Helium and More Helium

May 17 was the 178th birthday of British astronomer Sir Joseph Norman Lockyer, one of the two people credited with discovering the element helium. Using electromagnetic spectroscopy, in 1868 Lockyer observed a yellow spectrum line near the edge of the Sun that could not be explained by any known material. He decided it must be caused by an unknown solar element, which he named after the Greek “Helios” for “sun.” (A similar observation was made the same year by French scientist Pierre Janssen, so both men are credited with the discovery.) Despite being the second-most abundant element in the universe, terrestrial helium was not identified until 10 years later. Today, helium is commonly used as a carrier gas in gas chromatography. Helium played a leading role in a novel technology innovation from Agilent. In 2009, the development team wanted to create a competitive advantage in Agilent’s GC/Triple Quadrupole Mass Spectrometers. Measurement sensitivity is the most important specification for a triple-quad, and the goal was to achieve a signal-to-noise ratio 10 times better than the competition. A major source of noise in GC/MS is caused by excited helium atoms, which cannot be removed by electromagnetic filters or lenses because they carry no charge. Instead of trying to remove the helium, the team found that adding additional helium into the collision cell actually reduced noise. By optimizing the flow, they achieved a 4x reduction in noise and achieved their goal. They solved the problem of helium with more helium! Helium quench was a simple and inexpensive innovation that enabled the Agilent 7000 Series QQQ GC/MS to become one of Agilent’s most successful product families.

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