Basic characteristics in the determination of cadmium by metastable transfer emission spectroscopy with a tungsten coil atomizer

A metastable transfer emission spectroscopy (MTES) combined with a tungsten coil atomizer was carried out for the sensitive determination of cadmium. Pulse atomization induced by a capacitor discharge to the coil atomizer pro duced a condensed vapour, which was transported and mixed with active nitro gen in a metastable state produced by a microwave discharge. A high sensiti vity was obtained from the emission of cadmium by this system. Some new spe ctra were observed by MTES. Five mu l of a cadmium solution acidified with nitric acid was deposited on the coil atomizer. A detection limit of less t han 5 pg was obtained at a wavelength of 326.1 nm. This system is more sens itive by a factor of six than a system using a Ta boat. The linearity range of a calibration curve was from 5 to 200 pg Cd, beyond which the emission signal intensity was saturated. The saturation is likely to be controlled b y the density of metastable nitrogen molecules existing in the excitation r egion.