title: Determination of gaseous nitrogen in gas mixtures using low pressure microwave induced plasma emission spectrometry.
abstract: A microwave induced plasma emission spectrometer operating at low energy (30 W) and low plasma gas pressure (2.5.10(-2) Pa) has been used for the quantitative measurement of molecular nitrogen in natural gases. The samples have been introduced into the plasma using a counterflow principle to produce emission spectra of diatomic molecular fragments in low excitation states (advantage: minimized interferences). The N(2) concentration has been determined by measuring the intensity of the N(2)-line at 337.13 nm (C(3)Pi(u)-B(3)Pi(g)-system; (0,0)vibrational transition) and of the NH-line at 336.03 nm (A(3)Pi(i)-X(2)Sigma(-)-system; (0,0)-vibrational transition). A linear correlation between concentration and signal intensities has been obtained in the range of 0.00% to 14.24% (v/v). The method possesses a detection limit of 0.01 ppm (v/v) for the determination of N(2), and a reproducibility of 1.33% (RSD).
authors.affiliation: Department of Instrumental Analytical Chemistry, Gerhard-Mercator-University of Duisburg, Lothar-Strasse 1, D-47057, Duisburg, Germany.
authors.forename: E
authors.initials: E
authors.lastname: Denkhaus
authors.forename: A
authors.initials: A
authors.lastname: Golloch
authors.forename: H M
authors.initials: HM
authors.lastname: Kuss