Mass Spectrometry & Spectroscopy

  • Signal-to-Noise Spec Replaced with Instrument Detection Limit for Triple Quadrupole GC/MS

Signal-to-Noise Spec Replaced with Instrument Detection Limit for Triple Quadrupole GC/MS

Feb 20 2012 Read 1701 Times

Agilent Technologies, Inc announced that it is replacing the signal-to-noise specification with a new instrument detection limit specification for its 7000B triple quadrupole gas chromatography/mass spectrometry system. “Twenty or even 10 years ago, signal-to-noise was a reasonable indicator of GC/MS performance,” said Terry Sheehan, PhD, Agilent GC/MS Marketing Manager, “But GC/MS/MS baseline noise for simple standards is often too low and too inconsistent to be meaningful. Selection of different baseline segments can change the signal-to-noise ratio by five or even tenfold. Our new specification, the instrument detection limit, is based on the system’s precision, and precision directly correlates with ion count – the real measure of MS sensitivity.” Agilent considers IDL a better measure of GC/MS/MS performance because it follows the guidelines of the International Union of Pure and Applied Chemistry, the United States Environmental Protection Agency and many other organisations. IDL calculates typical
performance from a series of automated injections for an accurate view of system performance. The well-established Student’s t-test is applied to eight consecutive injections of 100 fg OFN using a 99% confidence interval. Additionally, the IDL specification confirms the performance of every component in the GC/MS/MS system, from the autosampler through the detector. The IDL specification of the Agilent 7000B GC/MS/MS system in EI mode is 12 fg OFN.“Dividing the MS signal of OFN standards by a noise value approaching zero gives a signal-to-noise ratio in the thousands, but that has no correlation to the system’s true performance,” Sheehan said. “It is time for ultra-low noise MS systems to use statistical detection criteria that are similar to the statistics that MS operators use for their methods.”

Reader comments

Do you like or dislike what you have read? Why not post a comment to tell others / the manufacturer and our Editor what you think. To leave comments please complete the form below. Providing the content is approved, your comment will be on screen in less than 24 hours. Leaving comments on product information and articles can assist with future editorial and article content. Post questions, thoughts or simply whether you like the content.

Post a Comment




Digital Edition

International Labmate November 2019

November 2019

In This Edition Articles - Translating Proteomic MALDi Tissue Typing to Clinical Pathology - Fusion Protein Complexes Analysed by CG-MALS - The Separation and Purification of Glutamine Deri...

View all digital editions

Events

Miconex

Nov 25 2019 Beijing, China

IFAT India

Dec 05 2019 New Delhi, India

Nepal Lab

Dec 13 2019 Kathmandu, Nepal

SLAS 2020

Jan 25 2020 San Diego, CA, USA

Arab Health

Jan 27 2020 Dubai, UAE

View all events