Ideally speaking, carrier gas is defined as the inert gas that stays non-reactive with sample element. Today, mostly hydrogen, helium and nitrogen are widely used as carrier gas in chromatography. Each gas bears its own set of benefits and minuses. Though nitrogen has the most superior efficiency, but the linear velocity is low and narrow. Mostly common ones used are helium and hydrogen.
Helium is an expensive option and hydrogen has the fastest analysis time. So in recent times, trends show gradual conversion of helium gas over hydrogen. Let’s see what are the essential steps to change carrier gas from helium to hydrogen. Hydrogen is an enormously convenient carrier gas for gas chromatography and offers a number of significant merits equated to the usage of helium or nitrogen. The prime benefit of hydrogen is the circumstance that it can aim to a theatrical decrease of the time necessary for a given exit. As the use of hydrogen offers a notable drop in the time for separation, the analyst could also minimise the column temperature for discrimination. Helium is becoming progressively costly with reports of its price having amplified manifold in some places in between the year 2013 and 2015. Added to its enhanced price, supply can’t be guaranteed in certain places which is galloping the number of labs exploring to switch to hydrogen.
Source of hydrogen should be delivered through brand new stainless steel or systematic grade copper tubing. It is significant to convert the tubing that was formerly used to source helium to the gas chromatography, over prolonged time, residues can build up on the interior of the tube which hydrogen will shred out, generating higher background signal for a lengthier period of time.
Hydrogen, can be functional over a wide range of rectilinear velocities while upholding a low height corresponding to a theoretical plate or HETP. This empowers the utilisation of a linear velocity greater than ideal with minimum fall in competence, ensuing in lesser analysis times.
While switching from helium to hydrogen, it is imperative to ensure lab safety. As Hydrogen is an explosive gas, it is indispensable that health and security in the lab is not negotiated and many labs will have limitations on the utilisation of hydrogen cylinders in the premises.
Another step in switching is checking the hardware. It is vital to double check the endorsements from the GC producer concerning use of hydrogen carrier gas in the GC. Each producer will have examined their GCs for application with hydrogen and may have specific commendations liable on the prototype that one is using.
Hardware changes, if desired, are most likely required to be constructed on GC-MS network. When setting up a new GC network with hydrogen carrier gas, one will require to nurture the column. Safeguard that the terminal of the column is outdoor the GC oven when one conditions the column to check and guard a build-up of hydrogen inside the GC oven as this could extant a threat of blast.