Performance of a nitrogen dioxide permeation device

Sulfur trioxide permeation tube for calibration of sulfuric acid measurement methods

“…The observed temperature aging or conditioning effect was noted in earlier studies at Brookhaven for N02 permeation devices (19) and had been observed in work at the National Bureau of Standards (20)(21)(22). Once aged by temperature cycling, the repeatability of Brookhaven N02 permeation devices (19, 23) was generally better than ±1%.…”

Determination of nitrogen dioxide in air-compressed gas mixtures by quantitative tunable diode laser absorption spectrometry and chemiluminescence detection

“…Second harmonic measurements were carried out by simultaneously superimposing a 5-8 kHz sine wave, from an external waveform generator, on the diode laser tuning current. A lock-in amplifier referenced to this frequency was used to synchronously detect the second harmonic signal (10)(11)(12)(13)(14)(15)(16) of the frequency-modulated absorption. In these measurements the diode beam was not chopped, and initially, as with preliminary direct absorption measurements, we employed the technique of slow scan integration.…”

“…N02 Permeation Calibration System. A series of all-Tefion permeation tubes, approximately 10 cm long, were prepared in accordance with recommended procedures (15) at various times throughout this study and maintained at constant temperature to within ±0.01 °C in a thermostated condenser. At temperatures between 20 and 30 °C, various combinations of tubes and flow rates produced N02 concentrations ranging from 10 ppm up to 832 ppm.…”

Laser photoacoustic detection of nitrogen dioxide in the gas-phase titration of nitric oxide with ozone

“…Known N02 concentrations, [N02]permeat¡on, were generated in this study by varying the diluent air flow passing over a calibrated N02 permeation tube. The permeation rate of this tube was calibrated on a weekly basis according to recommended procedures (12), The diluent air flow was measured upstream of the permeation tube with a calibrated mass flow meter, Hastings Model ALL-IK, and checked periodically at a flow measurement port located at the calibration system outlet as indicated in Figure 2.…”