Articles and Applications
Alcohol consumption can seriously affect the ability of a driver to operate a vehicle and blood alcohol content (BAC) directly correlates with this impairment. A number of nations have zero alcohol tolerance for motorists, but the majority of countries worldwide have a limit of between 50 and 80 mg alcohol per 100 ml blood, or 0.05-0.08%. Results are used in court to provide quantitive levels of BAC, which makes it one of the most commonly practised analyses in forensic laboratories. The large number of samples and requirement for speed of sample processing mean that analysis needs to be conducted quickly, whilst giving reliable and accurate results.
Although there is now less concern about its availability, the price of helium is set to continue to increase meaning that cost-effective alternatives are still attractive to analytical labs.
Changing carrier gas from helium to hydrogen does not always present an opportunity for faster sample analysis. Method revalidation can be simplified by keeping the new method as close to the old method as possible, which will limit changes to sample selectivity and resolution whilst maintaining the retention times of analytes.
Summary Labs worldwide have recently found that helium has been in short supply, leaving a number of labs without carrier gas. Added to this, helium prices have doubled over the past 10 years causing a number of labs to look into alternative carrier gases for GC, such as nitrogen and hydrogen. As well as lower price and unlimited availability, hydrogen has a number of potential advantages over helium, including potential for faster throughput, improved chromatography and better sample resolution.
Helium is well known as Helium that makes balloons and airships float and in its liquid form, Helium is used in a variety of applications including cooling for magnets in Magnetic Resonance Imaging (MRI) scanners, cooling infrared detectors, and as a superconductor coolant in the large hadron collider at CERN.