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27 kwi 2024 · Fluorimetry Principle. Fluorimetry is based on the principle of emission of light by a substance after the absorption of light of a specific wavelength. With the absorption of light, the fluorophores in the samples get excited moving to a state of higher energy.
16 gru 2022 · Principle of Colorimeter. When an incident light beam with intensity I 0 passes through a solution, a part of the incident light is reflected (I r) and absorbed (I a) while the remaining incident light is transmitted (I t). i.e., I o = I r + I a + I t.
10 cze 2021 · In many metabolic tests, end products are produced that change the pH of the medium. To measure this pH change, pH indicators (chemicals that change color depending on pH) are included in the medium. Some common pH indicators are phenol red, bromocresol purple, and bromothymol blue.
1 mar 2001 · A Jablonski diagram is used to represent the energy levels of a molecule. These energy levels include the ground electronic state (S 0), which typifies a molecule “at rest” and also higher energy electronic states (e.g., S 1, S 2), reached upon the absorption of light. Each electronic state of a molecule also contains numerous vibrational ...
10 wrz 2021 · Spectrophotometers are instruments designed to detect the amount of light energy that is absorbed or transmitted by molecules dissolved in a solution. Since molecules have wavelengths unique to their structure, different chemicals and their concentrations can be identified based on their absorbance or transmittance.
Photochemistry is the underlying mechanism for all of photobiology. When a molecule absorbs a photon of light, its electronic structure changes, and it reacts differently with other molecules. The energy that is absorbed from light can result in photochemical changes in the absorbing molecule, or in an adjacent molecule (e.g., photosensitization).
10 cze 2021 · A simple test to determine if bacteria produce catalase is to add hydrogen peroxide to bacteria on an agar slant or to bacteria spread on a slide (image 1). If catalase is present, the hydrogen peroxide will be broken down into water and oxygen gas, resulting in the production of bubbles (+ test).
