Multidimensional Mass Spectrometry of Multicomponent Nonionic Surfactant Blends.

Ultraperformance liquid chromatography (UPLC) and ion mobility (IM) spectrometry were interfaced with mass spectrometry (MS) and tandem mass spectrometry (MS/MS) to characterize a complex nonionic surfactant mixture. The surfactant was composed of a glycerol core, functionalized with poly(ethylene oxide) units (PEOn) that were partially esterified by caprylic and/or capric acid. Reversed-phase UPLC classified the blend based on polarity into four groups of eluates, corresponding to compounds with zero, one, two, or three fatty acid residues. Additional separation within each eluate group was achieved according to the length of the fatty acid chains. Coeluting molecules of similar polarity were dispersed in the gas phase by their collision cross section in the IM dimension. Performed in series, UPLC and IM allowed for the separation and detection of several isomeric and isobaric blend constituents, thereby enabling their isolation for conclusive MS/MS analysis to confirm or elucidate their primary structures and architectures (overall four-dimensional, 4D, characterization).

The Oxygen Cost of a 20-Minute Steady-State Jog for High School Boys and Girls.

This study evaluated the aerobic demands of the 20-minute steady-state jogging speeds for 15 high school students. All subjects performed a discontinuous treadmill test that included submaximal speeds, the Fit Youth Today criterion referenced speeds, and finally a run to voluntary fatigue. Stages lasted 5 minutes. Preliminary data indicated that both groups averaged between 87% (the 9 boys) and 93% (the 6 girls) of their respective peak oxygen consumption at the criterion referenced speeds during treadmill testing. According to the American College of Sports Medicine guidelines for healthy adults, these intensities represent the upper threshold for aerobic conditioning, and high exercise intensities can increase the risk of injury. Although the results of this study are preliminary in nature and based on a small sample size, we suggest that the criterion referenced distances (speeds) for the FYT 20-minute steady-state jog may need modification.