Phenol Red Marker
Phenol Red Marker - Related Videos
01:46
Quantification of Tear Volume in an Autoimmune Dry Eye Rat Model using the Phenol Red Thread
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2025
This video demonstrates the phenol red thread test to determine tear volume in an autoimmune dry eye rat model. The pH-sensitive acidic phenol red thread changes color when it comes in contact with the alkaline tears. The shorter length of color change in the phenol red thread corresponds to reduced tear volume.
08:16
Phenol Red Thread-based Sampling Procedure for Untargeted Tear Fluid Lipidomics in Biomarker Discovery
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2025
This protocol describes a unique clinical protocol for collecting human tear fluid samples using phenol red threads and liquid chromatography-tandem mass spectrometry (LC-MS/MS)-based workflow to discover the tear lipidomic profile. The simple methyl tert-butyl ether (MTBE)/methanol biphasic separation method enables rapid tear lipid extraction with high recovery for tear biomarker discovery.
01:17
Oxidation of Phenols to Quinones
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2025
In the presence of oxidizing agents, phenols are oxidized to quinones. Quinones can be easily reduced back to phenols using mild reducing agents. The electron-donating hydroxyl group enhances the reactivity of the aromatic ring, enabling oxidation of the ring even in the absence of an α hydrogen. o-hydroxy phenols are oxidized to o-quinones and p-hydroxy phenols to p-quinones. Such redox reactions involve the transfer of two electrons and two protons. The reversible redox property is crucial in...
02:23
Structure and Nomenclature of Alcohols and Phenols
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2023
Overview Alcohols are one of the most important functional groups in organic chemistry. The name of alcohol comes from the hydrocarbon from which it is derived. Alcohols are organic molecules containing the functional hydroxyl or –OH group directly bonded to carbon. Phenols have an OH group directly attached to a benzene ring. While alcohols are colorless, phenol is a white crystalline compound with a characteristic "hospital smell" odor. As with other organic compounds, alcohols and phenols...
02:32
Physical Properties of Alcohols and Phenols
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2023
Alcohols are organic compounds in which a hydroxy group is attached to a saturated carbon. Phenols are a class of alcohols containing a hydroxy group attached to an aromatic ring. The physical properties of the alcohols and phenols are influenced by hydrogen bonding due to the oxygen–hydrogen dipole in the hydroxy functional group and dispersion forces between alkyl or aryl regions of alcohol and phenol molecules. Alcohols possess a higher boiling point than aliphatic hydrocarbons of similar...
FAQs
The indicator’s color response comes from a reversible change in its molecular structure as hydrogen-ion concentration changes. Because that structural shift tracks acidity or alkalinity, the visible color does not represent a permanent reaction in the sample. Instead, it provides a direct visual signal that the chemical environment has moved within the indicator’s transition range.
In cell-culture media, a shift from red toward yellow commonly signals increasing acidity, whereas movement toward pink or purple indicates more alkaline conditions. These colors should be read as directional evidence of pH change rather than as a standalone explanation for its cause. The observation tells users that the medium’s chemical environment has changed.
Because its color change is reversible, the marker can signal that the medium has shifted rather than simply recording a completed, irreversible event. This supports ongoing observation of biological samples, allowing researchers to notice changing culture conditions while avoiding immediate disturbance. The feature is especially useful when monitoring experiments over time.
The transition range determines which hydrogen-ion concentrations produce visibly different forms of the indicator. Consequently, a color change becomes informative when the sample’s acidity or alkalinity moves through that range. In biological monitoring, this helps users connect a visible shift with a change in the medium’s chemical environment, without treating every color difference as a separate process.
During routine culture checks, observers can inspect the medium and record whether its color remains red or shifts toward yellow, pink, or purple. The direction of change provides a quick indication that acidity or alkalinity has moved. Because the sample need not be immediately disturbed, the marker supports convenient tracking of culture conditions during an experiment.
A shift can serve as an early sign that deserves investigation rather than a diagnosis by itself. In cell-culture media, increasing acidity may be associated with metabolic activity, while unexpected changes can point to contamination or handling problems. The marker therefore helps researchers decide when culture conditions warrant closer attention and additional evaluation.