A device for light-based analysis of a substance in a liquid sample comprises: an analysis cell for holding the liquid sample; wherein the analysis cell comprises a first wall portion for passing light generated by a light source into the analysis cell, and a second wall portion for passing light from the analysis cell to a light detector; and a plunger configured for movement along walls of the analysis cell for allowing entry of the liquid sample into the analysis cell and pushing the liquid sample out of the analysis cell; wherein at least one wiper is arranged on the plunger for cleaning the first and second wall portions during movement of the plunger.

A new technique which uses a pump-probe methodology to place a molecule into one or more excited rotational and/or vibrational states. By evaluating spectral changes due to at least one discrete frequency of pump photons a multi-dimensional characterization of the molecule's excited state energy level results. This multi-dimensional characterization typically involves evaluating the changes between excited and unexcited state measurements. The differential nature of the evaluation makes the technique self-referencing and solves problems common to many spectroscopic techniques. The multi-dimensionality of the technique provides high specificity and immunity to interferents. The preferred embodiments involve excitation by using photons suited to pumping the rotational states and evaluating the effects by probing the energy levels of one of more vibrational states. The technique is capable of detecting bulk and trace concentrations of a molecule in gas, liquid and solid phases, both in pure form and in the presence of other molecules.

A system for measuring a target gas via laser absorption spectroscopy in an open-air configuration, comprising a mid-infrared distributed feedback interband cascade laser (mid-IR DFB-ICL) having a wavelength selected to correspond with a spectral absorption line of the target gas and first electronic circuitry to control the laser temperature, current and modulation frequency. The mid-IR DFB-ICL is mounted to a heat sink. The system includes an optical component that projects a beam of the mid-IR DFB-ICL onto a distal backscattering directionally-reflective target and an optical receiver assembly that receives a fraction of the laser light that is backscattered from the directionally-reflective target and focuses the collected light onto an uncooled photodetector having a spectral bandwidth and optical configuration selected to optimize signal-to-noise response to received laser light. The optical receiver assembly comprises a primary mirror for receiving laser light backscattered from the directionally-reflective target and focusing the collected light onto the uncooled photodetector.

The present invention provides a method for measuring a content of a polycyclic aromatic hydrocarbon in a carbon black, comprising the following steps: extracting a carbon black to be measured using an organic solvent to obtain a sample to be tested; testing the sample to be tested by ultraviolet-visible spectrometer to obtain an absorbance; and using the absorbance and a calibration curve to obtain a content of a polycyclic aromatic hydrocarbon in the sample to be tested, wherein the calibration curve shows relationship between the absorbance of the polycyclic aromatic hydrocarbon and the content of the polycyclic aromatic hydrocarbon. The measurement method of the present invention benefits reduction of detection time.

A method for simultaneously measuring the activities of multiple kinds of enzymes in single channel through concimitantly monitoring multiple wavelength absorbances is claimed; based on linear additivity of absorbances and the isoabsorbance wavelengths of chromogenic substrates and their chromogenic products, both the principles for the combination of chromogenic substrates required for simultaneously measuring the activities of multiple kinds of enzymes in single channel through concimitantly monitoring multiple wavelength absorbances and an approach for data processing to eliminate the interference of the overlapped absorbances are developed, kinetic analysis of reaction curves via numerical integration eliminates the interference of all substrates and products and estimates the maximal reaction rates of the enzymes to be measured, giving the linear ranges and the limits of quantification for simultaneously measuring the activities of multiple kinds of enzymes in single channel comparable to those by separate assays; the present invention is applicable for simultaneously measuring the activities of multiple kinds of enzymes in biological samples, simultaneously measuring multiple components by enzyme-labeled immunoassays, screening simultaneously of inhibitors against multiple targets, for the practice in clinical biochemical analyses, clinical immunoassays, health laboratory analyses, the discovery of inhibitors, and the basical researches which need the present invention.

Disclosed is a method for measuring the absorbance of light of a substance in a solution in a measuring cell, said method comprising the steps of: transmitting a first light beam from a light source towards a beam splitter; dividing the first light beam into a signal light ray and a reference light ray by the beam splitter; modulating the signal light ray; modulating the reference light ray; providing the measuring cell such that the signal light ray passes through the measuring cell; detecting a signal in a detector, which signal is the combined signal intensity of the signal light ray and the reference light ray detected by the detector; performing synchronous detection of the detected signal in order to reconstruct the intensities of the signal light ray and the reference light ray from the combined signal detected by the detector, said synchronous detection being based on the modulation performed to the signal light ray and the reference light ray. Disclosed also is a measuring device for carrying out said method.

Disclosed is a sensor and method for detecting one or more gasses in a sample. The sensor includes two sample tube sections, which allow for a larger sample, and correspondingly, more accurate measurement. Having two sample tube sections increases the total length of the sample path. However, placing the sample tube sections in parallel allows for the performance of the sensor to be enhanced, but the footprint of the sensor to remain unchanged. Light pipe material may be used to transport the light between sample tube sections. Further, light pipe material may be used to move the IR lamp away from the first filter tube section, reducing problems in the thermopile by dissipating heat from the IR lamp away from the sample tube section.

A process for detecting at least one amine-type compound, the compound being chosen from hydrazine, ethanolamine, and morpholine, the process includes using a reagents composition including a mixture of 4-(dimethylamino)cinnamaldehyde and polystyrenesulfonic acid. Also, a kit for preparing the reagents composition, the reagents composition itself, and the uses of the reagents composition.

Optical spectroscopy based on adsorption of a sample on a surface of a mechanical resonator is provided. The sample is illuminated with light that is intensity modulated at or near the resonance frequency of a mode of the mechanical resonator. Thermal expansion caused by optical absorption at the sample effectively generates a force on the mechanical resonator that excites the resonant mode of the resonator. Thus a measurement of displacement or the like of the mechanical resonator (e.g., via the piezoelectric effect) provides the desired spectroscopic signal. Spectra can be obtained by sweeping a wavelength of the optical source or by using an optical dual-comb source having multiple emission wavelengths each intensity modulated at a different frequency.

A dilution of an oligonucleotide duplex is made. One aliquot of the dilution is added to a double-stranded nucleic acid (dsNA) melt at low concentration. A second aliquot of the dilution is added to a dsNA melt at high concentration. A third aliquot of the dilution is added to a reference cuvette containing only a first strand of the duplex. A fourth aliquot of the dilution is added to a reference cuvette containing only a second strand of the duplex. A first dsNA melt curve, a second dsNA melt curve, a first strand absorbance versus temperature curve, and a second strand absorbance versus temperature curve are produced. H and S are calculated for the first strand and the second strand from a fit to the first dsNA melt curve, the second dsNA melt curve, the first strand absorbance versus temperature curve, and the second strand absorbance versus temperature curve.