Quartz tube orifice leaks for local, fast-response gas sampling to mass spectrometers

Abstract

Simple and versatile quartz tube orifice leaks, suitable for sampling of gas mixtures to mass spectrometers, have been made by heating the tip of a quartz tube in a hydrogen-oxygen flame. With these leaks the requirement of expensive and clumsy differential pumping stages is removed. The quartz probes have been used in gas sampling from catalytic reaction cells at 1 atm to a mass spectrometer. The sampling position can be located within 0.1 mm from the catalyst. Continuous recording of the local gas composition is then achieved with a response time of about 0.05 s, and with a minimum perturbation of the gas flow. The probes have been used in ambient air and at temperatures around 1000 K for extended periods of time without deterioration or plugging. The high stability at elevated temperatures and chemical resistance seem to make these probes useful for various applications, e.g., in sampling from combustion flames. The gas flow through the leak is determined by a very short and narrow constriction at the tube tip. In a leak with a throughput of 1x10(-4) Torr l/s at 1 atm inlet pressure, the constriction has a diameter of 5-7x10(-4) cm and a length of about 0.015. cm.

The sticking probability of hydrogen on Ni, Pd and Pt at a hydrogen pressure of 1 bar

“…The gas is sampled with a quartz capillary, made from a 1 mm o.d. quartz tube [39]. The quartz tube is mounted concentrically in the gas inlet nozzle, see figure 1, and gas is blown toward the sample surface through the annulus between the capillary and the nozzle.…”

The Ligand Effect: CO Desorption from Pt/Ru Catalysts

“…open circuit mode with pure argon flow on the cathode side. The gas content was probed on the anode outlet using a quartz tube sniffer connected to a mass spectrometer [25]. The gas dosing system allowed for fast interchange between varieties of different gases.…”

Microsystem with integrated capillary leak to mass spectrometer for high sensitivity temperature programmed desorption

“…In Ref. 4 this is done by placing a narrow quartz capillary leak 5 in the outlet channel on the chip. In the present work, the capillary leak is fabricated directly in the silicon structure.…”