5 results about "Refractometry" patented technology

Methods and systems configured to measure content of a target substance in a fluid sample using a refractometer including a light source and a light sensor. A method includes: calibrating the refractometer by identifying a calibration pixel pattern of first pixels of the light sensor illuminated by light from the light source that has reflected off a sensing surface of a container including a reference fluid having a known reference density; identifying a blood pixel pattern of second pixels of the light sensor illuminated by light from the light source that has reflected off the sensing surface when the fluid sample is present in the container; identifying a pixel shift distance along the light sensor from the calibration pixel pattern to the fluid pixel pattern; and determining the content of the target substance in the fluid sample based on the pixel shift distance.

This invention belongs to the field of compound analysis and provides a method for detecting the content and isomer ratio of hydroxypropyltetrahydropyranotriol using high-performance liquid chromatography-differential refractive index (HPLC-DRI). The method includes the following steps: qualitative and quantitative analysis of prepared standard solutions and test solutions using HPLC-DRI. The method provided by this invention uses a simple and clean mobile phase with no impact on human health, simplifies sample pretreatment, has a low detection limit for hydroxypropyltetrahydropyranotriol, exhibits good linearity within the linear range, high correlation coefficient, high resolution of diastereomers, and good repeatability. It provides an effective detection method for ensuring the quality of hydroxypropyltetrahydropyranotriol and screening for superior grades.

Objective refraction error measuring apparatuses are known. Once the measurement is done, there is no known method for confirming if the measurements are correct. Disclosed is an apparatus wherein once the error is measured, the determined values of the error are used to set the characteristics of a tunable lens so as to correct the error in the vision of the subject. The objective error is measured again while the subject viewing through the tunable lens so set. Objective refraction error is again measured. If the error measured is now within predefined limits, the first measurement is deemed correct and the values are out put so that glasses with those values may be prescribed to the subject.

Disclosed is method for determining the concentration of constituents in a fluid, such as cutting fluids or HFC fluids, using refractometry by means of a laser of a measuring device that uses the transmitted light principle, comprises specifying a peak value for the laser light received by refraction on a photodiode line using a homogeneous fluid to be transilluminated, and keeping the peak value constant despite the occurrence of disturbances by adapting one or more of the duty cycle of the laser, the current intensity for the laser, and the sensitivity of the photodiode line.

A method and system is provided that measures plasma protein levels of whole blood while a plasma donor is connected to an apheresis machine. A refractometer associated with the apheresis machine is capable of receiving a portion of a disposable tubing set including an integrated cuvette and prism. The integrated cuvette of the disposable tubing set can be inserted into a receiving space of the refractometer associated with the apheresis machine such that the light source and the sensor are oriented relative to the prism and a sensing surface of the integrated cuvette in a precise alignment. Calibration of the refractometer is made using anticoagulant pumped through the disposable tubing set including the integrated cuvette and prism. Based on a light intensity associated with this calibration, whole blood is then measured to determine plasma protein levels and donor eligibility.