Sodium hydroxide often handled as an aqueous solution used for the manufacture of sodium salts and detergents, It is used as industrial cleaning and sanitation agent used in removing chromatographic contaminants

1. Applications of Sodium
Hydroxide (Caustic Soda)
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2. Introduction
 Sodium hydroxide is the principal strong base used in the
chemical industry. In bulk it is most often handled as an
aqueous solution, since solutions are cheaper and easier to
handle. Sodium hydroxide is also used for the manufacture of
sodium salts and detergents, for pH regulation, and for
organic synthesis.
 Sodium hydroxide is employed to digest tissues, such as in a
process that was used with farm animals at one time. This
process involved placing a carcass into a sealed chamber, then
adding a mixture of sodium hydroxide and water. This
eventually turns the body into a liquid with coffee-like
appearance and the only solid that remains are bone hulls,
which could be crushed between one's fingertips.

3. Sodium Hydroxide as Cleaning Agent
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Sodium hydroxide is widely accepted for cleaning, sanitizing, and storing chromatography
media and systems. The advantages of sodium hydroxide as a cleaning and sanitation agent are
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Efficacy
Low cost
Ease of detection
Removal
Disposal
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Sodium hydroxide has been shown to be effective in removing proteins and nucleic acids. It is
also effective for inactivating
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Viruses
Bacteria
Yeasts
Fungi
Endotoxins
It is common practice in industrial manufacturing to save time by adding a salt, such as sodium
chloride, to the sodium hydroxide solution to combine cleaning with sanitization.

4. Sodium Hydroxide used in Pharmaceuticals
 During restrictive inspections, producers of
biopharmaceuticals and biological products usually give
attention to cleaning and cleaning validation of
chromatography resins and multiuse purification
systems. Chromatographic resins must either be
disposed of or sufficiently cleaned to ensure
reproducibility in subsequent cycles.
 Over the years, varied cleaning agents have been
proposed. Once evaluating a new cleaning agent for a
resin, make sure it is compatible with system
components as well. Destruction of O-rings and other
column components by a cleaning agent is a risk to a
process.

5. Sodium hydroxide cleaning resins
 For resins, the foremost cleaning agent is sodium hydroxide. Some
reports indicate that heated sodium hydroxide is an excellent
cleaning agent. Even without the heating, high concentrations of
sodium hydroxide require facility and equipment evaluation and use
of safety equipment to protect workers.
 Sodium hydroxide is frequently used as an industrial cleaning agent
where it is often called "caustic". It is added to water, heated, and
then used to clean process equipment, storage tanks, etc. It can
dissolve grease, oils, fats and protein based deposits. It is also used
for cleaning waste discharge pipes under sinks and drains in
domestic properties.
 As a cleaning agent, sodium hydroxide saponifies fats and dissolves
proteins. In general, it can solubilize precipitated proteins. Its
hydrolyzing power is enhanced by the presence of chlorine.

6. Sodium Hydroxide in Chromatography Columns
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Chromatography columns can become contaminated by a variety of protein and nonprotein
species during a purification process. Consequences of chromatography column contamination
include
Increase in backpressure
Loss of signal resolution
Altered product yield
Medium discoloration
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Common chromatographic contaminants include
Residual proteins
Proteins
Nucleic acids
Lipids
Viruses
Bacteria
Yeast
Fungi
Prions
Endotoxins
Metal ions
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7. Sodium hydroxide for proteins removal
 Sodium hydroxide has been used extensively to get rid of
proteins from ion exchange, hydrophobic interaction, and gel
filtration media. The ability of sodium hydroxide to remove
proteins from chromatography media depends on the
following factors
 Nature of the media
 Nature of sample
 Sample contaminants
 These factors may interfere with the cleaning efficiency of
sodium hydroxide. A higher concentration of sodium
hydroxide may be required if lipids are bound to a protein.

8. Sodium hydroxide for nucleic acids
removal
 Nucleic acids can bind tenaciously to anion exchangers of chromatography
equipment. 1 M sodium hydroxide and 3 M sodium chloride, with a total contact
time of one hour, effectively removes radiolabelled calf thymus DNA from a weak
anion exchanger.
 Since it is a bacteriostat it is recommended for the removal of bacteria from
chromatography equipment sodium hydroxide should be added along with ethanol.
Sodium hydroxide may not completely eliminate bacterial spores alone in further
good manufacturing process required to complete the process.
 Endotoxins are effectively removed by using sodium hydroxide sanitizing agent.
 When sodium hydroxide used for sanitization of chromatography media, the ability
to withstand stringent sanitizing conditions depends on the following factors
 Functional groups
 Attachment chemistries
 Stability of base matrices to alkaline conditions

9. References
 Reference
 [1] © From GE Healthcare Bio-Sciences AB,
https://www.gelifesciences.com/gehcls_images/GE
LS/Related%20Content/Files/1338541738309/litdo
c18112457_20131118232545.pdf

10. Other applications
 Food uses of sodium hydroxide include washing or
chemical peeling of fruits and vegetables, chocolate
and cocoa processing, caramel coloring production,
poultry scalding, soft drink processing, and
thickening ice cream.
 Olives are often soaked in sodium hydroxide to
soften them, while pretzels and German lye rolls are
glazed with a sodium hydroxide solution before
baking to make them crisp.
 Sodium hydroxide has been used to straighten hair