How to handle Gas Chromatographic Gases Safely?

Gas chromatography analysis requires high purity compressed gases. The three Gas Chromatographic gases commonly used are:

Inert Carrier Gas – Helium or Nitrogen

Fuel Gas – Hydrogen (FID operation)

Combustion Support Gas – Air (FID operation)

Colour Coding of Gases

Color Coding of Gas Cylinders

The Gas Chromatographic gases are supplied in compressed gas cylinders which are colour coded and require careful handling to prevent accidents. Air and inert gases do not pose major hazards, except accidents that could result from careless handling.

Hydrogen

In addition to its use as a combustion gas hydrogen is an ideal choice as a carrier gas . However,its use requires special precautions as it can pose flammability hazards.

  • Adequate ventilation must be provided in storage area to prevent formation of combustible air- hydrogen mixtures
  • Hydrogen gas cylinders should be kept outside the laboratory in a covered shed to protect from sunlight and rain
  • All hydrogen couplings should be regularly checked for leaks
  • Most important before turning on hydrogen first ensure that the column is fitted inside the column oven and all connections are leak free otherwise hydrogen concentration can build up and explosions can result due to high temperature inside the oven
  • Before removing the column ensure that hydrogen supply has been turned off

Safe Handling of Gas Cylinders

  • Do not store cylinders in stairways, near the elevators or entrance to the laboratory
  • Compressed gas cylinders should be kept away from heat sources and in any case not subjected to temperatures exceeding 50°C
  • Gas cylinders should not be kept in the vicinity of combustibles, fuel oil or even empty waste paper cartons
  • Cylinders should be kept upright and fastened securely with a chain to the wall or a laboratory bench
  • Connecting gas lines should not cross passages to prevent damage or tripping by those who cross them. Wall mounting with proper colour coding is recommended
  • Cylinders should be moved after fastening inside hand held trolleys in vertical position and with safety caps fixed. Under no circumstances should cylinders be rolled on the floor
  • Always use regulators, hose connections and tubings which are approved by the equipment supplier
  •  A flashback arrestor must be used when working with flammable gases.(such as Hydrogen & Acetylene). In the event, a fire propagates through the hose the arrestor will stop the fire from reaching the tank.
  •  Never use oil orca grease on or around oxygen cylinders, valves, fittings or regulator as it may cause fire or explosion.
  • Cylinders with neck threads should have a cap in place over the valve. Remove the cap by hand. Never use a screwdriver, crowbar, or other leverage device to remove the cap
  • Read the cylinder label to confirm the gas received is the gas purchased. Never identify the product by the color of the cylinder.
  • It is equally essential to keep a regular check on pipes, hoses and connectors leading to the instrument. These should be free of kinks or damage. Perform regularly leak checks on all joints and seals
  • On completion of analysis close all cylinder valves and allow the residual gas to bleed before turning off the exhaust vent
  • Never keep empty and filled gas cylinders in same. areas
  • Do not store cylinders in spaces where they can come in contact with live wires as this can cause electric shocks.
  • Non compatible gases such as hydrogen and oxygen should not be stored in a common storage area as these can form explosive mixtures
  • Fire extinguishers should be provided in area storing combustible gases and these should be checked periodically

Gases do not pose major hazards when safety precautions are exercised. Always remember you are responsible for your safety and also safety of your laboratory co-workers.

Please do offer your suggestions and comments based on your personal experiences.

Acknowledgement:The author wishes to thank Mr Girish Kulkarni for his valuable inputs which have been included in the article.

About Dr. Deepak Bhanot

Dr Deepak Bhanot is a seasoned professional having nearly 30 years expertise beginning from sales and product support of analytical instruments. After completing his graduation and post graduation from Delhi University and IIT Delhi he went on to Loughborough University of Technology, UK for doctorate research in analytical chemistry. His mission is to develop training programs on analytical techniques and share his experiences with broad spectrum of users ranging from professionals engaged in analytical development and research as well as young enthusiasts fresh from academics who wish to embark upon a career in analytical industry.

Comments

  1. Girish Kulkarni says:

    Dear Dr. Deepak Bhanot

    This is very good Information. I want to add some more to it

    1. A flashback arrestor must be used when working with flammable gases.(such as Hydrogen & Acetylene). In the event, a fire propagates through the hose the arrestor will stop the fire from reaching the tank.
    2. Never use oil or grease on or around oxygen cylinders, valves, fittings or regulator as it may cause fire or explosion.
    3. Cylinders with neck threads should have a cap in place over the valve. Remove the cap by hand. Never use a screwdriver, crowbar, or other leverage device to remove the cap
    4.Read the cylinder label to confirm the gas received is the gas purchased. Never identify the product by the color of the cylinder.

    Thanks……..
    Girish Kulkarni.

    • Dear Girish,
      You appear to be a well informed and knowledgeable person.I would welcome you to contribute to the site by posting me short articles ,say400-500 words length which you feel will benefit the rest of our readers. The articles after approval will be published on the site under your name as guest contribution.In case you require any further details regarding the articles please feel free to contact me on my e-mail.
      Best regards
      Dr Deepak Bhanot

    • Many thanks again. We value your useful inputs and are pleased to inform that for the benefit of others the points suggested have been incorporated into the article

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