An electrochemiluminescence immunosensor based on signal magnification of luminol using OER-activated NiFe2O4@C@CeO2/Au as effective co-reaction accelerator.

In this work, a novel, label-free electrochemiluminescence (ECL) immunosensor was constructed for the ultrasensitive detection of carbohydrate antigen 15-3 (CA15-3) by the combined use of NiFe2O4@C@CeO2/Au hexahedral microbox and luminol luminophore. The synthesis of the co-reaction accelerator (NiFe2O4@C@CeO2/Au) was related to the calcination of FeNi-based metal-organic framework (MOF), as well as the ingrowth of CeO2 nanoparticles and modification of Au nanoparticles. To be specific, the electrical conductivity will be boosted due to the Au nanoparticles, the synergetic effect generated between CeO2 and calcination FeNi-MOF could offer better activity of oxygen evolution reaction (OER). Herein, the NiFe2O4@C@CeO2/Au hexahedral microbox as a co-reaction accelerator has excellent OER activity and production of reactive oxygen species (ROS), thus increasing the ECL intensity of luminol in a neutral medium without other co-reactants such as H2O2. Because of these benefits, the constructed ECL immunosensor was applied to detect CA15-3 as an example under optimum conditions, the designed ECL immunosensor exhibited high-level selectivity and sensitivity for CA15-3 biomarker within a linear response range of 0.01-100 U mL-1 and an ultralow detection limit of 0.545 mU mL-1 (S/N = 3), demonstrating its potentially valuable application in the area of clinical analysis.

A sensitive electrochemiluminescence immunosensor for the detection of CA15-3 based on CeO2/Pt/rGO as a novel co-reaction accelerator.

In this work, we successfully constructed a label-free electrochemiluminescence (ECL) immunosensor for the detection of breast cancer marker antigen (CA15-3). In particular, 3,4,9,10-perylenetetracarboxylic acid (PTCA) is cleverly attached to the surface of silica spheres as a luminophore (NH2-SiO2-PTCA), which greatly alleviates the disadvantage of PTCA anti-induced aggregated luminescence and improves the ECL performance. Furthermore, Pt nanoparticles were used to dope CeO2 and introducing reduced graphene oxide (rGO) to prepare CeO2/Pt/rGO composites as a novel co-reaction accelerator. Among them, Pt nanoparticles were used to improve the electrical conductivity of CeO2, and the use of rGO as a substrate allows for a more uniform dispersion of CeO2 to increase the catalytic surface area, which effectively improves the performance of the co-reaction accelerator and thus increasing the ECL intensity of the PTCA/S2O82- system. Under the optimal conditions, the designed ECL immunosensor showed satisfactory results in the determination of CA15-3 with a linear range of 12.00 mU mL-1 - 120.00 U mL-1 and a low detection limit of 1.348 mU mL-1. Importantly, the resulting biosensor has good stability, high sensitivity and reliable reproducibility, suggesting its potential application in clinical research.

Microwave plasma torch mass spectrometry for the direct detection of copper and molybdenum ions in aqueous liquids.

Microwave plasma torch (MPT) is a simple and low power-consumption ambient ion source. And the MPT Mass spectra of many metal elements usually exhibit some novel features different from their inductively coupled plasma (ICP) mass spectra, which may be helpful for metal element analysis. Here, we presented the results about the MPT mass spectra of copper and molybdenum elements by a linear ion trap mass spectrometer (LTQ). The generated copper or molybdenum contained ions in plasma were characterized further in collision-induced dissociated (CID) experiments. These researches built a novel, direct and sensitive method for the direct analysis of trace levels of copper and molybdenum in aqueous liquids. Quantitative results showed that the limit of detection (LOD) by using MS(2) procedure was estimated to be 0.265 µg/l (ppb) for copper and 0.497 µg/l for molybdenum. The linear dynamics ranges cover at least 2 orders of magnitude and the analysis of a single aqueous sample can be completed in 5-6 min with a reasonable semi-quantitative sense. Two practical aqueous samples, milk and urine, were also analyzed qualitatively with reasonable recovery rates and RSD. These experimental data demonstrated that the MPT MS is able to turn into a promising and hopeful tool in field analysis of copper and molybdenum ions in water and some aqueous media, and can be applied in many fields, such as environmental controlling, hydrogeology, and water quality inspection. Moreover, MPT MS could also be used as the supplement of ICP-MS for the rapid and in-situ analysis of metal ions. Copyright © 2016 John Wiley & Sons, Ltd.