Red 2G is a synthetic red azo dye. It is soluble in water and slightly soluble in

glycerol Glycerol (), also called glycerine in British English and glycerin in American English, is a simple triol compound. It is a colorless, odorless, viscous liquid that is sweet-tasting and non-toxic. The glycerol backbone is found in lipids known ...

. It usually comes as a disodium salt of 8-acetamido-1-hydroxy-2-phenylazonaphthalene-3,6 disulfonate.

Preparation

Red 2G is produced by

azo coupling In organic chemistry, an azo coupling is an organic reaction between a diazonium compound () and another aromatic compound that produces an azo compound (). In this electrophilic aromatic substitution reaction, the aryldiazonium cation is the ...

of Acetyl-H acid and diazonium derivative of

Aniline Aniline is an organic compound with the formula C6 H5 NH2. Consisting of a phenyl group attached to an amino group, aniline is the simplest aromatic amine. It is an industrially significant commodity chemical, as well as a versatile starti ...

under basic conditions: Synthese von Acid Red 1

Uses

Food dye

In the European Union, Red 2G was used as a

food dye Food coloring, or color additive, is any dye, pigment, or substance that imparts color when it is added to food or drink. They come in many forms consisting of liquids, powders, gels, and pastes. Food coloring is used in both commercial food ...

( E number E128). However, it was only permitted for use in breakfast sausages with a minimum cereal content of 6% and burger meat with a minimum vegetable and/or cereal content of 4%. Following safety concerns raised by EFSA in its opinion of 5 July 2007, the European Commission has prepared a draft Regulation to suspend use of E128 as a food colouring. This proposed course of action was unanimously approved by European Union Member States at a meeting of the Standing Committee of the Food Chain and Animal Health (Section Toxicological Safety of the Food Chain) on 20 July 2007. and Commission Regulation (EC) No 884/2007 on emergency measures suspending the use of E 128 Red 2G as food colour was published in the Official Journal of the European Union on 27 July 2007. Red 2G is also banned in Australia,

Canada Canada is a country in North America. Its ten provinces and three territories extend from the Atlantic Ocean to the Pacific Ocean and northward into the Arctic Ocean, covering over , making it the world's second-largest country by tot ...

, Japan,

Norway Norway, officially the Kingdom of Norway, is a Nordic country in Northern Europe, the mainland territory of which comprises the western and northernmost portion of the Scandinavian Peninsula. The remote Arctic island of Jan Mayen and the ...

, and

Malaysia Malaysia ( ; ) is a country in Southeast Asia. The federation, federal constitutional monarchy consists of States and federal territories of Malaysia, thirteen states and three federal territories, separated by the South China Sea into two r ...

. It was banned in

Israel Israel (; he, יִשְׂרָאֵל, ; ar, إِسْرَائِيل, ), officially the State of Israel ( he, מְדִינַת יִשְׂרָאֵל, label=none, translit=Medīnat Yīsrāʾēl; ), is a country in Western Asia. It is situated ...

in July 2007 . It is relatively insensitive to the

bleaching Bleach is the generic name for any chemical product that is used industrially or domestically to remove color (whitening) from a fabric or fiber or to clean or to remove stains in a process called bleaching. It often refers specifically, to ...

effect of sulfur dioxide (E220) and

sodium metabisulfite Sodium metabisulfite or sodium pyrosulfite (IUPAC spelling; Br. E. sodium metabisulphite or sodium pyrosulphite) is an inorganic compound of chemical formula Na2S2O5. The substance is sometimes referred to as disodium metabisulfite. It is used a ...

(E223). In the intestines, Red 2G can be converted to the toxic compound

aniline Aniline is an organic compound with the formula C6 H5 NH2. Consisting of a phenyl group attached to an amino group, aniline is the simplest aromatic amine. It is an industrially significant commodity chemical, as well as a versatile starti ...

, so there are concerns Red 2G may ultimately interfere with blood

haemoglobin Hemoglobin (haemoglobin BrE) (from the Greek word αἷμα, ''haîma'' 'blood' + Latin ''globus'' 'ball, sphere' + ''-in'') (), abbreviated Hb or Hgb, is the iron-containing oxygen-transport metalloprotein present in red blood cells (erythrocyte ...

, as well as cause cancer.

Inks

It is also used as a dye for coatings, inks, paper, crepe paper, and fine tissue.

Histology

Red 2G can be also used for staining in

histology Histology, also known as microscopic anatomy or microanatomy, is the branch of biology which studies the microscopic anatomy of biological tissues. Histology is the microscopic counterpart to gross anatomy, which looks at larger structures vi ...

, though rarely, e.g. as a component of Masson's trichrome.

Potential health risks

In July 2007, the EFSA established that E128 is potentially

carcinogen A carcinogen is any substance, radionuclide, or radiation that promotes carcinogenesis (the formation of cancer). This may be due to the ability to damage the genome or to the disruption of cellular metabolic processes. Several radioactive subs ...

ic because it forms

in the body when consumed. The pressure group, The Food Commission, said there had been concerns about Red 2G going back decades and it was suspected of being a

in the 1980s.{{cite news , first=Martin , last=Hickman , title= Additive used in sausages and burgers may cause cancer , date= 10 July 2007, url =https://www.independent.co.uk/living/food_and_drink/news/article2750462.ece , archive-url =https://web.archive.org/web/20070712193359/http://www.independent.co.uk/living/food_and_drink/news/article2750462.ece , url-status =dead , archive-date =July 12, 2007 , work =The Independent , access-date = 2007-07-10 , location=London

References

Azo dyes Food colorings Staining dyes Organic sodium salts Acetamides 1-Naphthols Naphthalenesulfonates