Cyclodextrin-functionalized magnetic graphene as solid-phase extraction absorbent coupled with flame atomic absorption spectrophotometry for determination of cadmium in water and food samples

A magnetic hydroxypropyl--cyclodextrin-functionalized reduced graphene oxide was synthesized and used as a magnetic solid-phase extraction adsorbent for the enrichment of cadmium from water and food samples before its determination by flame atomic absorption spectrometry. The effects of pH, amount of adsorbent, extraction time, desorption condition, and coexisting ions on the extraction efficiency were investigated and optimized. Under the optimal conditions, the limit of detection was 0.23 mu gL(-1) for water samples and 0.015 mu gg(-1) for food samples, respectively. The linear range was between 0.50 and 100.0 mu gL(-1) with a good correlation coefficient of 0.9986 in water samples, and between 0.050 and 5.0 mu gg(-1) with a correlation coefficient of 0.9975 in food samples. The method recoveries for the spiked samples were in the range of 87.5-102.4%, with the relative standard deviations ranging from 4.7% to 6.2% and enrichment factors ranging from 38 to 41, respectively. The adsorbent could be reused over 50 times without a significant change of extraction capability. The established method provides a promising environmentally friendly alternative for the determination of cadmium in complex matrix samples with no need of additional chelating reagents during the extraction process.