Packaging and storage— Preserve in cylinders or in a low-pressure collecting tank.

Labeling— Where it is piped directly from the collecting tank to the point of use,label each outlet “Nitrogen 97Percent.”

Identification— The flame of a burning wood splinter is extinguished when inserted into a test tube filled with Nitrogen 97Percent.[NOTE—Exercise caution.]

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±50mLthrough 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±50mLthrough a carbon monoxide detector tube at the rate specified for the tube:the indicator change corresponds to not more than 0.001%.

Sulfur dioxide— Pass 1000±50mLthrough a sulfur dioxide detector tube at the rate specified for the tube:the indicator change corresponds to not more than 5ppm.

Limit of nitric oxide and nitrogen dioxide— Pass 500±50mLthrough a nitric oxide-nitrogen dioxide detector tube at the rate specified for the tube:the indicator change corresponds to not more than 2.5ppm.

Limit of oxygen— Not more than 3.0%of oxygen is present,determined as directed in the Assay.

Assay— Proceed with Nitrogen 97Percent as directed in the Assayfor Nitrogen.The peak response produced by the assay specimen exhibits a retention time corresponding to that produced by an oxygen-helium certified standard (see under Reagentsin the section Reagents,Indicators,and Solutions)and is equivalent to not more than 3.0%of oxygen when compared to the peak response of the oxygen-helium certified standard,indicating not less than 97.0%,by volume,of N2.

Expert Committee:(AER)Aerosols

USP28–NF23Page 3041

Phone Number:1-301-816-8269