Nephelometry


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nephelometry

[‚nef·ə′läm·ə·trē]
(optics)
The study of suspensoids using the techniques of light scattering.
The study of the scattering properties of small samples of air and its suspensoids.

Nephelometry

 

the methods used to measure the intensity of scattered visible or ultraviolet light in a given medium in order to determine the concentration, size, and shape of disperse particles in disperse systems. The nature of the scattering of light—that is, the reflection of light by illuminated suspended particles (often called the Tyndall effect)—varies according to the ratio of the size of the disperse particles to the wavelength of the incident light. If the maximum size of suspended particles is less than 0.1 the wavelength, the light scattering is symmetrical in space and is known as Rayleigh scattering. Larger particles produce light scattering that is more intense but irregular, with the scattering being greater in the direction of the incident light beam.

The theory of light scattering is used in measuring both the intensity of scattered light (nephelometry) and the intensity of the transmitted light (turbidimetry), which is reduced because of the scattering. The concentration of the disperse phase, which is used in chemical analysis, can be determined after a calibration has been made by measuring suspensions with known concentrations. The measurement of light-scattering intensity in solutions at various concentrations makes it possible to determine the molecular weights of polymers. The angular dependence of light scattering for large particles and the degree of polarization of the scattered light provide information on the shape of the particles or macromolecules. Nephelometry is also used in studying emulsions and other colloidal systems and in meteorology, marine physics, and some biological investigations.

REFERENCES

Landsberg, G. S. Optika, 4th ed. Moscow, 1957. (Obshchii kurs fiziki, vol. 3.)
Shifrin, K. S. Rasseianie sveta v mutnoi srede. Moscow-Leningrad, 1951.
Tager, A. A. Fiziko-khimiia polimerov. Moscow, 1963.
Voiutskii, S. S. Kurs kolloidnoi khimii. Moscow, 1964.

IU. A. KLIACHKO

References in periodicals archive ?
Serum and salivary IgA was analyzed using nephelometry (Agappe Diagnostics, Kerala, India).
HS-CRP levels were measured using nephelometry, a latex Particle Enhanced Turbidimetric Immunoassay technique (PETIA) (NA Latex CRP Kit, Dade Behring, UK).
Zinc level was assayed by nephelometry using the HITACHI LABOSPECT 008 (Hitachi, Japan); HbA1c was assayed by high-performance liquid chromatography method using Premier Hb9210 (PRIMUS, USA); C-peptide was assayed by electrochemiluminescence method using Cobas e411 (Roche, Switzerland); SCr was assayed by enzymic method using Beckman Coulter AU5800 (Beckman Coulter, USA); TC and TG were assayed by enzymic method using Beckman Coulter AU5800 (Beckman Coulter, USA); HDL-C and LDL-C were all assayed by direct method using Beckman Coulter AU5800 (Beckman Coulter); urine ACR was assayed by picric acid method using Cobas c311 (Roche).
Leakage of urine microalbumin was carried out by nephelometry, so that 24-h urine was collected and measured every four weeks for 12 weeks and 30300 mg microalbumin was considered as microalbuminuria (17,18).
Samples were cooled for 45 minutes, inspected visually for precipitate formation, and the turbidity measured by nephelometry, expressed as nephelometric turbidity units (NTU).
Serum levels of rheumatoid factor (normal value < 20 IU/mL) were determined by nephelometry (Immage immunochemistry system, Beckman-Coulter, Brea, CA, USA).
The complete blood count was measured with a laser-based flow cytometric impedance device (Mindray BC-6800, Nanshan, Shenzhen, China 2012), and the CRP was measured with a Beckman Coulter Immage nephelometry device.
The ultrasensitive C-reactive protein (CRP) was assessed by Nephelometry (Nephelometer Beckman Coulter, Image model with laboratory reagents CCRP Image, Fullerton, CA, USA).
The probiotic bacterial density was calculated with nephelometry and aimed to obtain a probiotic:candida cell ratio of 1:1.
Ruckert, "Monitoring of microbial growth curves by laser nephelometry," GOR-TOKYO-, vol.