Determination of cadmium by flame-atomic absorption spectrometry after separation and preconcentration by modified mesoporous silica materials

A type of modified mesoporous silica material MSN-PA was synthesized using propargyl amine by azide– alkyne cycloaddition and propargyl amine was used as the functional group. The material was characterized using Fourier transform infrared spectroscopy( FT-IR). A new method for the determinaon of trace cadmium was developed by fame atomic absorption spectrometry( FAAS) after separation / preconcentration with the modified mesoporous silica material as adsorbent. The results indicated that cadmium can be well absorbed under pH7.5 and the contact time was 30 min. After adsorption,the recovery( 95%) of metal ions was accomplished using 1 m L 1. 0 mol / L HNO_3 ethanol solution as an eluent,and determined by FAAS. The linear detectable range of cadmium ranged from 0. 5 ng / m L to 50 ng / m L. The limit of detections( LOD) was 0. 06 ng / m L,and enrichment factor of the present method was found out to be 50. The RSD( n = 20) for 20 ng / m L Cd~(2+) standard solution was 1. 9%. The spiked recoveries of Cd~(2+) were in the range of 95. 5% ~ 97. 5%. The modified mesoporous silica demonstrated excellent anti interference capacitor and the adsorption / desorption process remained effective for at least twenty consecutive cycles. The method was applied to the determination of trace Cd~(2+) in environmental water samples,and the results was satisfactory.