell-intrinsic substance in the living cells; and a photometric detection system arranged subsequent to said reactor for detecting fluorescence emitted from the fluorescent product in each of the living cells floating in the flowing sample, said photometric detection system comprising a photometric detection cell having a flat throttled portion to be served for the optical inspection of the sample flowing therethrough defining internally a rectangular thin flow section extending laterally to the flow of the sample, an irradiation means having a light source for irradiating the sample by an exciting light from the light source having a wave length adapted to induce excitation of the fluorescent product accumulated in each of the living cells to cause emission of corresponding fluorescence from each living cell as each individual luminous point, an optoelectronic unit for detecting each of the luminous points with a means for converting the incidental fluorescence into an electric pulse, and an electronic unit for counting the electric pulses and controlling the operation of the apparatus, said optoelectronic unit including an optical inlet aperture in a form of a slit extending parallel to said portion of the photometric detection cell over the entire width of said thin flow section thereof for receiving the fluorescence from each of the individual luminous points in the flowing sample, photosensors disposed in a row parallel to said inlet slit and connected each to each corresponding input terminal of said electronic unit and a condenser lens disposed so as to focus each image of the luminous point onto said row of the photosensors.