China 
Africa 
Explore chapters and articles related to this topic
In Pursuit of Total Exposure Health
Published in Kirk A. Phillips, Dirk P. Yamamoto, LeeAnn Racz, Total Exposure Health, 2020
A relatively new and appealing technique for enhancing single-cell analysis methods is the incorporation of ion mobility spectrometry (IMS) with MS (Metz et al. 2017). This technique offers an improved identification of metabolites and provides an alternative to the solution-phase methods since separations are performed on the order of milliseconds in IMS, while on the order of minutes to hours in the conventional chromatographic methods. However, the potential of this integration has been hampered by the loss of sensitivity and the mismatched duty cycles traditionally associated with IMS/MS combination systems. Scientists at Pacific Northwest National Laboratory (PNNL) have developed an integrated instrument platform that overcomes these issues (PNNL 2020). The specific platform increases sensitivity and throughput by incorporating three distinct innovations: (1) an ion funnel technology, (2) ion funnel trap advancements that provide ion accumulation and precise release, and (3) a multiplexing feature for greater sensitivity with better-aligned duty cycles. The greater sensitivity derives from the technique yielding a higher signal-to-noise ratio than that produced by the conventional techniques. The new technique also increases analysis throughput because it allows ion packets to travel simultaneously through the drift region of the MS detector (PNNL 2020). Industry has further advanced the ion funnel technology by putting it on printed circuit boards, making the technology more economical. Structures for Lossless Ion Manipulations, or SLIM technology, can revolutionize the game of molecular and, more specifically, metabolomics studies. SLIM adds significant length—15, 20, 60 meters and more—into the typical ion path of a detector by implementing a serpentine pathway into the compactness of a small circuit board. Because the resolution of ion separations depends on the length of the drift path, the longer paths offered by SLIM provide more separation, grouping, and molecular analysis. Its developers think SLIM will “allow for a whole new universe of compounds and materials to be synthesized, purified, and collected” (PNNL 2017).
V-shaped ion funnel proton transfer reaction mass spectrometry
Published in Instrumentation Science & Technology, 2019
Yujie Wang, Kexiu Dong, Yannan Chu
In PTR-MS, the important function of the drift tube as the reaction chamber is to generate product ions, which are formed by proton transfer reaction of the H3O+ reagent ions with the VOCs, and to transmit product ions through a small aperture into the mass spectrometer. In recent years, a novel drift tube with a U-shaped ion funnel (IF) has been developed with increased sensitivity.[12–14] This approach was inspired by the initial IF used in the same pressure range in the 1990s.[15–17] The direct current (DC) and radio frequency (RF) electric fields in the IF are coupled to effectively radially focus and transmit ions in the drift tube. The reported improvements in detectable sensitivity are 1 to 2 orders of magnitude.[12,14]