We present a novel chip-based device featuring a pinhole emitter for mass spectrometry (MS) coupling with integrated fluidic back-pressure regulation for supercritical mobile phases. This design enables facile coupling of packed capillary columns used for supercritical fluid chromatography (SFC) with atmospheric pressure ionization mass spectrometry. The monolithic microfluidic chips were fabricated using selective laser-induced etching, seamlessly integrating multiple functions, including comb-shaped particle retention structures for column packing and ports for zero-clearance connection with standard fused silica capillaries. The integrated restrictive pinhole MS emitter generated by dielectric breakdown is a key innovation of the micro SFC-MS platform. It enables a controlled decompression of the supercritical CO-based mobile phase within few micrometers to efficiently transfer the analytes from the compressed supercritical fluid into the ambient gas phase in front of the MS orifice. The inclusion of an arrowhead-shaped fluidic element further enables precise, dilution-free back-pressure regulation. With a minimal postcolumn volume of just 3 nL, the system shows excellent MS coupling performance, as demonstrated by rapid SFC-MS analysis of pharmaceuticals and natural products.
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http://dx.doi.org/10.1021/acs.analchem.4c05171 | DOI Listing |
Anal Chem
December 2024
Institute of Analytical Chemistry, Leipzig University, Linnéstraße 3, 04103 Leipzig, Germany.
We present a novel chip-based device featuring a pinhole emitter for mass spectrometry (MS) coupling with integrated fluidic back-pressure regulation for supercritical mobile phases. This design enables facile coupling of packed capillary columns used for supercritical fluid chromatography (SFC) with atmospheric pressure ionization mass spectrometry. The monolithic microfluidic chips were fabricated using selective laser-induced etching, seamlessly integrating multiple functions, including comb-shaped particle retention structures for column packing and ports for zero-clearance connection with standard fused silica capillaries.
View Article and Find Full Text PDFRev Sci Instrum
July 2024
Naval Research Laboratory, Washington, District of Columbia 20375, USA.
The use of an electron beam to pump an excimer laser has the advantage of being readily scalable to higher laser energies at high efficiency. Typically, a pulsed power driver generates the electron beam in a vacuum diode that consists of an electron emitter and a thin anode foil that holds the vacuum against the atmospheric-pressure laser gas. Even a miniscule leak in the anode foil can lead to an electrical breakdown in the vacuum diode, resulting in the destruction of the foil and evidence of the failure mechanism.
View Article and Find Full Text PDFBiophys Rep (N Y)
March 2024
Delft Center for Systems and Control, Delft University of Technology, Delft, the Netherlands.
Modulation enhanced single-molecule localization microscopy (meSMLM), where emitters are sparsely activated with sequentially applied patterned illumination, increases the localization precision over single-molecule localization microscopy (SMLM). The precision improvement of modulation enhanced SMLM is derived from retrieving the position of an emitter relative to individual illumination patterns, which adds to existing point spread function information from SMLM. Here, we introduce SpinFlux: modulation enhanced localization for spinning disk confocal microscopy.
View Article and Find Full Text PDFSci Adv
December 2023
Department of Electrical Engineering and Computer Sciences, University of California, Berkeley, CA 94720, USA.
The mid-wave infrared (MWIR), ranging from 2 to 5 micrometers, is of substantial interest for chemical sensing, imaging, and spectroscopy. Black phosphorus (bP)-based MWIR light emitters and detectors have been shown to outperform the state-of-the-art for commercial devices due to the low Auger recombination coefficient of bP. However, the scalability of these devices remains a challenge.
View Article and Find Full Text PDFPhys Med Biol
March 2023
MILabs BV, Houten, The Netherlands.
Microscopic nuclear imaging down to spatial resolutions of a few hundred microns can already be achieved using low-energy gamma emitters (e.g.I, ∼30 keV) and a basic single micro-pinhole gamma camera.
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