Assessing the Impact of Drift Gas Polarizability in Polyatomic Ion Mobility Experiments

Our latest manuscript was just accepted in Analytical Chemistry. We use a set of standards to discuss the implications of mixing drift gases for ion mobility experiments. We discuss if Blanc’s Law applies to polyatomic ions. We also address the assumptions made by Asbury and Hill (Anal. Chem. 2000, 72 (3), 580– 584, DOI: 10.1021/ac9908952) that… Continue reading

Validation of Calibration Parameters for Trapped Ion Mobility Spectrometry

While trapped ion mobility spectrometry (TIMS) provides excellent separation capability as an ion mobility technique, one major drawback is the need for a calibration step to convert drift times into a reduced mobility value (K0). The calibration step, therefore, requires accurate reference mobilities of IMS standards. With this work, recently… Continue reading

Organophosphorus Proton Affinities from AFT-MS and Kinetic Method with Computational Values

After applying the atmospheric flow tube-mass spectrometry approach to ambient vapor detection of phosphonic acids and tributyl phosphate, we observed that few organophosphorus compounds have reported proton affinities in the literature. Phosphonate species that are structurally similar to chemical warfare agent simulants in particular are valuable to characterize, which is… Continue reading

Recent Publication: Mobility Separation and UVPD of Co-Adducted Tetrasaccharides

Ultraviolet photodissociation (UVPD) has had its application directed primarily at biomolecule analysis, but with a common drawback of low fragment abundances. We encountered this same problem with UVPD of two sodiated isomeric glycans, but found a significantly higher fragment yield from the cobalt adducts of those same tetrasaccharides. An additional… Continue reading

IMS – Ion Trap Equipped with UV Photofragmentation

  In early 2015 the research group is pleased to bring the next generation ion mobility-ion trap system online.  This system is equipped with two ion gates which allows the speed of the IMS to be effectively coupled to the slow scan speeds of traditional ion trapping experiments.  Though not… Continue reading

Venn Diagram Widgets

Generally, it is recommended to avoid qualitative measures when quantitative solutions exist.  However, if the genuine need arises here are a list of useful Venn diagram widgets that may be found online: Quite Powerful: Simple Solution: Downloadable: Continue reading

We Have Ignition on Ion Engine #1

The Clowers Research Group is now live.  Reporting in are the background ions from ionized air measured using a residual quadrupole gas analyzer and the LeCroy “Panzer” oscilloscope.  These data are to help monitor background gases in the high vacuum chamber (not shown) and provide diagnostic support for gases ionized… Continue reading

PCB Tools and Gerber Viewer

Though seemingly outside the realm of chemistry, electronics lie at the heart of many experimental disciplines as all rely ability to make accurate and reproducible measurements.  An unfortunate byproduct of this requirements is often the reliance on outside sources–just look at your oscilloscope should there be any questions.  In an… Continue reading

Useful Links

Duviz: command line tool for disk usage visualization: is a simple UNIX command line utility written in Python to visualize disk space usage. See it in action here:. I started writing it a couple of years ago (2009 according to the git commit log), but I just recently decided to make it more public. –

John Hunter Memorial Fund: John Hunter, author of Matplotlib, founding board member of NumFOCUS, husband to Miriam, and father to three daughters: Clara, Ava, and Rahel, was diagnosed with cancer in late July 2012 after returning from his keynote address at SciPy in Austin, TX. –

tangle: Tangle is a JavaScript library for creating reactive documents. Your readers can interactively explore possibilities, play with parameters, and see the document update immediately. Tangle is super-simple and easy to learn. This is a simple reactive document. –