On-line Pre-Concentration and Separation of Inorganic Arsenic Based on Nano Platinum-Multiwall Carbon Nanotubes

On-line solid phase extraction (SPE) based on  nano adsorbent for pre-concentration of inorganic arsenic in water and waste water samples was developed prior to determine by hydride generation atomic absorption spectrometry (HG-AAS). By hydride generation simulation system (HGSS), the  inorganic arsenic in liquid samples changed to hydride form and pass through nano platinum multi wall carbon nanotube (3 wt % Pt, NPt-MWCNT,). The hydride form of arsenic (AsH3), pre-concentrated on NPt-MWCNTs and then completely desorption by electric heater accessory at 200oC for determining. The detection limit (LOD) and linear range of perposed method were obtained 0.4 ng L-1 and 6 –410 ng L-1 respectively(R2 = 0.9988). The relative standard deviations (%RSD) at 100 ng L-1 of analyte were found less than 5%. The capacity and efficiency  of nano adsorbent were 75 mg g-1 and 96% at  argon flow rate less than 100 ml min-1. The developed method was applied successfully to determination of ultra trace of inorganic arsenic in environmental samples by HG-AAS.