Turbidimetria e nefelometria

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     1  Turbidimetria e nefelometria Tecniche immunochimiche quantitative per proteine
     2  104 to 1012 L/mol
     4  http://www.whfreeman.com/immunology/CH06/kuby06.htm
     6  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
     7  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.
     8  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 is compared with a standard of known properties. 1990, 62, 2202 IUPAC Compendium of Chemical Terminology 2nd Edition (1997)
     9  Rayleigh scattering (named after Lord Rayleigh) is the scattering of light 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 relation known as the Rayleigh law. Scattering from particles larger than about a tenth of the illuminating wavelength is handled by Mie theory. The intensity I of light scattered by a single small particle from a beam of light of wavelength ? and intensity I0 is given by:                                                        where R is 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.
     10  Optical System of a Nephelometer
     11  FilterTrak 660 Laser Nephelometer Optical Configuration
     12  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
     13  Clinical Chemistry and Laboratory Medicine Volume 39, Issue 11 (2001)                                                                    Søren Blirup-JensenProtein Standardization III: Method Optimization. Basic Principles for Quantitative Determination of Human 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 a suggestion 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 pre