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In physics, spectrophotometry is the quantitative study of electromagnetic spectra. It is more specific than the general term electromagnetic spectroscopy in that spectrophotometry deals with visible light, near-ultraviolet, and near-infrared. Also, the term does not cover time-resolved spectroscopic techniques. Spectrophotometry involves the use of a spectrophotometer. A spectrophotometer is a photometer (a device for measuring light intensity) that can measure intensity as a function of the color, or more specifically, the wavelength of light. There are many kinds of spectrophotometers. Among the most important distinctions used to classify them are the wavelengths they work with, the measurement techniques they use, how they acquire a spectrum, and the sources of intensity variation they are designed to measure. Other important features of spectrophotometers include the spectral bandwidth and linear range. Perhaps the most common application of spectrophotometers is the measurement of light absorption, but they can be designed to measure diffuse or specular reflectance. Strictly, even the emission half of a luminescence instrument is a kind of spectrophotometer. The use of spectrophotometers is not limited to studies in physics. They are also commonly used in other scientific fields such as chemistry, biochemistry, and molecular Biology.
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What is the advantage of a spectrophotometer?
A spectrophotometer allows for quantitative analysis of a sample's concentration or purity by measuring its absorbance or transmission of light at different wavelengths. It is highly sensitive and precise, providing accurate measurements in a wide range of applications such as chemistry, biology, and environmental science. Its versatility and ability to quickly analyze multiple samples make it a valuable tool in research and quality control.
Does spectrophotometer and spectroflorimeter are same?
They both measure fluorescence, but a spectrofluorometer usually has adjustable excitation and emission wavelengths via a monochromator; whereas a fluorometer usually measures fixed wavelengths either by filters, monochromators or fixed diodes. Spectrofluorometers are more flexible but fluorometers are much more sensitive, usually 100-1000x more sensitive.
What is the principle of colorimeter?
Beer and Lambert's law states that 'when a ray of monochromatic light passes through a solution in a transparent vessel, intensity of transmitted light depends on concentration of absorbing solution and path length of absorbing medium.'A=ebcWhere A is absorbance (no units, since A = log10P0 / P )e is the molar absorbtivity with units of L mol-1 cm-1b is the path length of the sample - that is, the path length of the cuvette in which the sample is contained. We will express this measurement in centimetres.c is the concentration of the compound in solution, expressed in mol L-1when path length is kept constant ansorbance is proportional to concentration of substance. Path length for a colorimeter is constant.Different substances absorb light of different frequencies maximally. Light of appropriate frequency is passed through solution using different filters in colorimeter and % transmission is measured. e.g. proteins absorb light of 650nm.Error is eliminated by calliberatin blank(solution without test substance) as 100% transmission ie zero absorbance, and black stop as 0% transmission. Thus we get absorbance of only required substance.% transmission is converted to absorbance using following expressionA = 2 - log10 %T
