Nephelometry

Turbidimetry and nephelometry are two related techniques in which an incident source of radiation is elastically scattered by a suspension of colloidal particles. In turbidimetry, the detector is placed in line with the radiation source, and the... 

Determining Concentration by Nephelometry In nephelometry, the relationship between the intensity of scattered radiation, hy and the concentration (% w/v) of scattering particles is given as... 

Description of Method. Adding BaC to an acidified sample precipitates S04 a BaS04. The concentration of S04 may be determined either by turbidimetry or nephelometry using an incident source of radiation of 420 nm. External standards containing known concentrations of S04 are used to standardize the method. 

Spectroscopic measurements may also involve the scattering of light by a particulate form of the analyte, fn turbidimetry, the decrease in the radiation s transmittance through the sample is measured and related to the analyte s concentration through Beer s law. fn nephelometry we measure the intensity of scattered radiation, which varies linearly with the analyte s concentration. 

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. 

AMW = absorption, multiple wavelength per test N = nephelometry T = turbidimetry P = potential and R = reflectance. 

Several sulfate determinations in model solutions and urine samples were earried out. The results are of suffieiently good reprodueibility (within 10% rel.) and are in agreement with gravimetry and nephelometry data. This faet allows us to reeommend this method for express-determination of sulfate in urine. 

How can human observers, optical measurements along a line of sight, and point measurements by nephelometry provide conflicting information about visual air quality in the same location ... 

Seligson s group (95) has published a similar turbidimetric procedure but used nephelometry to measure continuously the effect of lipase on the light scattering of an olive oil emulsion. The instrumentation and approach is the same as that described above for the nephelometric determination of amylase. The method according to the authors is fast and precise with good specificity and sensitivity. The short time required for analysis makes it suitable for emergency use. The technical simplicity permits this method to be easily automated, and it appears to be the lipase method of choice. 

Bevan, C. D., Uoyd, R. S. A high-throughput screening method for the determination of aqueous drug solubility using laser nephelometry in microtiter plates. Anal. Chem. 2000, 72,1781-1787. 

Light scattering (nephelometry) was used as a detection system for gly-cosaminoglycans from urine, eluted from a DEAE Sephadex (Pharmacia Biotechnology Uppsala, Sweden) A-25 column.68 This technique has been more recently applied to protein characterization.69 Interferometry was used for analysis of dextran eluted from a size exclusion column.70 One of the problems of electrochemical detection is that it is relatively insensitive to polymers. Because many of the materials discussed below (DNA, proteins, and polysaccharides) are polymeric, a brief mention of some alternative... 

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