Table of Contents

• Introduction
• Safety Precautions
• Material and Equipment Requirements
• Sample Preparation
• Common Laboratory Tests with Ethanol
• 4.1. Specific Gravity Test
• 4.2. Flash Point Test
• 4.3. Water Content Test
• 4.4. Acidity Test
• 4.5. GC-MS Analysis
• Data Analysis and Interpretation
• Clean-Up and Waste Disposal
• References

Introduction

Ethanol (C2H5OH), also known as ethyl alcohol, is a versatile solvent that’s frequently used in laboratories for various experimental procedures. This booklet is designed to guide users through laboratory testing and analysis using high-purity ethanol (99.9%).

Safety Precactions

Ethanol is highly flammable and can cause skin and eye irritation. Here are some safety measures to follow while handling ethanol:

Always use ethanol in a well-ventilated area.
Wear suitable protective clothing, including gloves and safety goggles.
Avoid open flames and high temperatures as ethanol is highly flammable.
Use spill-containment equipment to prevent environmental contamination.

Material and Equipment Requirements

• 99.9% purity Ethanol
• Pipettes and Bulbs
• Beakers
• Graduated Cylinder
• Electronic Balance
• Hydrometer
• Flash Point Tester
• Karl Fischer Titrator
• pH Meter
• Gas Chromatography-Mass Spectrometry (GC-MS) Equipment

Sample Preparation

Before conducting any tests, it’s essential to prepare your ethanol sample properly. Make sure all tools and surfaces are clean and free from contamination. Follow precise measurement protocols to ensure your sample is representative of the ethanol you are testing.

Common Laboratory Tests with Ethanol

Specific Gravity Test

The specific gravity of ethanol changes with temperature and alcohol concentration. Using a hydrometer and temperature correction tables, you can measure the specific gravity of your sample.

Flash Point Test

The flash point is the lowest temperature at which ethanol can vaporize to form an ignitable mixture in air. Using a flash point tester, you can determine the flash point of your ethanol sample.

Water Content Test

Karl Fischer titration is commonly used to determine the water content in ethanol. The reaction involves the oxidation of sulfur dioxide by iodine in the presence of water, resulting in the formation of sulfuric acid.

Acidity Test

The acidity of ethanol can be measured using a pH meter. Be sure to calibrate your pH meter before testing to ensure accurate results.

GC-MS Analysis

Gas chromatography-mass spectrometry (GC-MS) is a method that combines the features of gas-chromatography and mass spectrometry to identify different substances within a test sample. GC-MS can be used to analyze the purity of the ethanol and identify any trace impurities.

Data Analysis and Interpretation

After conducting the tests, it’s essential to analyze and interpret the data correctly:

Compare the specific gravity, flash point, and acidity to standard values for ethanol.
A lower than expected flash point might indicate the presence of more volatile impurities.
A higher water content can decrease the ethanol concentration.
In GC-MS analysis, compare the obtained spectra with reference spectra to identify any impurities.

Clean-Up and Waste Disposal

After completing the tests, clean all equipment thoroughly and follow your institution’s guidelines for waste disposal. Ethanol waste should be collected in a suitable container for hazardous waste and not poured down the drain.

References

Material Safety Data Sheet (MSDS) for Ethanol
ASTM Standards for Ethanol Testing
“Laboratory Safety: Principles and Practices”, 2nd Edition, by Diane Fleming and Janine H. Trevor