Abstract: Microparticle-based analytical methods, systems and applications are provided. Specifically, the use of resonant resonant light scattering as an analytical method for determining either or both a particle's identity and the presence and optionally, the concentration of one or more particular target analytes is described. Applications of these microparticle-based methods in biological and chemical assays are also disclosed.

Abstract: A DNA sequencing system and method are described to detect the presence of radiant energy emitted from different excited reporter dye-labeled species (DNA fragments) following separation in time and/or space, and the identity of the species which emit radiant energy closely spaced in wavelength. Functions of the emitted energy are obtained which vary over the wavelengths of the closely spaced spectra in different senses and the functions ratioed, whereby the ratio is indicative of the identity of the DNA fragments. The emitting portion of the reporter-labeled DNA fragment is preferably one of a family of fluorescent dyes based on 9-carboxyethyl-6-hydroxy-3-oxo-3H-xanthene. These xanthene dyes are covalently attached to the DNA fragments through the carboxylic acid functionality, preferably via an amide linkage. The dyes may be protected by including an alkoxy group at the 9-position. A spacer may be inserted between the dye and the amine.

Abstract: A DNA sequencing system and method are described to detect the presence of radiant energy emitted from different excited reporter dye-labeled species (DNA fragments) following separation in time and/or space, and the identity of the species which emit radiant energy closely spaced in wavelength. Functions of the emitted energy are obtained which vary over the wavelengths of the closely spaced spectra in different senses and the functions ratioed, whereby the ratio is indicative of the identity of the DNA fragments.The emitting portion of the reporter-labeled DNA fragment is preferably one of a family of fluorescent dyes based on 9-carboxyethyl-6-hydroxy-3-oxo-3H-xanthene. These xanthene dyes are covalently attached to the DNA fragments through the carboxylic acid functionality, preferably via an amide linkage. The dyes may be protected by including an alkoxy group at the 9-position. A spacer may be inserted between the dye and the amine.

Abstract: A DNA sequencing system and method are described to detect the presence of radiant energy emitted from different excited reporter dye-labeled species (DNA fragments) following separation in time and/or space, and the identity of the species which emit radiant energy closely spaced in wavelength. Functions of the emitted energy are obtained which vary over the wavelengths of the closely spaced spectra in different senses and the functions ratioed, whereby the ratio is indicative of the identity of the DNA fragments.The emitting portion of the reporter-labeled DNA fragment is preferably one of a family of fluorescent dyes based on 9-carboxyethyl-6-hydroxy-3-oxo-3 H-xanthene. These xanthene dyes are covalently attached to the DNA fragments through the carboxylic acid functionality, preferably via an amide linkage. The dyes may be protected by including an alkoxy group at the 9-position. A spacer may be inserted between the dye and the amine.

Abstract: The method of this invention obtains the underlying peak shapes of two signal spectrums whose ratios are representative of different species. The underlying peak shapes are fitted to the signal spectrums in a way that yield accurate ratios. The ratios are accurate even when the location of the peaks are not precisely known.

Abstract: A system for detecting the radiant energy emitted from different closely spaced species includes two detectors each having a large entrance angle for receiving the radiant energy, and wavelength selective filters between the detector and species, the transmission vs. wavelength characteristics being complementary, and means for ratioing functions of the detector outputs, the ratio being indicative of the identity of the species.

Abstract: An accurate method of determining by plasma chromatography the concentration of an ionizable gaseous or volatile chemical species A in air or another gaseous medium. Small, known increments of species A plus, optionally, another calibrant species are introduced in turn into the plasma chromatograph together with the unknown sample; and the respective changes of the amplitude or area of a characteristic ion peak of species A in the unknown sample are measured. The second, optical calibrant, which is different from species A, must have similar kinetic characteristics but a different ion mobility from the ion formed by A. By means of this technique, inaccurate readings caused by background concentration variations are significantly reduced.