Abstract: In a system for measuring variations in thickness of an optical etalon, a light source and a diffraction grating are mounted on a base structure with an axle. A lever arm is affixed to the axle, and a micrometer is held in contact with the lever arm. The grating directs a into an optical path a wavelength of radiation dependent on orientation of the grating. The etalon is supported in the optical path to effect a fringe pattern representing variations in thickness of in the etalon. The orientation is varied with the micrometer so as to vary the wavelength to the etalon and thereby positioning of the fringe pattern across the etalon which is viewed through a microscope. The micrometer measures the variation of orientation and thereby variation in thickness across the interference element.

Abstract: In a spectrophotometer, each of a plurality of source optical fibers is selectively receptive of source radiation and carries the radiation to a corresponding selected liquid sample cell. A corresponding return optical fiber returns transmitted radiation from the sample to a polychromator. For selecting a sample, a switching member holds exposed ends of the optical fibers on a circle coaxial with an axle for rotating to selected positions. Respective optical trains in the instrument direct radiation into and out of the selected pair of fibers. The diameter of a source aperture, the spacing of the aperture from the radiation source, and the source area define a source etendue. The optical fibers have a fiber etendue substantially the same as the source etendue.

Abstract: The present invention refers to a dual-beam polychromator comprising a reflecting dispersion grating, a first entrance slit for a first ray bundle, a second entrance slit for a second ray bundle and first and second detector devices respectively used for simultaneously detecting the spectra of the first and second ray bundles diffracted at the dispersion grating. Dual-beam polychromators which are known according to the prior art and which have their respective entrance slits arranged directly adjacent the detector devices of the other channel cause substantial structural difficulties with regard to the mechanical provision of the respective components.

Abstract: An atomic emission spectrometer includes an induction coupled plasma generator and a detector system for detecting the radiation relative to spectral wavelength. A first mirror is on the longitudinal axis of the generator to receive axial radiation therefrom. A second mirror is disposed laterally from the generator so as to reflect radial radiation therefrom parallel to the longitudinal axis toward a third mirror disposed laterally from the longitudinal axis. The third mirror passes the radiation to a fourth mirror positioned adjacent to the axial radiation without interfering therewith so as to reflect the radial radiation to the first mirror. The first mirror is rotated to a first orientation to reflect the axial radiation into the detector system, or to a second orientation to reflect the radial radiation into the detector system.

Abstract: An optical switch includes a primary optical fiber terminating in a primary window, and a plurality of secondary optical fibers each terminating in a secondary window facing in the same direction as and spaced laterally from the primary window. A primary lens on a primary axis has a focal point positioned on the axis at the central window. Each of a plurality of secondary lenses has an axis and a focal point positioned on such axis at a secondary window. The secondary axes are parallel to and equidistant from the primary axis. A retroreflector is spaced from the lenses oppositely from each window and has an optical axis centered parallel to the primary axis midway between the primary axis and any of the secondary fibers. A stepper motor rotates the retroreflector about the primary axis to each of a plurality of selected positions to provide optical switching for light transmission between the primary fiber and any selected secondary fiber.

Abstract: A kit and method for reduction of primer-independent background signals in a DNA replication/detection assay, particularly in a direct in situ PCR amplification/detection assay, for a target DNA sequence in DNA sample, comprising pretreating the DNA sample, containing the target DNA sequence to be replicated/amplified and assayed, with DNA polymerase and one or more dideoxynucleoside triphosphates prior to conducting the replication/amplification steps.

Abstract: The bead source for the thermionic detector of a gas chromatograph is heated by the secondary winding of a transformer having a center-tapped primary and operating in the push-pull configuration. The voltage drop across the bead is compared with a preselected reference voltage and an error signal is generated. The error signal is used to control the output of a pulse width modulation control which supplies the transformer primary winding.

Abstract: The present invention is directed to a nebulizer for use in an atomic absorption system which includes a capillary assembly having a capillary holder having an internal axial passage therethrough, a sapphire capillary tip mounted on one end of the capillary holder and the other end of the holder being connected to a sample liquid source through a capillary gland nut assembly. A venturi member is provided which has an inlet portion, a throat portion and an exiting bell shaped portion. A body assembly has one end connected to the venturi member. The capillary assembly is mounted on the body assembly for axial movement so that the capillary holder partially enters the venturi inlet portion and the capillary tip enters the venturi throat. Compressed oxidant is supplied to the venturi member in the vicinity of the capillary tip so as to suck sample liquid from the capillary tip to form a mixture of fine liquid mist and gas which is discharged through the exiting bell shaped portion.

Abstract: This invention is directed to a plastic holder assembly for loosely holding a plurality of microtiter sample tubes, which includes a tray having a plurality of holes for receiving the tubes and having opposite vertical end walls, each of which have two spaced vertically extending slots and a horizontally extending recess between the slots; a retainer releasably nestable in the tray having a corresponding plurality of holes and having opposite vertical end walls corresponding to the end walls of the tray; a U-shaped handle extending horizontally outwardly from each of the opposite retainer end walls, each handle having two legs which slide into the tray slots respectively when the retainer is nested in the tray; a tab projecting horizontally outwardly from each of the retainer end walls between each of the two legs which snap into the tray end wall recesses respectively when the retainer is nested in the tray, the retainer having an elongated slot parallel and directly adjacent each of the end walls, whereby i

Abstract: In FT-DIRLD (Dynamic Infra Red Linear Dichroism) apparatus partly represented in FIG. 1, units 100-105, responding to interferometer output IB (indicated elsewhere), cause unit 106 to yield an interferogram combining static and dynamic dichroism interferograms. Reference signals respectively in phase and quadrature with cyclic sample strain are derived from rheometer 102. At each OPD point of predetermined uninterrupted scans, controller 108 routes simultaneously a data point of the combined interferogram and the reference signals to respective channels of multiplexer 107. A microprocessor (shown elsewhere) subsequently performs a best-fit-to-an ellipse sorting of the data and for each OPD derives: A) the value of the interferogram unaffected by sample modulation; B) the corresponding in phase term; and C) the corresponding in quadrature term; furthermore, from the A, B,C data-point series it generates the interferogram of each series and transforms it into a spectrum.

Abstract: An Echelle polychromator 50 has disposed upstream thereof a pre-monochromator 14 comprising a prism 20. The linear dispersion of the pre-monochromator 14 is variable by varying the angular dispersion of the prism 20. A particular spectral position and the close vicinity thereof are analyzed by an Echelle grating 54 with high resolution. Care must be taken that, on the one hand, the detector array 66 of the Echelle polychromator 50 is fully exploited in response to the central wavelength respectively observed and that, on the other hand, interfering orders are kept away from the Echelle polychromator 50. The linear dispersion of the pre-monochromator is variable for this purpose.

Abstract: A method and apparatus are provided for correction of spectra for stray radiation in a spectrometric instrument, involving a sequence of steps as follows. Spectral patterns are obtained with the instrument initially for monochromatic radiation at a plurality of selected calibration wavelengths. By computer program, the peak profile at the calibration wavelength in each pattern is replaced with a substitute based on the remaining pattern. The resulting data are interpolated to effect values denoted "stray proportions" for the ordered wavelengths of the instrument. Spectral data at each ordered wavelength are obtained with the instrument for a sample, and multiplied in the computer program by stray proportions for corresponding wavelengths to effect further sets of values denoted "stray portions" that are identified to the ordered wavelengths. Each set is identified to one of the wavelength increments of the instrument across the spectral range.

Abstract: In a spectrophotometer, each of a plurality of source optical fibers is selectively receptive of source radiation and carries the radiation to a corresponding selected liquid sample cell. A corresponding return optical fiber returns transmitted radiation from the sample to a polychromator. For selecting a sample, a switching member holds exposed ends of the optical fibers on a circle coaxial with an axle for rotating to selected positions. Respective optical trains in the instrument direct radiation into and out of the selected pair of fibers. The diameter of a source aperture, the spacing of the aperture from the radiation source, and the source area define a source etendue. The optical fibers have a fiber etendue substantially the same as the source etendue.

Abstract: Spectral bands are grouped for data acquisition in a spectrophotometer with a charge-coupled detector having a plurality of pixels. Preliminary data is generated on time-integrated radiation to the pixels for a sample. Maximum permitted exposure times for the pixels are calculated from the data and a predetermined maximum exposure. The maximum times are grouped so that for each group the ratio of the highest to the lowest maximum times is less than 100. A group run time is established for each group nominally less than the lowest maximum time in the group. Subgroups are created and ordered so that accumulated readout times for the pixels are less than wait times established to prevent readout contamination from subsequent charge buildup. The spectrophotometer is further operated on the sample for the run time of each group and subgroup to generate spectral data.

Abstract: A complete in situ PCR system for amplification of nucleic acids contained in a prepared cell or tissue sample. The containment system for the PCR sample comprises a glass microscope slide, a specimen sample containing the target nucleic acid sequence mounted on the slide, a flexible plastic cover over the sample, and a retaining assembly fastened to the slide and to the cover to retain and seal a reaction mixture against the sample during thermal cycling. The retaining assembly includes a rigid ring on a rim portion of the cover, a cross beam having spaced parallel rails joined by opposite flat ends, and a pair of clips which are pressed over the ends and opposite sides of the slide to fasten the cross beam and cover to the slide.

Abstract: A plunger homing mechanism for use in automated chromatography. A plunger cap holder holds the plunger cap of a syringe within a housing. The housing is biased with an isolation spring within a casing. The casing is raised and lowered to move the syringe plunger held within the housing. When the casing is lowered and the plunger hits bottom, the relative movement between the housing and the casing is detected by a sensor. The casing movement is then caused to stop. This permits the detection of a home or reference position for the accurate and precise withdrawal of a sample to be analyzed. Additionally, damage to the syringe from over driving the plunger rod is prevented.

Abstract: A spherical sample cell (FIG. 4A) bears an external inwardly specular laye defining a hollow imaging mirror 11D and an optical aperture 11E. The mirror acts as an integrator of both the exciting radiation for irradiating the sample and the resulting excited radiation to be analysed, the former entering and the latter exiting through the aperture 11E. Optical integration resulting from multiple internal reflections provides multifold increase in excited radiation compared with bare cells, which is of particular advantage in Raman spectrophotometry. Alternatively, the mirror may be provided in two complementary halves in a two-part cell-holder, in which case any conventional sample cell that fits within the mirror may be used. Spectrophotometers adapted for use with the sample cell or the cell holder as well as methods based on them are described.

Abstract: The flow-injection system includes a microwave oven having a flow-through reactor having a flow-through conduit located in windings around a conduit carrier for absorbing microwaves. The windings extend through the radiation cavity of the microwave oven only with a part of their length and transversely to the radiation direction. The microwave oven includes programmable adjusting means for the heating power and the heating period. Thus, in connection with a reduction flow-through reactor and an atomic absorption spectrometer, a determination of hydride formers and mercury in a material sample is possible, independently of the valence state.

Abstract: In order to provide a linear calibration graph when analysing samples by atomic absorption spectroscopy, a maximum absorbance value is determined conventionally for a given analyte. The individual absorbance values of a sample containing an unknown amount of the analyte are processed as a function of the maximum absorbance value in accordance with the function ##EQU1## The thus obtained corrected individual absorbance values are integrated with respect to time to yield a corrected time-integrated absorbance value which is proportional to the amount of analyte present in the sample. This amount is determined using a calibration factor obtained from the analogously corrected time-integrated absorbance value of a calibration sample containing a known amount of the analyte.

Abstract: A method for determining concentration of an analyte in a sample includes generating a spectrum of a selected analyte and interferents, generating a spectrum of an unknown sample, computing first and second derivatives of the sample spectrum, deriving a matrix model that includes the analyte spectrum and the derivatives, and applying the matrix model to the sample spectrum so as to yield a parameter representing concentration of the selected analyte in the unknown sample. Multiple linear least squares regression is utilized to fit the model and calculate the parameter.