1. Gas Source
Helium is becoming increasingly expensive with reports of its price having doubled in some regions between 2013 and 2015. Added to its increased price, supply cannot be ensured in certain regions which is increasing the number of labs looking to change to hydrogen. Hydrogen generator: A hydrogen generator providing carrier grade hydrogen (99.9999%) such as the Peak Scientific Precision Hydrogen Trace is recommended as a safe source of hydrogen that will ensure prolonged column life and the highest quality of analysis. Supply tubing: Supply of hydrogen should be provided through new stainless steel or analytical grade copper tubing. It is important to change the tubing that was previously used to supply helium to the GC, since over time, deposits can build up on the inside of the tubing which hydrogen will strip out, causing higher background signal for a longer period of time.
2. Hydrogen Safety
Safe use of hydrogen: Since Hydrogen is an explosive gas, it is essential that health and safety in the lab is not compromised and many labs will have restrictions on the use of hydrogen cylinders in the lab. LEL: The lower explosive level (LEL) of hydrogen is 4% in air. Therefore a leak of hydrogen from a cylinder containing around 8000L hydrogen into a well vented laboratory has the potential to reach the LEL very quickly without warning and could create an explosive atmosphere. Added to concerns about large gas leaks, is the cumbersome nature of cylinders which must be moved when replaced, again posing a potential health and safety hazard. Gas Generator: A Peak Scientific Precision hydrogen generator is an ideal source of hydrogen gas, capable of supplying multiple GCs with UHP hydrogen for carrier gas and detector gas, whilst containing a very low volume of gas (less than 0.3L) at a low pressure. Precision hydrogen generators have a number of safety features that will detect any internal or external leaks between the generator and GC and will shut down the generator accordingly. Leak detector: Peak also offer an in-oven hydrogen detector that will shut down the generator if a significant hydrogen leak is detected within the GC oven.
3. Hardware
It is important to check the recommendations from your GC manufacturer regarding use of hydrogen carrier gas in your GC. Each manufacturer will have tested their GCs for use with hydrogen and may have specific recommendations depending on the model that you are using. Hardware changes, if required, are most likely to need to be made on GC-MS systems. Vacuum Pump: If you are using a GC-MS, it is important to ensure that your vacuum pump is efficient enough to maintain the vacuum in the source. Pumping efficiency is reduced for lighter molecules, so check the guidelines from your GC manufacturer to ensure that your pumping system can cope with hydrogen carrier gas. If you are purchasing a new GCMS system, make your supplier aware that you plan to use hydrogen carrier gas so that the correct vacuum pump is supplied. Ion Source: Depending on the manufacturer of your GC-MS, it is possible to get hydrogen upgrade kits, or replacement components for the ion source which will improve sensitivity when using hydrogen carrier gas for analysis of certain compounds. If you are purchasing a new GC-MS system, consult your supplier regarding which ion source will be supplied with the GC-MS to avoid extra cost and downtime at a later date.
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