Analytical Sciences

Semi-Empirical Equation to Describe the Electron Number Density in the Analytical Zone of the ICP as Functions of the r.f. Power, Height above the Load Coil, Carrier Gas and Water Flow Rates

Susumu NAKAMURA

National Institute of Materials and Chemical Research, Higashi, Tsukuba 305-8565, Japan

This study presents a semi-empirical equation of the electron number density at the analytical zone of the Ar ICP. This equation was developed from data of a three-stage experiment which demonstrated that the electron number density linearly increased with an increase in the r.f. power, exponentially decreased with an increase in the height above the load coil, and decreased when the quantity of the carrier gas and water molecules increased. This behavior of the electron number density at the analytical zone can be explained by the following equation: n_e=k_pF[1-k₅A-k₆W]exp(-k_dx), where A=A₀(1-k₇F)exp(-k₈x) and W=W₀(1-k₉F)exp(-k₁₀x). (Keywords: ICP atomic emission spectrometry, empirical equation, electron number density, analytical zone, dry or wet)

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