Reinvestigation on High-Valent Cobalt for the Degradation of Micropollutants in the Co(II)/Peroxymonosulfate System: Roles of Co(III).

Recently, reactive cobalt (Co) species, including Co(IV)-oxo and Co(II)-OOSO3- complexes, were proposed to be the primary intermediates formed during the process of activating peroxymonosulfate (PMS) by Co(II), mainly based on the observation that the methyl phenyl sulfoxide (MPSO) probe was transformed to methyl phenyl sulfone (MPSO2) in this process. However, in this work, we rationalized the results of the MPSO probe assay based on the chemistry of aqueous Co(III), an alternative reactive Co species. Moreover, 18O-labeled water experiments and Raman spectroscopy analysis clearly proved the Co(III) formation in the Co(II)/PMS system. In parallel, sulfate radicals (SO4•-) and hydroxyl radicals (HO•) were also involved in this system. Further, the relative contribution of Co(III) to the abatement of carbamazepine (CBZ), a representative micropollutant, in the Co(II)/PMS system was significantly increased by increasing the Co(II) dosage but was dramatically decreased by improving the PMS dosage and increasing the pH from 3 to 7. Additionally, the degradation pathway of CBZ by Co(III) and the Co(II)/PMS system was comparatively explored, confirming that Co(III) participated in the hydroxylation, carbonylation, deacetylation, and ring reduction of CBZ by the Co(II)/PMS system. Our work addresses the controversy regarding the reactive Co species involved in the Co(II)/PMS system with evidence of Co(III) as the chief one, which highlights the significance of re-evaluating the relative contribution of Co(III) in relevant environmental decontamination processes.

Imaging Sensor for the Detection of the Flow Battery Via Weak Value Amplification.

Flow battery electrodes are vital for performing redox reactions, and an in-depth understanding of reaction kinetics and spatial distribution differences in electrodes is very important for improving the efficiency of electrochemical reactions. In this study, a reflection-type phase-sensitive weak measurement imaging system was developed for the detection of flow batteries. The phase difference between two polarization components in total internal reflection caused by electrode redox processes was measured by weak value amplification. The resulting refractive index resolution of the imaging system was estimated to be 2.8-4.2 × 10-6 RIU. The real-time monitoring ability of the system was demonstrated by linear sweep voltammetry tests of vanadium redox batteries. Compared to traditional optical methods, the proposed weak measurement imaging sensor did not require coating, as it can be used in acid electrolytes of vanadium flow batteries. Meanwhile, the weak value amplification effect led to a higher resolution than the total internal reflection system shown in our previous work, thereby resulting in more accurate detection of electrochemical reactions. In sum, the proposed sensor looks very promising for the detection of electrochemical reactions in flow batteries, water splitting, electrochemical corrosion, and electrocatalysis.

Detection of Macromolecular Content in a Mixed Solution of Protein Macromolecules and Small Molecules Using a Weak Measurement Linear Differential System.

In this paper, we propose a linear differential detection system based on a frequency domain weak measurement. The system can be used for detecting optical substances. Moreover, we completed an experiment to detect himan serum albumin (HSA) content in a mixture of human serum albumin and l-proline via dialysis. This work also proves the differential function of the system. This experiment can be further extended to detecting protein content in a mixed solution that contains protein macromolecules and various small molecules. It is very important for detecting molecules without photomarking in solutions of complex biological samples. In this paper, the system has an optical resolution of 1.39 × 10-5, and resolution of 4.06 × 10-8 mol/L for himan serum protein solution.

Weak measurement-based sensor for the rapid identification of L(+)-ascorbic acid and D(-)-isoascorbic acid.

The ability to identify L(+)-ascorbic acid from D(-)-isoascorbic acid in medicinal products is of practical interest. Based on the method of frequency domain weak measurement, a set of common optical path sensors for identification of L(+)-ascorbic acid and D(-)-isoascorbic acid is established. By quantificationally analyzing the magnitude and offset direction of the spectral central wavelength, a good identification of the concentration and the optically active forms of ascorbic acid has been achieved. The sensitivity and resolution of the sensor for optical rotation can reach 34.35 nm/° and ${5.53} \times {{10}^{ - 5}}^\circ $5.53×10-5 ∘, respectively. The detection resolution for L(+)-ascorbic acid is ${2.00} \times {{10}^{ - 4}}\;{\rm mol}/{\rm mL}$2.00×10-4mol/mL, and that for D(-)-isoascorbic acid is ${2.73} \times {{10}^{ - 4}}\;{\rm mol}/{\rm mL}$2.73×10-4mol/mL. The potential of the sensor in the detection of transparent but optically inactive impurities has been verified by comparative experiments of sodium chloride solution. The sensor also has been applied to identify medicinal vitamin C tablets, which verified the feasibility of the method in optically active pharmaceutical solutions with water-insoluble, optically inactive impurities. Since the sensor has the advantages of high precision, real-time, high robustness, and being non-destructive, it has a great prospect in the field of drug detection containing chiral molecules.

A Differential Detection Method Based on a Linear Weak Measurement System.

Self-reference detection is necessary and important to a biosensor. The linear weak measurement system based on total internal reflection has attracted widespread attention due to its high stability, label-free detection, and easy integration. In this paper, we propose a differential detection method based on the linear total internal reflection weak measurement system. We introduce the half-wave plate (HWP) to convert the H light and the V light to each other, thereby obtaining the difference in phase change of the optical path before and after the HWP. Experiments show that the system can not only achieve differential detection, but also has high stability. The linear differential weak measurement system proposed in this paper not only provides a new differential measurement method for real-time biosensors, but also enriches the types of weak measurement sensors.

Optimization of a quantum weak measurement system with its working areas.

Phase-sensitive weak measurement systems have been receiving an increasing amount of attention. In this paper, we introduce a series of weak measurement working areas. By adjusting the pre-selection and post-selection states and the total phase difference between vertically polarized light and horizontally polarized light, the measurement of the weak value is amplified by several times in one system. Its applicability is verified in a label-free total internal reflection system. The original sensitivity and resolution are improved at different working areas, reaching 1.85 um/refractive index unit (RIU) and 6.808 × 10-7 RIU, respectively.

Optimization of a quantum weak measurement system with digital filtering technology.

In this paper, we propose a post-Gaussian filtering theory for weak measurement in the frequency domain, and propose a highly deformed digital filtering technique that can be used to optimize sensors based on weak-frequency measurement techniques. We completed the experimental verification based on the weak measurement total internal reflection sensor. The experimental results show that digital filtering technology can optimize the system in the working range, sensitivity, and resolution of the frequency domain weak measurement system, so that it can reach 0.210 rad, 3210.9 nm/RIU, and 7.12×10-7 RIU, respectively.

Determination of Tumor Marker Carcinoembryonic Antigen with Biosensor Based on Optical Quantum Weak Measurements.

A phase-sensitive weak measurement biosensor was proposed for the detection of carcinoembryonic antigen (CEA), one common category of tumor markers. The total internal reflection (TIR) at the interface of the prism without precious metal coating was exploited to introduce the phase delay between horizontal and vertical polarizations, which can be determined through the central wavelength shift of output spectra for the sensing of the refractive index of the sample. In the weak measurement analysis, the specific binding reaction of tumor markers with a refractive index change on the surface of the prism can be monitored in real time through the central wavelength shift. With the specific absorption measurement, the feasibility of this weak measurement-based biosensor was experimentally demonstrated. We provide a low cost and convenient approach for tumor marker detection.

Rapid Separation of Enantiomeric Impurities in Chiral Molecules by a Self-Referential Weak Measurement System.

We propose a self-referential fast detection scheme for a frequency domain weak measurement system for the detection of enantiomeric impurities in chiral molecules. In a transmissive weak measurement system, the optical rotation (OR) is used to modify the pre-selected polarization state and the post-selection polarization state. We obtained the sum and difference of the optical rotations produced by the sample and the standard by rotating the quarter wave plate in the system. Then, we estimate the ratio of chiral molecules to enantiomeric impurities using the ratio of the central wavelength shifts caused by the addition and subtraction states described above. In this paper, our system has an optical resolution of 1.88 × 10-5°. At the same time, we completed the detection of the ratio of the two substances in the mixture of L-proline and D-proline in different proportions, which proved that our system can quickly detect the content of enantiomeric impurities in chiral molecules.

Demonstration of a New Characterization Method for Weak Measurement.

In this work, the difference between the weak measurement method and the weak value amplification process and the classical measurement process is thoroughly discussed, and the transition conditions of the weak value enhancement are obtained. A transition mode of the weak measurement and the classical measurement is proposed for the first time, and a better fitting model of the measurement results is found by performing a systematic analysis. On top of that, the importance of the new fitting method for the application of the weak measurement system is verified during the industrial production of organic molecular -nucleic acid, protein, polysaccharide-hydrolysis or synthesis. At the same time, a variety of spectral characterization methods are proposed and the advantages and disadvantages of the different characterization methods are analyzed through carrying out experiments. Consequently, the wide implementation of weak measurement-based detection technology is attained.

Specific detection of glucose by an optical weak measurement sensor.

Diabetes is an important public health problem and finding quick testing methods with high accuracy, reliability, and convenience are important to control the blood glucose of diabetic patients. In this study, a sensor based on a weak measurement scheme was developed for the specific detection of glucose for the first time. The detection of glucose using the proposed method was completed by the high sensitivity and resolution of the weak measurement based on optical rotation detection, as well as the change in the optical rotation before and after the specific oxidation of glucose. The resolution of the as-obtained glucose sensor was around 2.71×10-3 g/L (1.50×10-2 mmol/L), and the detection range was 0-11 g/L (0-61 mmol/L).

Label-free and Non-destruction Determination of Single- and Double-Strand DNA based on Quantum Weak Measurement.

The process of unwinding and renaturation of DNA has been widely used in studies of nucleotide sequence organization. Compared with traditional methods for DNA unwinding and renaturation, the label-free and non-destruction detection technology is significant and desiderated. We realized an optical system based on optical rotation via weak measurement for detection of single- and double-strand state of DNA. The optical rotation, which was induced by the status change of single and double DNA strands, was exploited to modulate the preselected polarization of a weak measurement system. With this modulation, the optical rotation caused by the separation of DNA strands can be determined through the center wavelength shift of the output spectrum. By monitoring the wavelength shift in real time, the separation processes of the DNAs with different base ratio (25% and 70%) and length (4nt and 40nt), and DNAs with three terminally modified cholesterol molecules were experimentally explored in varied pH and temperature conditions. In addition, the detection limit of the DNA concentration was obtained to be 5 × 10-6 mol/L. Our work based on optical rotation detection of single- and double-strand DNA exhibits the unique advantages of real-time monitoring, label-free, non-destruction and simplicity.