A new combination for the determination of ultratrace cadmium: solid-phase microextraction by stearic acid-coated magnetic nanoparticles prior to batch-type hydride generation atomic absorption spectrometry

Thiolated poly(aspartic acid)-functionalized two-dimensional MoS2, chitosan and bismuth film as a sensor platform for cadmium ion detection

In this work, a sensitive electrochemical platform for determination of cadmium ions (Cd²⁺) is obtained using thiolated poly(aspartic acid) (TPA)-functionalized MoS₂ as a sensor platform by differential pulse anodic stripping voltammetry (DPASV). The performance of the TPA–MoS₂-modified sensor is systemically studied. It demonstrates that the TPA–MoS₂ nanocomposite modified sensor exhibits superior analytical performance for Cd²⁺ over a linear range from 0.5 μg L⁻¹ to 50 μg L⁻¹, with a detection limit of 0.17 μg L⁻¹. Chitosan is able to form a continuous coating film on the surface of the GC electrode. The good sensing performance of the TPA–MoS₂-modified sensor may be attributed to the following factors: the large surface area of MoS₂ (603 m² g⁻¹), and the abundant thiol groups of TPA. Thus, the TPA–MoS₂-modified sensor proves to be a reliable and environmentally friendly tool for the effective monitoring of Cd²⁺ existing in aquacultural environments.

In this work, a sensitive electrochemical platform for determination of cadmium ions (Cd²⁺) is obtained using thiolated poly(aspartic acid) (TPA)-functionalized MoS₂ as a sensor platform by differential pulse anodic stripping voltammetry (DPASV).

Design of GO–Ag-functionalized Fe3O4@CS composite for magnetic adsorption of rhodamine B

In this study, a novel magnetic composite (Fe₃O₄@CS/GO/Ag) modified with chitosan (CS), graphene oxide (GO) and Ag nanoparticles (Ag NPs) was successfully prepared as an efficient adsorbent for detection of rhodamine B (RB) combined with a fluorescence technique. The properties of the magnetic composite were confirmed by field emission scanning electron microscopy, energy dispersive X-ray spectroscopy, and vibrating sample magnetometry. The components of Fe₃O₄@CS/GO/Ag endowed it with excellent extraction performance and convenient operation. The main parameters affecting extraction and desorption efficiency were all investigated systematically. Under the optimized experimental conditions, the proposed method showed linear ranges (0.2–6.0 μg L⁻¹) with R² = 0.9992. The limits of detection (LODs) and quantification (LOQs) were 0.05 and 0.2 μg L⁻¹ (n = 3), respectively. Fe₃O₄@CS/GO/Ag exhibited outstanding extraction efficiency for RB, compared with CS-coated Fe₃O₄ nanoparticles (Fe₃O₄@CS) and GO-modified Fe₃O₄@CS (Fe₃O₄@CS/GO). The applicability of the proposed method was investigated by analyzing four real samples (waste water, soft drink, shampoo, and red pencil) and the spiked recoveries ranged between 94% and 97% with RSD ranging from 3% to 6%, which showed that the proposed method had satisfactory practicability and operability.

A novel magnetic composite modified with chitosan, graphene oxide and Ag nanoparticles, was successfully prepared as an efficient adsorbent for detection of rhodamine B combining with fluorescence technique.