Abstract: Homogeneous assays for determining quantitatively the extent of a specific binding reaction can be carried out effectively on very dilute solutions using measurements of fluorescence if a fluorescence measurement scheme that is capable of rejecting short-lived background fluorescence is employed and if the fluorescent group being measured has the following properties: a. the group being measured must be a rare earth metal chelate complex combination; b. the chelate must be water-soluble; c. the complex combination must also be stable in extremely dilute aqueous solutions, that is, the measured chelate must have at least one ligand having a metal-to-ligand binding constant of at least about 1013M−1 or greater and it must have a fluorescent emission that is long-lived compared to the longest decay lifetime of ambient substances and have a half life of from 0.01 to 50 msec.

Abstract: Homogeneous assays for determining quantitatively the extent of a specific binding reaction can be carried out effectively on very dilute solutions using measurements of fluorescence if a fluorescence measurement scheme that is capable of rejecting short-lived background fluorescence is employed and if the fluorescent group being measured has the following properties: a. the group being measured must be a rare earth metal chelate complex combination; b. the chelate must be water-soluble; c. the complex combination must also be stable in extremely dilute aqueous solutions, that is, the measured chelate must have at least one ligand having a metal-to-ligand binding constant of at least about 10.sup.13 M.sup.-1 or greater and it must have a fluorescent emission that is long-lived compared to the longest decay lifetime of ambient substances and have a half life of from 0.01 to 50 msec.

Abstract: Species-linked diamine triacetic acids of the formula ##STR1## wherein T is an organic species containing at least one amine, hydroxyl, or thiol functional group, L is the residue of at least one of those functional groups and R is a two or more atom long covalent bridge, are disclosed. Methods for their preparation, for the preparation of metal chelates from them and for the use of the chelates are also disclosed. In a preferred embodiment, the metal ions employed in the formation of the chelates are rare earth metal ions capable of forming fluorescent chelates which can in turn be employed in fluoroassay techniques.

Abstract: A new reporter mechanism for biospecific reactions is disclosed. This mechanism involves interligand metal ion transfer in which a metal ion is directly transferred from one chelate complex to another following the occurance of the biospecific reaction. The second chelate complex is separate from and detectably different than the first chelate complex. This invention can take the form of methods of chemical analysis and kits for conducting such methods. In preferred embodiments of this invention the detectable difference is a difference in fluorescence, such as an increase or decrease which occurs as a result of the formation of the second chelate. In further preferred embodiments the difference in fluorescence is detected using fluorescent background rejection methods.

Abstract: Species-linked diamine triacetic acids of the formula ##STR1## wherein T is an organic species containing at least one amine, hydroxyl, or thio functional group, L is the residue of at least one of those functional groups and R is a two or more atom long covalent bridge, are disclosed. Methods for their preparation, for the preparation of metal chelates from them and for the use of the chelates are also disclosed. In a preferred embodiment, the metal ions employed in the formation of the chelates are rare earth metal ions capable of forming fluorescent chelates which can in turn be employed in fluoroassay techniques.

Abstract: Species-linked diamine triacetic acids of the formula ##STR1## wherein T is an organic species containing at least one amine, hydroxyl, or thiol functional group, L is the residue of at least one of those functional groups and R is a two or more atom long covalent bridge, are disclosed. Methods for their preparation, for the preparation of metal chelates from them and for the use of the chelates are also disclosed. In a preferred embodiment, the metal ions employed in the formation of the chelates are rare earth metal ions capable of forming fluorescent chelates which can in turn be employed in fluoroassay techniques.

Abstract: A new family of fluorescent antibodies (FAB) and a method for their synthesis is disclosed for use in an apparatus and method wherein the effects of background fluorescence are virtually eliminated from fluorescence measurements. The novel fluorescent antibodies consist of antibodies conjugated with rare-earth chelates which have unique fluorescent properties. These fluorescent antibodies are useful because when excited with short pulses of light, they exhibit fluorescent decay times which are much longer than typical background fluorescence at room temperature and with a spectral width far narrower than typical background fluorescence.

Abstract: A longitudinally excited gas laser having a laser tube in contact with a readily fabricated mass of material which conducts and dissipates heat generated in the tube, serves as part of a low inductance electrical transmission line for the laser tube discharge and aligns sections of the tube for ease of assembly and operation.

Abstract: The output power of any laser is optimized by providing an output mirror with a transmission which varies as a function of position on the mirror and transmitted wavelength. The transmission which corresponds to the optimum output for a given laser wavelength is chosen by monitoring laser output and moving the output mirror in at least one direction essentially perpendicular to the laser beam axis while maintaining the orientation of its reflecting surface perpendicular to the laser beam axis, and locating the mirror position corresponding to optimum laser output.

Abstract: A method and apparatus for background correction in photoluminescent analysis of a selected photoluminescent target substance with a relatively narrow emission spectrum in the presence of ambient substances with a combined photoluminescent spectrum which is relatively broad. The photoluminescence of the target substance is sampled and measured in a narrow wavelength band corresponding to the principal emission spectrum of the target. A second sample of photoluminescence is measured in one or more wavelength bands adjacent to the first wavelength band, but excluding substantially all of the photoluminescence of the target substance, and transmitting only ambient photoluminescence. The second measurement is converted into an amount which would occur if ambient photoluminescence had been sampled in the first wavelength band and then the converted amount is subtracted from the first measured amount, thereby correcting the first measured amount for photoluminescence derived from ambient substances.

Abstract: A method is disclosed whereby the molecules of a chemical substance to be measured, referred to as target molecules, are combined with fluorescent molecules having a relatively long fluorescent decay lifetime. These tagged target molecules are excited with an intense pulse of ultraviolet or visible radiation, and a detection system is gated on only after background fluorescence has substantially decayed, but while the fluorescent tag attached to the target molecules is still actively decaying. The amount of fluorescent tag emission which is measured is indicative of the target molecule content of the sample. An apparatus for improved fluorescent spectrofluorometry includes a pulsed excitation source and a gating means connected to a detection system for gating the detection system on after tagged target molecules have been excited and competing background fluorescence has substantially decayed, but before tagged target molecules have substantially decayed.