Monoethanolamine Raw Material Testing Procedure

Monoethanolamine (MEA) is a colorless liquid used as a cleaning agent and chemical intermediate in various industries. Monoethanolamine Raw Material Testing Procedure its purity and quality, the following analytical methods can be used:

pH measurement: Monoethanolamine has a basic pH due to its amine functional group. The pH of a sample can be measured using a pH meter or indicator paper.
Titration: This method involves slowly adding a standard acid solution to a sample of MEA until the solution reaches its equivalence point, indicated by a change in pH or color. The volume of acid required to reach the equivalence point can be used to determine the concentration of MEA in the sample.
Gas chromatography (GC): This method separates and quantifies the components of a sample using a gas chromatography column. The sample is vaporized and injected into the column, and the MEA is separated based on its properties and then quantified.
Infrared spectroscopy (IR): This method involves measuring the absorption of infrared light by a sample. The resulting spectrum can be used to identify and confirm the presence of specific chemical functional groups in the sample, such as the amine group in MEA.


To ensure the quality of incoming raw material of Monoethanolamine


It is applicable for the analysis of Monoethanolamine in the quality control department.


  • Quality Control Manager
  • Assist. Q.C. Manager
  • Q.C Analyst


  1. SAP: Standard Analytical Procedure
  2. QC: Quality control


Monoethanolamine Raw Material Testing Procedure


  • Gas Chromatography System with Accessories
  • Analytical Balance
  • Calibrated Glass Ware
  • Hot Plate
  • Oven
  • Ice Bath
  • Water Bath
  • Refractometer
  • Melting Point Apparatus
  • Reflux Condenser
  • Litmus Paper


  1. Distilled Water
  2. Ethanol 90%, 96%
  3. Ether
  4. Dichloromethane
  5. 3-Aminopropan-1-ol
  6. Ethanolamine
  7. Diethanolamine
  8. Triethanolamine
  9. Trifluoroacetic Anhydride
  10.  Picric Acid
  11. 1M Hydrochloric Acid
  12. 1M Sodium Hydroxide
  13. Methyl Red Solution

Physical Analysis

This analysis is done by Analyst with the help of Laboratory Assistant.

Test of Physical Form:

Check the sample and confirm its physical form; it should be clear liquid.

Test of Colour:

Confirm the colour of the material with naked eye; it should be colourless or pale yellow.

Test of Solubility:

Water: Miscible
Ethanol (96%): Miscible
Ether: Slightly soluble

Test of Refractive Index:

Cool the liquid and distilled water upto 20 ± 0.5ºC in ice bath and note the refractive index comparing with water using refractometer.
It should be 1.453 – 1.459.

Test of Weight / ml:

Determine the weight of the substance per ml; it should be 1.014 – 1.023g.

Record the result of Physical Analysis on Raw Material Analysis Log Book.

Limit Test:

Related Substances:

Examine by Gas Chromatography.

Solution A:

Prepare a 0.1% w/v solution of 3-aminopropan-1-ol (internal standard) in dichloromethane.

Solution (1):

Prepare a solution containing 0.05% w/v of ethanolamine and 0.1% w/v each of diethanolamine and triethanolamine in solution A. To 0.5 ml of this solution add 0.5 ml of trifluoroacetic anhydride, mix and allow to stand for 10 minutes.

Solution (2):

Prepare a 10% w/v solution of the sample in solution A. To 0.5 ml of this solution add 0.5 ml of trifluoroacetic anhydride, mix and allow to stand for 10 minutes.

Chromatographic System:

Column: 25m x 0.22mm fused silica capillary column, bonded with a 0.25 µm layer of dimethylpolysiloxane
Carrier gas: Helium
Flow rate: 1 ml / min
Split ratio: 40 : 1


Injection Port: 240°C
Detector: 250°C
Column: 80°C for 2 minutes, then increase to 200°C and maintain this temperature for 10 minutes


In the chromatogram obtained with solution (1) the peaks eluting after the solvent peak in order of emergence are due to (a) ethanolamine, (b) 3-aminopropan-1-ol, (c) diethanolamine and (d) triethanolamine. In the chromatogram obtained with solution (2) calculate the content of diethanolamine and triethanolamine by reference to the corresponding peaks in the chromatogram obtained with solution (1). Calculate the content of any other impurity by reference to the peak due to ethanolamine in the chromatogram obtained with solution (1).


  • The contents of diethanolamine and triethanolamine is not more than 1.0% w/w of each.
  • The content of any other impurity is not more than 0.5% w/w.
  • The sum of the contents of all the impurities is not more than 2.0% w/w.

Record the result of Limit Tests on Raw Material Analysis Log Book.

Chemical Analysis:

Identification Test of Mono ethanolamine:

  • To 0.1 ml of the sample add 0.3 g of picric acid and 1 ml of water and evaporate to dryness on a water bath. The melting point of the residue, after recrystallization from ethanol (96%) and drying at 105°C, is about 160°C.
  • When freshly distilled the second half of the distillate freezes at about 10°C.
  • Prepare a litmus solution by boiling 25 g of coarsely powdered litmus with 100 ml of ethanol (90%) under a reflux condenser for 1 hour, discard the clear liquid and repeat this operation using two 75 ml quantities of ethanol (90%). Digest the extracted litmus with 250 ml of water and filter.
    It is alkaline to litmus solution.

Contents of Monoethanolamine:

Dissolve 2.5 g of the sample in 50 ml of 1M hydrochloric acid VS and titrate the excess of acid with 1M sodium hydroxide VS using methyl red solution as indicator. Carry out blank titration.


  • Volume of 1M Sodium Hydroxide used for sample = A ml
  • Volume of 1M Sodium Hydroxide used for blank = B ml
  • Difference = A – B = C ml
  • Note the readings.


Calculate the contents of Monoethanolamine as follows:

Factor: Each ml of 1M hydrochloric acid VS is equivalent to 61.08 mg of monoethanolamine.

C x Factor
———– x 100 = S

Limit: The contents of monoethanolamine should be 98.0 – 100.5%.

Quality Record(s)/Form(s):

The following Quality Records shall be generated and managed in accordance with the Procedure for Control of Company Quality Records.


It’s important to follow all relevant safety guidelines and regulations when handling and testing MEA, and to ensure that the analytical methods used are validated and appropriate for the specific product and application. Additionally, it’s recommended to use properly calibrated and maintained equipment, and to follow good laboratory practices (GLP) to ensure the accuracy and reliability of the test results.

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