A system for detecting a specific substance or analyte of interest is provided that includes one or more sensing units and an instrument for analyzing the sensing units. Each sensing unit preferably includes a substrate, an attachment layer and at least one capture layer that includes a ligand layer. In one embodiment, the attachment layer is tripartite and includes a lower binding surface held to the substrate and an upper binding surface that holds the ligand layer, together with an insulating layer disposed between these two surfaces. The lower binding surface provides a durable and stable attachment to the substrate. The upper binding surface holds the ligand layer and does not jeopardize the integrity or viability thereof. The insulating layer prevents any unwanted interaction between the lower and upper binding surfaces. Each sensing unit is supported on a test piece received by the instrument. The instrument controllably positions the test piece using marks and/or codes on the test piece. The instrument measures a difference in mass in the sensing unit in connection with determining whether or not the analyte of interest is present. A light beam is used in making this measurement. In one embodiment, multiple reflections of the light beam on the same sensing unit are utilized to improve the sensitivity of the instrument. Mass enhancement techniques are also preferably utilized to effectively amplify the detected signal that is indicative of the analyte's presence. The system can also include a device for heating, humidifying and mixing materials of the sensing units, as well as preventing cross-contamination of the sensing units.

Sensing system for specific substance and molecule detection

A spectroscopic system for the analysis of small and very small quantities of substances makes use for the purposes of energy transfer of cone-shaped aperture changers (14, 15) which are arranged in the object zone (8) between the light source (L) and the sample (9) and, during absorption measurements, also between the sample (9) and the inlet slot (3) of a spectrometer (1). If the form used is a double cone, the aperture changers (14, 15) facilitate an oblique coupling in a capillary tube accepting the sample (9) which acts as a step-waveguide for the coupled radiation.

Spectroscopic systems for the analysis of small and very small quantities of substances

Method for specific substance and molecule detection

In a detection apparatus, a linearly polarized light beam polarized in a polarizer (62) is converted by being transmitted through a Pockels cell (60), driven by an alternative voltage, into an alternative linearly polarized light beam and a circularly polarized light beam, which is transmitted through a sample solution flowing through a flow cell (68). The transmitted light beam is separated into two polarized light components, and an intensity thereof is measured to obtain a signal proportional to an angle of rotation by the sample solution. A signal corresponding to an angle of rotation caused by an optical rotary power of the sample solution is obtained by subtracting the signal obtained during irradiation of the circularly polarized light from the signal obtained during irradiation of the linearly polarized light. The sample solution (18) is infused into an optical path of the flow cell (68) under a condition where mean velocity is 0.5 to 5 m/sec.

Method of detecting angle of optical rotation in solution having time-dependent concentration, detection apparatus therefor, and detector cell therefor

Changes in polarized light incident on a detection zone with a separation matrix are used to detect optically active molecules within the separation matrix. The separation and detection of the presence of optically active molecules within a detection zone in a separation matrix involves: a) loading a sample containing optically active molecules onto a separation matrix; b) applying a motive force to the sample to cause the sample to migrate through the separation matrix and to separate the sample into a plurality of subgroups of optically active molecules; c) directing an incident beam of polarized radiation to the detection zone of the separation matrix; d) processing the collected exiting beam with an optical component which discriminates between radiation having the same polarization as the incident beam and radiation having a different polarization from the incident beam; and e) measuring the intensity of the processed exiting beam, wherein a difference between the intensity of the processed exiting beam and a standard intensity obtained for the separation matrix in the absence of sample is indicative of the presence of an optically active molecule in the detection zone. Alternatively, an incident beam of alternately left and right circularly polarized radiation of the type generated using a Pockels cell of Ker cell can be used. When such radiation encounters an optically active substance which absorbs radiation of the incident wavelength, radiation of one polarization is preferentially absorbed. Differences in the intensity of the pulses of left and right circularly polarized radiation that has passed through the detection zone of the separation matrix indicate the presence of optically active species within the detection zone.

Method and apparatus for automated electrophoresis using light polarization detector

An optical amplifier for amplifying optical polarization state change effects comprises an arrangement for passing polarized light through a material a plurality of times such that changes in the polarization state of the polarized light from the respective passes of the light through the material are cumulative. The amplifier can be used in a method for detecting optical polarization state change effects wherein polarized light which is passed through the material is detected. The material may be a liquid sample from a high performance liquid chromatography system.

Richard F. Spanier

Papers

Optical amplifier and method for amplifying optical polarization state change effects