Sudan IV
Encyclopedia
Sudan IV is a lysochrome
(fat-soluble dye) diazo dye used for the staining
of lipids, triglycerides and lipoproteins on frozen paraffin
sections. It has the appearance of reddish brown crystals with melting point 199 °C and maximum absorption at 520(357) nm.
Sudan IV is one of the dyes used for Sudan stain
ing. Similar dyes include Oil Red O
, Sudan III
, and Sudan Black B
. Staining is an important biochemical technique, offering the ability to visually qualify the presence of the fatty compound of interest without isolating it. For staining purposes Sudan IV can be made up in propylene glycol
http://www.ihcworld.com/_protocols/special_stains/oil_red_o.htm. Alternatively, authors have reported using the dye saturated in isopropyl alcohol
, 95% ethanol
, or 0.05% by weight in acetone:ethanol:water (50:35:15). The idea is to use a moderately apolar solvent to solubilize the dye allowing it to partition into the highly apolar fat without the solvent solubilizing the fat to be stained.
Sudan I
, Sudan III
, and Sudan IV have been classified as category 3 carcinogen
s by the International Agency for Research on Cancer
.
In its purified form it is called Biebrich scarlet R, which should not be confused with the water-soluble Biebrich scarlet
.
In industry, it is used to color nonpolar substances like oil
s, fat
s, wax
es, grease
s, various hydrocarbon
products, and acrylic
emulsion
s. Sudan IV is also used in United Kingdom
as a fuel dye to dye lower-taxed heating oil
; because of that it is also known as Oil Tax Red. As a food dye, Sudan IV is considered an illegal dye, mainly because of its harmful effect over a long period of time, as it is a carcinogen
. It was ruled unsafe in the 1995 food safety regulations report.
Lysochrome
A lysochrome is a soluble dye used for biochemical staining of triglycerides, fatty acids, and lipoproteins. Lysochromes such as Sudan IV bind to the lipid in a substrate and show up as colored regions. The dye does not stick to any other substrates, so a quantification or qualification of lipid...
(fat-soluble dye) diazo dye used for the staining
Staining (biology)
Staining is an auxiliary technique used in microscopy to enhance contrast in the microscopic image. Stains and dyes are frequently used in biology and medicine to highlight structures in biological tissues for viewing, often with the aid of different microscopes...
of lipids, triglycerides and lipoproteins on frozen paraffin
Paraffin
In chemistry, paraffin is a term that can be used synonymously with "alkane", indicating hydrocarbons with the general formula CnH2n+2. Paraffin wax refers to a mixture of alkanes that falls within the 20 ≤ n ≤ 40 range; they are found in the solid state at room temperature and begin to enter the...
sections. It has the appearance of reddish brown crystals with melting point 199 °C and maximum absorption at 520(357) nm.
Sudan IV is one of the dyes used for Sudan stain
Sudan stain
Sudan staining is the use of Sudan dyes to stain sudanophilic substances, usually lipids. Sudan lysochromes are used....
ing. Similar dyes include Oil Red O
Oil Red O
Oil Red O is a lysochrome diazo dye used for staining of neutral triglycerides and lipids on frozen sections and some lipoproteins on paraffin sections...
, Sudan III
Sudan III
Sudan III is a lysochrome diazo dye used for staining of triglycerides in frozen sections, and some protein bound lipids and lipoproteins on paraffin sections. It has the appearance of reddish brown crystals and a maximum absorption at 507 nm.Sudan III is a dye used for Sudan staining...
, and Sudan Black B
Sudan Black B
Sudan Black B is a lysochrome diazo dye used for staining of neutral triglycerides and lipids on frozen sections and some lipoproteins on paraffin sections. It has the appearance of a dark brown to black powder with maximum absorption at 596-605 nm and melting point 120-124 °C...
. Staining is an important biochemical technique, offering the ability to visually qualify the presence of the fatty compound of interest without isolating it. For staining purposes Sudan IV can be made up in propylene glycol
Propylene glycol
Propylene glycol, also called 1,2-propanediol or propane-1,2-diol, is an organic compound with formula C3H8O2 or HO-CH2-CHOH-CH3...
http://www.ihcworld.com/_protocols/special_stains/oil_red_o.htm. Alternatively, authors have reported using the dye saturated in isopropyl alcohol
Isopropyl alcohol
Isopropyl alcohol is a common name for a chemical compound with the molecular formula C3H8O. It is a colorless, flammable chemical compound with a strong odor...
, 95% ethanol
Ethanol
Ethanol, also called ethyl alcohol, pure alcohol, grain alcohol, or drinking alcohol, is a volatile, flammable, colorless liquid. It is a psychoactive drug and one of the oldest recreational drugs. Best known as the type of alcohol found in alcoholic beverages, it is also used in thermometers, as a...
, or 0.05% by weight in acetone:ethanol:water (50:35:15). The idea is to use a moderately apolar solvent to solubilize the dye allowing it to partition into the highly apolar fat without the solvent solubilizing the fat to be stained.
Sudan I
Sudan I
Sudan I , is a lysochrome, a diazo-conjugate dye with the chemical formula of 1-phenylazo-2-naphthol. Sudan I is a powdered substance with an orange-red appearance. The additive is mainly used to colour waxes, oils, petrol, solvents and polishes...
, Sudan III
Sudan III
Sudan III is a lysochrome diazo dye used for staining of triglycerides in frozen sections, and some protein bound lipids and lipoproteins on paraffin sections. It has the appearance of reddish brown crystals and a maximum absorption at 507 nm.Sudan III is a dye used for Sudan staining...
, and Sudan IV have been classified as category 3 carcinogen
Carcinogen
A carcinogen is any substance, radionuclide, or radiation that is an agent directly involved in causing cancer. This may be due to the ability to damage the genome or to the disruption of cellular metabolic processes...
s by the International Agency for Research on Cancer
International Agency for Research on Cancer
The International Agency for Research on Cancer is an intergovernmental agency forming part of the World Health Organisation of the United Nations....
.
In its purified form it is called Biebrich scarlet R, which should not be confused with the water-soluble Biebrich scarlet
Biebrich scarlet
Biebrich scarlet is a molecule used in Lillie's trichrome....
.
In industry, it is used to color nonpolar substances like oil
Oil
An oil is any substance that is liquid at ambient temperatures and does not mix with water but may mix with other oils and organic solvents. This general definition includes vegetable oils, volatile essential oils, petrochemical oils, and synthetic oils....
s, fat
Fat
Fats consist of a wide group of compounds that are generally soluble in organic solvents and generally insoluble in water. Chemically, fats are triglycerides, triesters of glycerol and any of several fatty acids. Fats may be either solid or liquid at room temperature, depending on their structure...
s, wax
Wax
thumb|right|[[Cetyl palmitate]], a typical wax ester.Wax refers to a class of chemical compounds that are plastic near ambient temperatures. Characteristically, they melt above 45 °C to give a low viscosity liquid. Waxes are insoluble in water but soluble in organic, nonpolar solvents...
es, grease
Grease (lubricant)
The term grease is used to describe semisolid lubricants. Although the word grease is also used to describe rendered fat of animals, in the context of lubrication, grease typically applies to a material consisting of a soap emulsified with mineral or vegetable oil...
s, various hydrocarbon
Hydrocarbon
In organic chemistry, a hydrocarbon is an organic compound consisting entirely of hydrogen and carbon. Hydrocarbons from which one hydrogen atom has been removed are functional groups, called hydrocarbyls....
products, and acrylic
Acryl group
In organic chemistry, the acryloyl group is the functional group with structure H2C=CH–C–; it is the acyl group derived from acrylic acid. The preferred IUPAC name for the group is prop-2-enoyl, and it is also known as acrylyl or simply acryl...
emulsion
Emulsion
An emulsion is a mixture of two or more liquids that are normally immiscible . Emulsions are part of a more general class of two-phase systems of matter called colloids. Although the terms colloid and emulsion are sometimes used interchangeably, emulsion is used when both the dispersed and the...
s. Sudan IV is also used in United Kingdom
United Kingdom
The United Kingdom of Great Britain and Northern IrelandIn the United Kingdom and Dependencies, other languages have been officially recognised as legitimate autochthonous languages under the European Charter for Regional or Minority Languages...
as a fuel dye to dye lower-taxed heating oil
Heating oil
Heating oil, or oil heat, is a low viscosity, flammable liquid petroleum product used as a fuel for furnaces or boilers in buildings. Home heating oil is often abbreviated as HHO...
; because of that it is also known as Oil Tax Red. As a food dye, Sudan IV is considered an illegal dye, mainly because of its harmful effect over a long period of time, as it is a carcinogen
Carcinogen
A carcinogen is any substance, radionuclide, or radiation that is an agent directly involved in causing cancer. This may be due to the ability to damage the genome or to the disruption of cellular metabolic processes...
. It was ruled unsafe in the 1995 food safety regulations report.
External links
- Stains File entry