Scattering signal

Turbidimetry and Nephelometry. In contrast to classical absorbance methods, immunoassay reactions frequently involve agglutination in which the optical scatter signal of the agglutinated particles is measured by turbidimetric or nephelometric means. The principles of light scattering as it relates to analytical methods is discussed in reference 6. 

The relation is sketched in Fig. 7.3. From the shape of the curve we anticipate that good scattering signals are obtained, if the thickness of the transmitted sample is in the range 0.5/jU < t < 3/fJ,. 

Examining the scenario with M receivers and one common emitter there is a significant practical limitation when attempting to implement the previous methodology. It was assumed in that analysis that the scattered signals must be processed jointly. This is easier to achieve... 

Determination of Cytotoxicity by Measuring Light Scatter Signals. 315... 

Set up the flow cytometer with fluorescence detectors turned off and the acquisition terminator set for TIME, so that a constant volume from each sample will be analyzed. A time interval (e.g., 1 min) that will be sufficient for the acquisition of approximately 10,000 events in the control samples should be used. Acquire light scatter signals (ESC and SSC) for each sample, vortexing the cell suspensions briefly but vigorously before introducing each sample into the flow cytometer. 

The light scatter assay may be used to determine absolute numbers of viable cells if flow cytometry data from cell suspensions of known concentration are used to construct a standard curve. For that purpose, cell concentrations should be determined in a series of graded, standard cell suspensions with the use of a Coulter counter. A plot of those standard concentrations versus the number of events (Hght scatter signals) acquired during a specified acquisition interval in the flow cytometer may then be used to interpolate cell concentrations for test samples that have been assayed by the light scatter procedure. 

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