SYSTEM AND METHOD OF NEPHELOMETRIC DETERMINATION OF AN ANALYTE

摘要

A nephelometry system for an automatic analysis device may include a light source, a stop, and a photodetector on the one hand and a receptacle position on the other hand that are movable relative to one another in order to improve the measurement quality of a nephelometry system. The nephelometry system may determine a location of an interval I of recorded light intensity signals which only contains light intensity signals that emerge from a scattered portion of a light beam after passing through a measurement cell placed into the nephelometry system. Methods of nephelometric determination of an analyte are also provided, as are other aspects.

主权项

1. A method of nephelometric determination of an analyte in a sample, with the sample being situated in a measurement cell, the method comprising:
(a) placing the measurement cell into a nephelometry system comprising at least one optical unit, the optical unit comprising at least one light source for emitting a light beam, a stop for blocking the non-scattered portion of the light beam after passing through the measurement cell and a photodetector for receiving scattered portions of the light beam after passing through the measurement cell; (b) moving the measurement cell and/or moving the optical unit such that the light beam emitted by the light source passes through the measurement cell along a route; (c) recording the light intensity signals received by the photodetector along the route, along which the light beam emitted by the light source travels through the measurement cell; (d) determining the location of an interval I of the recorded light intensity signals which only contains light intensity signals that emerge from the scattered portion of the light beam after passing through the measurement cell, wherein the size of the interval I emerges from a defined number of light intensity signals and is a predetermined parameter for the employed nephelometry system; and (e) determining the analyte on the basis of a light intensity signal or on the basis of a mean value for a plurality of light intensity signals from the interval I of the recorded light intensity signals; wherein the location of the interval I of the recorded light intensity signals is established by the light intensity signals recorded along the route being evaluated as follows: forming the first and second derivative of the light intensity signals recorded along the route; determining a first position Ff along the route with the conditions f′(x)<0 and f″(x)=0; determining a second position Fs along the route with the conditions f′(x)>0 and f″(x)=0; determining a third position M along the route by applying the formula M=Ff+(Fs−Ff)/2; and positioning the interval I such that the position M forms the center of the interval I.