alizarin dye based ultrasensitive plasmonic sers probefor trace level cadmium detection in drinking water
alizarin functionalized on plasmonic gold nanoparticle displays strong surface enhanced raman scatter-ing from the various raman modes of alizarin, which can be exploited in multiple ways for heavy metalsensing purposes. the present article reports a surface enhanced raman spectroscopy (sers) probe fortrace level cadmium in water samples. alizarin, a highly raman active dye was functionalized on plas-monic gold surface as a raman reporter, and then 3-mercaptopropionic acid, 2,6-pyridinedicarboxylicacid at ph 8.5 was immobilized on the surface of the nanoparticle for the selective coordination ofthe cd(ii). upon addition of cadmium, gold nanoparticle provide an excellent hotspot for alizarin dyeand raman signal enhancement. this plasmonic sers assay provided an excellent sensitivity for cad-mium detection from the drinking water samples. we achieved as low as 10 ppt sensitivity from variousdrinking water sources against other alkali and heavy metal ions. the developed sers probe is quitesimple and rapid with excellent repeatability and has great potential for prototype scale up for fieldapplication.
heavy metal contamination is a growing concern worldwide.cadmium is one of the most toxic elements and widely foundin fertilizers, fuel combustions, plastics toys and several otherindustrial products. according to the centers for disease con-trol and prevention (cdc), cadmium ranks seventh out of 275hazardous substances in the environment [1,2]. cadmium con-tamination is frequently found in jewelry and battery operatedtoys and paints. a recent investigation showed up to 90% of ele-mental cadmium in more than 100 jewelry items for kids invarious stores in texas, new york, california and ohio [3]. num-ber of methods have been developed to detect cadmium such asinductively coupled plasma mass spectrometry (icp-ms), atomicabsorption spectrometry (aas), electrochemical sensing, fluores-cence turn on and off sensing techniques [4–11]. among manypopular methods, fluorescence is a highly reliable and sensitivetechnique for metal detection. kubo et al. [12], has reported astrategy based on the behavior of phenylboronic acids (pbas) andalizarin meoh solution for the anion and cation sensing.
