Effect of magnetic field on the gas-jet boosted radio frequency glow discharge atomic emission spectrometry

Abstract

The effect of a magnetic field on the radio frequency (rf) powered gas-jet boosted glow discharge (GD) source was investigated. The fundamental characteristic study includes the effects of discharge power of 10–50 W, and pressures range from 2 to 7 torr, on dc bias potential, sample weight loss rate and emission intensity with and without magnetic field. The bias potential and sample weight loss do not change with pressure above approximately 4 torr; however, as the pressure is dropped below approximately 4 torr there is a significant decrease in the bias potential and sample weight loss with addition of the magnetic field, while significant enhancement in signal intensity was observed with the addition of magnetic fields using Cu samples at 40 W, 200 ml/min gas flow rate and 5 torr pressure. The Cu(I) 324.7-nm and Cu(I) 327.4-nm wavelengths were enhanced as much as three times, while one order of magnitude enhancement was observed at the Cu(II) 224.7-nm wavelength. These results show that a magnetic field in this system only enhanced the excitation of sputtered atoms, and not on the sputtering. Both magnetic and non-magnetic boosted rf-GD shows a short-term precision of <1% RSD and long-term stability of <5% RSD for both major and trace element lines. Calibration curves are linear over 3–4 orders of magnitude with a general improvement of linearity by ratioing the signal to an internal standard of the matrix in both systems. Limits of detection for magnetic boosted GD are tens part per billion from many trace elements in low alloy steel which is an order of improvement over conventional rf-GD system.