Preliminary characterization of a low-powered microwave induced flame plasma for direct organic solvent nebulization

A low powered (90 W) microwave-induced plasma has been generated at atmospheric pressure by using a Beenakker cavity, a laboratory constructed torch, and a gas mixture of argon (400 ml/min), hydrogen (100 ml/min), and air (130 ml/min). This plasma has an excitation temperature of 3300–3500 K, electron number density of 7 × 1014 cm−3, and easily accepts direct methanol and ethanol introduction with a 1 ml/min solution nebulization rate. Detection limits (3σ) obtained from the atomic emission signals of Li, Sr, and Cr in water are 15, 120, and 290 ng/ml, respectively. Similarly, detection limits for the metals in methanol are 15, 120, and 260 ng/ml, respectively, and in ethanol they are 25, 360, and 330 ng/ml, respectively. The linear dynamic range is greater than three orders of magnitude.