Packaging and storage—
Preserve in cylinders or in a pressurized storage tank. Containers used for Oxygen must not be treated with any toxic, sleep-inducing, or narcosis-producing compounds, and must not be treated with any compound that will be irritating to the respiratory tract when the Oxygen is used.
NOTE—Reduce the container pressure by means of a regulator. Measure the gases with a gas volume meter downstream from the detector tube in order to minimize contamination or change of the specimens.
Labeling—
Label it to indicate whether or not it has been produced by the air-liquefaction process. Where it is piped directly from the cylinder or storage tank to the point of use, label each outlet “Oxygen.”
[NOTE—The various detector tubes called for in the respective tests are listed under
Reagents in the section
Reagents, Indicators, and Solutions.]
Identification—
A:
When tested as directed in the
Assay, not more than 1.0 mL of gas remains.
B:
Pass 100 ± 5 mL released from the vapor phase of the contents of the Oxygen container through a carbon dioxide detector tube at the rate specified for the tube: no color change is observed (distinction from carbon dioxide).
Odor—
Carefully open the container valve to produce a moderate flow of gas. Do not direct the gas stream toward the face, but deflect a portion of the stream toward the nose: no appreciable odor is discernible.
Carbon dioxide—
Pass 1000 ± 50 mL through a carbon dioxide detector tube at the rate specified for the tube: the indicator change corresponds to not more than 0.03%.
Carbon monoxide—
Pass 1000 ± 50 mL through a carbon monoxide detector tube at the rate specified for the tube: the indicator change corresponds to not more than 0.001%.
Assay—
Place a sufficient quantity of ammonium chloride–ammonium hydroxide solution, prepared by mixing equal volumes of water and ammonium hydroxide and saturating with ammonium chloride at room temperature, in a test apparatus composed of a calibrated 100-mL buret, provided with a two-way stopcock, a gas absorption pipet, and a leveling bulb, both of suitable capacity and all suitably interconnected. Fill the gas absorption pipet with metallic copper in the form of wire coils, wire mesh, or other suitable configuration. Eliminate all gas bubbles from the liquid in the test apparatus. Activate the test solution by performing two or three tests that are not for record purposes. Fill the calibrated buret, all interconnecting tubing, both stopcock openings, and the intake tube with liquid. Draw 100.0 mL of Oxygen into the buret by lowering the leveling bulb. Open the stopcock to the absorption pipet, and force the Oxygen into the absorption pipet by raising the leveling bulb. Agitate the pipet to provide frequent and intimate contact of the liquid, gas, and copper. Continue agitation until no further diminution in volume occurs. Draw the residual gas back into the calibrated buret, and measure its volume: not more than 1.0 mL of gas remains.
