Wavelength Photometry
Wavelength Photometry - Related Videos
02:32
The de Broglie Wavelength
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2020
In the macroscopic world, objects that are large enough to be seen by the naked eye follow the rules of classical physics. A billiard ball moving on a table will behave like a particle; it will continue traveling in a straight line unless it collides with another ball, or it is acted on by some other force, such as friction. The ball has a well-defined position and velocity or well-defined momentum, p = mv, which is defined by mass m and velocity v at any given moment. This is the typical...
07:49
Simultaneous Photothrombosis and Fiber Photometry to Induce and Monitor Ischemic Stroke in Behaving Mice
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2025
Using an all-optical approach, ischemic stroke is induced while simultaneously recording neuronal Ca2+ activity using a fluorescent biosensor in the emerging stroke core of an awake, behaving mouse.
05:16
Mass Photometry to Study Antigen-Antibody Interactions on a Single-Molecule Level
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2025
In this video, we demonstrate the use of mass photometry to study antigen-antibody interactions in a flow chamber. The focused light scatters differently based on the mass of the molecules. A detector collects the scattered light and generates the interference pattern as spots of varied intensities, which correlate with the molecular masses.
01:02
Flame Photometry: Overview
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2024
Flame photometry, also known as flame emission spectrometry, is a technique used for the qualitative and quantitative analysis of elements present in a sample using a flame as the source of excitation energy. The concept of flame photometry was realized in the early 1860s by Kirchhoff and Bunsen, who discovered that specific elements emit characteristic radiation when excited in flames. The first instrument developed for this purpose was used to measure sodium (Na) in plant ash using a Bunsen...
01:16
Flame Photometry: Lab
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2024
In a flame photometer, when a solution like potassium chloride is aspirated into the flame, the solvent evaporates, leaving behind dehydrated salt. This salt dissociates into free gaseous atoms in their ground state. Some of these atoms absorb energy from the flame, leading to their excitation. The excited atoms return to the ground state, emitting photons at characteristic wavelengths. Because only electronic transitions are involved, the resulting emission lines are very narrow. The intensity...
FAQs
Selecting a wavelength targets the part of the optical signal that carries information about the sample. Depending on the biological material and measurement mode, the sample may absorb, transmit, or emit light at that wavelength. The detector converts the resulting intensity into data that can be interpreted to characterize the sample or follow a biological change.
Beer–Lambert analysis is useful because it connects measured absorbance with analyte concentration, but only under appropriate conditions. The selected wavelength, sample response, and measurement conditions therefore affect how confidently absorbance can be converted into a concentration estimate. In biological experiments, this relationship supports quantitative comparisons when those conditions are maintained across samples.
Both components isolate the wavelength reaching the detector, but they provide alternative approaches to wavelength selection. A filter selects a specified portion of the light, whereas a monochromator isolates a wavelength within the instrument. This distinction matters when choosing a photometer or spectrophotometer for measurements that require controlled optical selection.
A basic workflow begins by choosing the wavelength relevant to the biological measurement, placing the sample in a photometer or spectrophotometer, isolating that wavelength with a filter or monochromator, and recording detector intensity. The signal can then be expressed as absorbance or interpreted as transmitted or emitted light, depending on the measurement and the experimental goal.
Wavelength photometry can support analysis of nucleic acids, proteins, pigments, and enzyme reactions. These applications use optical measurements to quantify biomolecules or assess changes in reaction-related signals. The resulting data help characterize a biological sample, compare measurements, and monitor how a system changes during an experiment.
Fluorescence measurements add a signal pathway for studying labeled molecules and cellular processes. The experiment can follow light emitted by a fluorescent sample and examine changes in that signal. This makes the approach useful when the research question concerns molecular labels or dynamic events within biological systems.