Glutathione Modified Ordered Mesoporous Carbon for Separation and Preconcentration of Trace Cadmium / 分析化学

ABSTRACT

A new derivative of ordered mesoporous carbon (GSH-CMK-3) has been prepared by chemical modification and functionalization of ordered mesoporous carbon with glutathione. The composite was fully characterized by means of Fourier transforming infrared spectroscopy (FT-IR), scanning electron microscope (SEM) image and thermogravimetric analysis (TGA). GSH-CMK-3 showed favorable chemical stability, thermal stability and excellent adsorption performance toward Cd2+and a maximum adsorption capacity of 87.87 mg/g was achieved. The adsorption kinetic follows pseudo-second-order adsorption model. In a sequential injection mini-column separation system, 0. 006 mol/L sulfourea (in 0. 2 mol/L HNO3) was adopted as eluent and the elution efficiency was 96%. With a sample volume of 1000 μL and 50 μL of eluate, an enrichment factor of 17.3 was obtained. A procedure for on-line selective separation and preconcentration of trace Cd2+was developed by graphite furnace atomic absorption spectrometry. Along with a detection limit of 1.9 ng/L (n=7,3σ) and a linear range of 0.05-0.20 μg/L, a RSD of 2.9% (n=13,100 ng/L) was achieved. The method was validated by analyzing Cd2+in a certified reference material GBW08608.