Abstract: An apparatus is described in which an optical fiber is mounted within a fiber optic holder which includes the non-rotating shaft of a linear actuator. The fiber holder may be held captive in order to restrain the fiber holder and, consequently, the fiber mounted therein, from rotating during operation of the linear actuator, thereby resulting in linear travel with minimal rotational effects and minimal change in optical alignment of the fiber during travel. In addition, an optical path length sensor in conjunction with an optimized absorbance method of operation is utilized herein to provide micron precision of the displacement between respective receiving and transmission fibers so as to enable precise absorbance measurements from about 0.005 up to about 2.0 Absorbance Units for any given path length.

Abstract: A dual-mode method and apparatus of selectively measuring samples in either a vessel or as a surface tension retained sample held between two opposing pedestals is introduced. In either configuration, such modes further contain optical paths from a source system through a small-volume or large-volume sample to a spectrometer based system. Such a system enables a user to measure samples with absorbances ranging from about 0.005 up to about 2.0 Absorbance Units for any given wavelength.

Abstract: The invention is an installment for making multi-channel spectroscopic measurements on a plurality of nanodrop samples held by surface tension between opposing optical fibers wherein a single fiber is scanned across a linear spaced array of receiving, detecting fibers.

Abstract: A photometer is provided with modular lighting units wherein each lighting unit includes one or more light emitters. A user may select a desired lighting unit and install it within a photometer base unit, and thereafter activate one or more of the emitters (which may emit light of different wavelengths) to illuminate a specimen. The light provided by the specimen in response can then be captured at a detector, and analyzed to provide an indication of the specimen's characteristics. Different lighting units may optionally include one or more input light adapters (filters or polarizers which modify the light provided by the emitter(s) to the specimen), and/or one or more output light adapters (filters or polarizers which modify the light provided by the specimen to the detector). Users may therefore select lighting units with emitters and light adapters which are particularly suited for detection/analysis of particular specimens and/or components therein.

Abstract: Apparatus and method for measuring the fluorescence of nanodrop liquid samples is described in which the sample is held by surface tension between two anvil surfaces. Each anvil surface has an embedded optical fiber with its end finished flush with the surface in the containment area wetted by the sample with the fiber in line. Sample excitation is provided from the side of the sample remote from the containment area. By selection of the fiber transmission numeric aperture the impact of exciting and ambient light on the measurement is minimized. A method of virtual filtering is taught in which any ambient or exciting light that does impinge on the measuring sensor is corrected by subtracting a scaled representation of the source from the measurement. The method and apparatus is capable of detecting 1 femptomole of sodium fluorescein in 1 microliter of TE buffer.