Determination of Cadmium in Aqueous Solution by Liquid Glow Discharge-Atomic Emission Spectrometry

KeyWord:electrolyte cathode glow discharge(ELCAD)  liquid glow discharge(LGD)  plasma  atomic emission spectrometry(AES)  cadmium

Abstract:

      A new reactor termed as liquid glow discharge(LGD) was modified and designed according to the principle and characteristic of electrolyte cathode glow discharge(ELCAD) for the determination of cadmium in aqueous solution.The effects of discharge voltage and solution concentration on the discharge stability,signal strength,sensitivity and detection limit were investigated in detail.The detection limits of present work were compared with the values measured by ELCAD.The results showed that with the increase of discharge voltage from 600 V to 720 V,the electronic temperatures were increased from 2 000 K to 3 300 K,electron densities were decreased from 2.47¡Á1016 cm-3 to 1.77¡Á1016 cm-3,emission intensities were enhanced and the sensitivity of the method for cadmium was increased with limits of detection of 1.22-2.95 mg/L.All results demonstrated that the LGD-AES is a promising technique in detection of metal elements in aqueous soltion because of small size of discharge equipment,low energy consumption,high discharge stability,small background spectrum interference and high sensitivity.