Abstract: An apparatus and a method of chemical analysis entail acquiring a chromatogram, median filtering the chromatogram to produce a model baseline, smoothing the model baseline to reduce noise, and subtracting the smoothed model baseline from the acquired chromatogram to produce a modified chromatogram having a substantially flat baseline.

Abstract: The present invention relates to a device having an optical fiber coupled to a high pressure containment vessel and a method for making the same. The high pressure containment vessel can be an optical fiber based flow cell for a chromatography system.

Abstract: The present invention is directed to the use of a light absorbing wall material to eliminate stray light paths in light-guiding structures, such as those used for HPLC absorbance detection. More specifically, the present invention relates to the use of carbon-doped Teflon® AF, or “black Teflon® AF,” for all or part of the walls of a light-guiding flowcell adapted for use in HPLC absorbance detection.

Abstract: The present invention is directed to the use of a light absorbing wall material to eliminate stray light paths in light-guiding structures, such as those used for HPLC absorbance detection. More specifically, the present invention relates to the use of carbon-doped Teflon® AF, or “black Teflon® AF,” for all or part of the walls of a light-guiding flowcell adapted for use in HPLC absorbance detection.

Abstract: The present invention is directed to the use of a light absorbing wall material to eliminate stray light paths in light-guiding structures, such as those used for HPLC absorbance detection. More specifically, the present invention relates to the use of carbon-doped Teflon® AF, or “black Teflon® AF,” for all or part of the walls of a light-guiding flowcell adapted for use in HPLC absorbance detection.

Abstract: The present invention relates to a device having an optical fiber coupled to a high pressure containment vessel and a method for making the same. The high pressure containment vessel can be an optical fiber based flow cell for a chromatography system.

Abstract: The present invention relates to apparatus and devices (11) for placing light with samples for analysis and method of making and using such apparatus and device.

Abstract: An apparatus and a method of chemical analysis entail acquiring a chromatogram, median filtering the chromatogram to produce a model baseline, smoothing the model baseline to reduce noise, and subtracting the smoothed model baseline from the acquired chromatogram to produce a modified chromatogram having a substantially flat baseline.

Abstract: A self scanning photodiode array allows low signal pixels to accumulate charge for multiples of predetermined exposure time t0 before being read. The pattern of exposures, the integers Mi where I runs from 1 to N the number of pixels in the array, is chosen such that the pixels of interest accumulate as much charge as possible without exceeding saturation.

Abstract: The present invention relates to apparatus and devices (11) for placing light with samples for analysis and method of making and using such apparatus and device.

Abstract: The present invention is directed to the use of a light absorbing wall material to eliminate stray light paths in light-guiding structures, such as those used for HPLC absorbance detection. More specifically, the present invention relates to the use of carbon-doped Teflon® AF, or “black Teflon® AF,” for all or part of the walls of a light-guiding flowcell adapted for use in HPLC absorbance detection.

Abstract: The present invention is directed to the use of a light absorbing wall material to eliminate stray light paths in light-guiding structures, such as those used for HPLC absorbance detection. More specifically, the present invention relates to the use of carbon-doped Teflon® AF, or “black Teflon® AF,” for all or part of the walls of a light-guiding flowcell adapted for use in HPLC absorbance detection.

Abstract: Excitation light of a selected wavelength from an excitation monochromator is directed along the long axis of a flow cell containing the sample to be analyzed, generating fluorescence. An emission monochromator is positioned at right angles to the plane of the excitation monochromator and receives the fluorescence from the flow cell utilizing optical components positioned such that the entrance slit of the emission monochromator is aligned with the long axis of the emission window. The intensity of the output from the flow cell is further maximized by positioning a retro-reflecting mirror at the end of the flow channel to effectively double the path-length of the excitation beam, and a reflecting surface on the side of the cell opposite the emission window to increase the collection efficiency and thereby increase the sensitivity of the detector.

Abstract: An optical scheme that substantially eliminates spherical aberration and coma, thereby substantially improving fluorescence excitation and collection efficiency. The optical scheme utilizes a laser beam focused by an optical component through the curved surface of a hyper-hemisphere. The hyper-hemisphere focuses the beam sharply at a known point while avoiding spherical aberration and coma. The optical scheme includes both a hyper-hemisphere and a hemisphere. Both the hyper-hemisphere and hemisphere have a substantially planar surface. The substantially planar surface of the hyper-hemisphere is optimally located so that a capillary or cell can be positioned at an internal aplanatic radius. This results in an aplanatic focus at the capillary or cell such that the spherical aberration and coma are zero. A single hyper-hemisphere having a substantially planar surface can be used, wherein the capillary is located at an aplanatic point on the substantially planar surface of the single hyper-hemisphere.

Abstract: A modular flow cell having a high optical throughput, a long optical path length and a small cross-section. The modular flow cell configuration includes remote ports or connections for liquid and light input, and liquid and light output. The flow cell includes a flow cell body having two ends, each with a respective end interface secured thereto. The flow cell is configured to formn a part of a modular flow cell assembly. The flow cell body includes a channel having a through-aperture with an inner surface. A light guiding material, e.g. a transparent fluoropolymer material having a refractive index less than the refractive index of common chromatography solvents, is disposed proximate to the channel to form a light guiding through-aperture in the flow cell body.

Abstract: An optical scheme that substantially eliminates spherical aberration and coma, thereby substantially improving fluorescence excitation and collection efficiency. The optical scheme utilizes a laser beam focused by an optical component through the curved surface of a hyper-hemisphere. The hyper-hemisphere focuses the beam sharply at a known point while avoiding spherical aberration and coma. The optical scheme includes both a hyper-hemisphere and a hemisphere. Both the hyper-hemisphere and hemisphere have a substantially planar surface. The substantially planar surface of the hyper-hemisphere is optimally located so that a capillary or cell can be positioned at an internal aplanatic radius. This results in an aplanatic focus at the capillary or cell such that the spherical aberration and coma are zero. A single hyper-hemisphere having a substantially planar surface can be used, wherein the capillary is located at an aplanatic point on the substantially planar surface of the single hyper-hemisphere.

Abstract: A flow cell for absorbance detection with at least two different optical path lengths. It increases the range of analyte concentrations which can be measured compared with a conventional single path flow cell. Light from the two paths is combined onto the same photodetector. Calibration with known samples allows analyte concentrations to be measured. The dual or multi-path length flow cell may be used in equipment designed for single path flow cells.

Abstract: A modular flow cell having a high optical throughput, a long optical path length and a small cross-section. The modular flow cell configuration includes remote ports or connections for liquid and light input, and liquid and light output. The flow cell includes a flow cell body having two ends, each with a respective end interface secured thereto. The flow cell is configured to form a part of a modular flow cell assembly. The flow cell body includes a channel having a through-aperture with an inner surface. A light guiding material, e.g. a transparent fluoropolymer material having a refractive index less than the refractive index of common chromatography solvents, is disposed proximate to the channel to form a light guiding through-aperture in the flow cell body.

Abstract: An optical scheme that substantially eliminates spherical aberration and coma, thereby substantially improving fluorescence excitation and collection efficiency. The optical scheme utilizes a laser beam focused by an optical component through the curved surface of a hyper-hemisphere. The hyper-hemisphere focuses the beam sharply at a known point while avoiding spherical aberration and coma. The optical scheme includes both a hyper-hemisphere and a hemisphere. Both the hyper-hemisphere and hemisphere have a substantially planar surface. The substantially planar surface of the hyper-hemisphere is optimally located so that a capillary or cell can be positioned at an internal aplanatic radius. This results in an aplanatic focus at the capillary or cell such that the spherical aberration and coma are zero. A single hyper-hemisphere having a substantially planar surface can be used, wherein the capillary is located at an aplanatic point on the substantially planar surface of the single hyper-hemisphere.

Abstract: A self scanning photodiode array allows low signal pixels to accumulate charge for multiples of predetermined exposure time t0 before being read. The pattern of exposures, the integers Mi where I runs from 1 to N the number of pixels in the array, is chosen such that the pixels of interest accumulate as much charge as possible without exceeding saturation.