ASTM D2650-10(R2021) pdf free download

ASTM D2650-10(R2021) pdf free download.Standard Test Method for Chemical Composition of Gases by Mass Spectrometry
1. Scope
1.1 This test method covers the quantitative analysis of gases containing specific combinations of the following com- ponents: hydrogen; hydrocarbons with up to six carbon atoms per molecule; carbon monoxide; carbon dioxide; mercaptans with one or two carbon atoms per molecule; hydrogen sulfide; and air (nitrogen, oxygen, and argon). This test method cannot be used for the determination of constituents present in amounts less than 0.1 mole %. Dimethylbutanes are assumed absent unless specifically sought. N OTE 1—Although experimental procedures described herein are uniform, calculation procedures vary with application. The following influences guide the selection of a particular calculation: qualitative mixture composition; minimum error due to components presumed absent; minimum cross interference between known components; maxi- mum sensitivity to known components; low frequency and complexity of calibration; and type of computing machinery. Because of these influences, a tabulation of calculation procedures recommended for stated applications is presented in Section 12 (Table 1). N OTE 2—This test method was developed on Consolidated Electrody- namics Corporation Type 103 Mass Spectrometers. Users of other instruments may have to modify operating parameters and the calibration procedure. 1.2 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard. 1.3 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appro- priate safety, health, and environmental practices and deter- mine the applicability ofregulatory limitations prior to use.1.4 This international standard was developed in accor- dance with internationally recognized principles on standard- ization established in the Decision on Principles for the Development of International Standards, Guides and Recom- mendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.
10. Calibration and Standardization
10.1 Apparatus—Determine whether operating conditions remain normal by making certain tests periodically, following instructions furnished by the manufacturer of the apparatus. Include in these tests rate of leak, ion-beam control settings, pattern reproducibility, and galvanometer calibrations. 10.1.1 To ascertain pattern stability, the following schedule is provided both for laboratories that have mass spectrometers with conventional temperature control and for laboratories that vary the temperature of the ionization chamber to obtain constant patterns: Run Number Compound 1 n-butane 2 n-butane 3 hydrogen 4 n-butane 5 hydrogen 10.1.2 If the 43/58 and 43/29 ratios of the first two runs do not agree with 0.8 %, further runs must be made until agree- ment is attained, either by adjusting the temperature of the ionization chamber or by other techniques commonly used by the laboratory. In any case, the three 43/58 and 43/29 ratios must agree within 0.8 % and the three butane sensitivities within 1 %. The two hydrogen sensitivities must agree within 1.5 %. A standard gas sample can also be used as an additional check. 10.2 Reference Standards—Check the entire range with the spectrometer evacuated. This check provides a blank or back- ground spectrum. If the approximate composition of the mixture is not known, make a preliminary run over the entire operating mass range. If the composition is known, the necessary calibrating gases should have been run recently enough before the mixture to preclude pattern changes. The calibrating gases should be run in order of decreasing molecu- lar weight. If isomers are present, do not run them in succession. Introduce the calibrating gases through the inlet system at a pressure closely approximating that used for the mixture spectrum. 10.2.1.1 Introduce sufficient sample into the evacuated inlet system to give 4 Pa to 6.7 Pa (30 mtorr to 60 mtorr) pressure in the expansion reservoir of the instrument. (Warning— Samples and reference mixtures are extremely flammable. Keep away from heat, sparks, and open flames. Use with adequate ventilation. Cylinders shall be supported at all times. Hydrocarbon vapors that may be vented shall be controlled to assure compliance with applicable safety and environmental regulations.)