Bouguer

INFRARED TECHNOLOGY AND RAMAN SPECTROSCOPY - INFRARED TECHNOLOGY] (Vol 14) Bouguer-Lambert-Beer Law... 

Transmission, Absorption, and Beer s Law. The majority of infrared spectrometry is stiU done by the classic method of transmission spectrometry the intensity of an infrared beam passing completely through a sample is measured. The standard description of how much radiation passes through the sample is that of Beet s law (or the Bouguer-Beer-Lambertlaw) ... 

Ultrasonic Spectroscopy. Information on size distribution maybe obtained from the attenuation of sound waves traveling through a particle dispersion. Two distinct approaches are being used to extract particle size data from the attenuation spectmm an empirical approach based on the Bouguer-Lambert-Beerlaw (63) and a more fundamental or first-principle approach (64—66). The first-principle approach implies that no caHbration is required, but certain physical constants of both phases, ie, speed of sound, density, thermal coefficient of expansion, heat capacity, thermal conductivity. 

Absorption spectroscopy records depletion by the sample of radiant energy from a continuous or frequency-tunable source, at resonance frequencies that are characteristic of various energy levels ia atoms or molecules. The basic law of absorption, credited to Bouguer-Lambert-Beer, states that ia terms of the iacident, Jq, and transmitted, light iatensities, the absorbance, M (or transmittance, T), is given by equation 1 ... 

M Bouguer, Essai d Optique sur la Gradation de la Lumiere. Paris, 1729 see also W Oswald Klassiker der Exakten Wissenschaften, No. 33, 58, 1891. M Bouguer, Traite d Optique sur la Gradation de la Lumiere, ouvrage posthume, Pub. de Lacaille, 1760... 

It is interesting to notice that these formulas are used to calculate the Bouguer correction. Now we will study the attraction field inside a layer when the coordinate of the observation point z satisfies the condition, (Fig.. Ah) z0. Then, the total field can be presented as a sum of two fields one of them is caused by masses with thickness equal h/2 — z,and the second one is due to masses in the rest of the layer, having the thickness z + A/2, (Fig. 1.14b). In accordance with Equation (1.146) these fields are... 

In the limiting case, when a strip becomes the plane of an infinite extension, we arrive at the well-known formula for the Bouguer correction. In fact, if q> = 7t/2 and q>2 — —w/2, we have... 

The Beer-Lambert law (also called the Beer-Lambert-Bouguer law or simply Beer s law) is the linear relationship between absorbance and concentration of an absorber of electromagnetic radiation. The general Beer-Lambert law is usually written as ... 

Beer s Law, 23 107. See also Beer-Lambert expression/law Lambert-Beer-Bouguer law quantitative analysis based on, 23 140-141... 

Bottom-up nanoscale fabrication, 24 61 Bottom-up technology, 17 45 Bouguer-Lambert-Beer law, 18 153 ... 

Lambda-cyhalothrin, in microcapsule formulations, 7 564t Lambda-derived cloning vectors, 12 504-506 Lambda sensor, 10 56 Lambent, commercial defoamer, 3 24 It Lambert-Beer-Bouguer law, 23 126. See also Beer s Law... 

Beer s law (Beer 1852), which, because it builds on earlier observations by Bouguer and Lambert, is also known as the Beer Lambert law. 

Beer-Lambert-Bouguer law See Bouguer-Lambert-Beer law. ba-3r lam-b3rt bti ger... 

Bouguer-Lambert-Beer law analy chem The intensity of a beam of monochromatic radiation in an absorbing medium decreases exponentially with penetration distance. Also known as Beer-Lambert-Bouguer law Lambert-Beer law. bCi ger lam bert ber, 16 ... 

The amount of light absorbed is a function of the so-called absorption coefficient (A ) and of the optical pathlength in the atomiser cell (ft) k depends on the frequency of the selected analytical line and on the concentration of the analyte absorbing atoms. The general absorbance law (Lambert Beer Bouguer law) relates transmittance (and so measured intensities I and If) to k and b through the following equation ... 

The main advantage of multivariate calibration based on CLS with respect to univariate calibration is that CLS does not require selective measurements. Selectivity is obtained mathematically by solving a system of equations, without the requirement for chemical or instrumental separations that are so often needed in univariate calibration. In addition, the model can use a large number of sensors to obtain a signal-averaging effect [4], which is beneficial for the precision of the predicted concentration, making it less susceptible to the noise in the data. Finally, for the case of spectroscopic data, the Lambert Bouguer Beer s law provides a sound foundation for the predictive model. 

The multivariate quantitative spectroscopic analysis of samples with complex matrices can be performed using inverse calibration methods, such as ILS, PCR and PLS. The term "inverse" means that the concentration of the analyte of interest is modelled as a function of the instrumental measurements, using an empirical relationship with no theoretical foundation (as the Lambert Bouguer-Beer s law was for the methods explained in the paragraphs above). Therefore, we can formulate our calibration like eqn (3.3) and, in contrast to the CLS model, it can be calculated without knowing the concentrations of all the constituents in the calibration set. The calibration step requires only the instrumental response and the reference value of the property of interest e.g. concentration) in the calibration samples. An important advantage of this approach is that unknown interferents may be present in the calibration samples. For this reason, inverse models are more suited than CLS for complex samples. 

Visual colorimetry, probably the oldest analytical method, was last used by the Greeks and Romans. This method found its scientific basis in 1729 when Pierre Bouguer theorised that if a given width of glass absorbs half of the light emitted by a source then double the width will reduce the fight by one quarter its initial value . 

A Historical Sketch, J. Chem. Ed 1961,38, 129. The equation that we call Beer s law embodies contributions by R Bouguer (1698-1758), J. H. Lambert (1728-1777), and A. Beer (1825-1863). Beer published his work in 1852, and similar conclusions were independently reached and published within a few months by F. Bernard. 

If appropriate corrections are made for scattering and related effects, tile ratio I/Io is given by the laws of Bouguer and Beer. Here, I0 is the intensity or radiant power of the light incident on the sample and / is tile intensity of the transmitted light. This ratio ///o = T is known as the transmittance. See also Spectrochemical Analysis (Visible). 

BOUGUER AND LAMBERT LAW. In homogeneous materials, such as glass or clear liquids, the fractional part of intensity or radiant energy absorbed is proportional to the thickness of the absorbing substance. 

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