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Turbidimetria e nefelometria
Tecniche immunochimiche
quantitative per proteine
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104 to 1012 L/mol
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http://www.whfreeman.com/immunology/CH06/kuby06.htm
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When a diluted antigen solution is mixed with a corresponding antibody, the reaction between the
antigen and the antibody results in the formation of immune complexes. The solution becomes turbid.
Turbidimetry is based on an optical detection system that measure the turbidity, the concentration of
very small particles suspended in a solution. A light beam (incoming light, yellow arrow) sent trough a
solution is scattered depending on the degree of turbidity. A photodetector mesures the reduction in the
intensity of the light beam (transmitted light, blue arrows).
Since the transmitted light represents a decreasing signal (the more turbid the solution, the more light
will be absorbed), one normally refers to the ABSORBANCE this being an increasing quantity in
relation to the antigen concentration.
TURBIDIMETRY
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TURBIDIMETRY, IMMUNOTURBIDIMETRY: to
measure plasmatic and urinary proteins.
A complete line of CE marked last
generation tests: monoreagents, with stability
over 18 months, mostly without sample
predilution, short testing time, easy to automate.
Kits are available in standard bottles as well as in
Hitachi compatible bottles or upon customer
need.
Controls and calibrators complete this very
special line.
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Nephelometry
Analytical methods which depend on the measurement of the
intensity of scattered light emanating from an illuminated volume of
an aerosol. The ratio of scattered intensity to illuminating intensity iscompared with a standard of known properties.
1990, 62, 2202
IUPAC Compendium of Chemical Terminology 2nd Edition (1997)
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Rayleigh scattering (named afterLord Rayleigh) is the scattering oflight by particles much smaller
than the wavelength of the light. It occurs when light travels in transparent solids and liquids, but is
most prominently seen in gases. Rayleigh scattering of sunlight from particles in the atmosphere is
one reason light from the sky is blue.
The amount of Rayleigh scattering that occurs to a beam of light is dependent upon the size of the
particles and the wavelength of the light; in particular, the scattering coefficient, and hence the
intensity of the scattered light, varies inversely with the fourth power of the wavelength, a relationknown as the Rayleigh law. Scattering from particles larger than about a tenth of the illuminating
wavelength is handled by Mie theory.
The intensity Iof light scattered by a single small particle from a beam of light of wavelength and
intensity I0 is given by:
where Ris the distance to the particle, is the scattering angle, n is the refractive index of the particle,
and d is the diameter of the particle.
http://en.wikipedia.org/wiki/Lord_Rayleighhttp://en.wikipedia.org/wiki/Scatteringhttp://en.wikipedia.org/wiki/Lighthttp://en.wikipedia.org/wiki/Wavelengthhttp://en.wikipedia.org/wiki/Diffuse_sky_radiationhttp://en.wikipedia.org/wiki/Bluehttp://en.wikipedia.org/w/index.php?title=Scattering_coefficient&action=edithttp://en.wikipedia.org/wiki/Mie_theoryhttp://en.wikipedia.org/wiki/Refractive_indexhttp://en.wikipedia.org/wiki/Refractive_indexhttp://en.wikipedia.org/wiki/Mie_theoryhttp://en.wikipedia.org/w/index.php?title=Scattering_coefficient&action=edithttp://en.wikipedia.org/wiki/Bluehttp://en.wikipedia.org/wiki/Diffuse_sky_radiationhttp://en.wikipedia.org/wiki/Wavelengthhttp://en.wikipedia.org/wiki/Lighthttp://en.wikipedia.org/wiki/Scatteringhttp://en.wikipedia.org/wiki/Lord_Rayleigh7/27/2019 06_Immunoturbidimetria e Nefelometria
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FilterTrak 660 Laser Nephelometer Optical Configuration
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The BN ProSpec, the system of choice for
customers performing routine and specialty Plasma
Protein assays in medium throughput laboratories in
more than 50 countries worldwide has achieved a
new milestone. Dade Behring is pleased to announce
the placement of the 1000th BN ProSpec system.
The customer centered development process of the
BN ProSpec; system contributed significantly to
such wide acceptance and has been recently
recognized with the achievement of the 2003
International Project Management Award (IPMA).
This process allows our customers to be involved in
the development of system features.
Antigen excess security through optimized reaction conditions and pre-reaction protocols
Broad continouosly extended assay menu
Calibration of various assays in parallel using multi-analyte standards
Excellent assay precision and recovery of controls
Flexible combination of various types of sample tubes on any one segment
Full barcode identification of samples, controls, standards and reagents
Fully automated sample processing including customized re-measurements
More than 60 assay protocols allow determinations in serum, plasma, urine and CSF
Patient-oriented sample processing
Refrigerated on-board storage of controls and reagents
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Clinical Chemistry and Laboratory Medicine
Volume 39, Issue 11 (2001)
Sren Blirup-Jensen
Protein Standardization III: Method Optimization. Basic Principles for Quantitative Determination ofHuman Serum Proteins on Automated Instruments Based on Turbidimetry or Nephelometry
Abstract
Quantitative protein determinations in routine laboratories are today most often carried out using
automated instruments. However, slight variations in the assay principle, in the programming of the
instrument or in the reagents may lead to different results. This has led to the prerequisite of method
optimization and standardization. The basic principles of turbidimetry and nephelometry are discussed.
The different reading principles are illustrated and investigated. Various problems are identified and asuggestion is made for an integrated, fast and convenient test system for the determination of a
number of different proteins on the same instrument.
An optimized test system for turbidimetry and nephelometry should comprise high-quality antibodies,
calibrators, controls, and buffers and a protocol with detailed parameter settings in order to program
the instrument correctly. A good user program takes full advantage of the optimal reading principles for
the different instruments. This implies - for all suitable instruments -sample preincubation followed byreal sample blanking, which automatically corrects for initial turbidity in the sample. Likewise it is
recommended to measure the reagent blank, which represents any turbidity caused by the antibody
itself. By correcting all signals with these two blank values the best possible signal is obtained for the
specific analyte. An optimized test system should preferably offer a wide measuring range combined
with a wide security range, which for the user means few re-runs and maximum security against
antigen excess. A non-linear calibration curve based on six standards is obtained using a suitable
mathematical fitting model, which normally is part of the instrument software.
http://www.degruyter.de/journals/cclm/cclm39_11.htmlhttp://www.degruyter.de/journals/cclm/cclm39_11.html