Glyphosate detection and quantification is still a challenge. After an extensive review of the literature, we observed that Fourier transform infrared spectroscopy (FTIR) had practically not yet been used for detection or quantification. The interaction between zinc oxide (ZnO), silver oxide (Ag₂O), and Ag-doped ZnO nanocrystals (NCs), as well as that between nanocomposite (Ag-doped ZnO/AgO) and glyphosate was analyzed with FTIR to determine whether nanomaterials could be used as signal enhancers for glyphosates. The results were further supported with the use of atomic force microscopy (AFM) imaging. The glyphosate commercial solutions were intensified 10,000 times when incorporated the ZnO NCs. However, strong chemical interactions between Ag and glyphosate may suppress signaling, making FTIR identification difficult. In short, we have shown for the first time that ZnO NCs are exciting tools with the potential to be used as signal amplifiers of glyphosate, the use of which may be explored in terms of the detection of other molecules based on nanocrystal affinity.

Aiming to investigate the graphene usage in optical fiber surface plasmon resonance sensor probes, a theoretical analysis of sensitivity, reflectance, normalized transmitted power, full width at half maximum, and figure of merit (FOM) as a function of the sensing region length for different configurations has been developed. Here, some noble metals, such as gold (Au), silver (Ag), and copper (Cu) have been used as part of the sensing region. Considering aqueous solutions as analytes, the deposition of graphene layers over the metallic layer has improved the performance of the sensor probes. Three graphene-optimized probes have been proposed, one for each metal. When considering water as the surrounding medium, the configuration Cu-graphene-coated probe is the most sensitive, with a sensitivity of 6241 nm/RIU, representing more than two times the sensitivity for a Cu-based probe. On the other hand, the Ag-graphene-coated probe presents the maximum FOM of 75.523 RIU ^-1 . The deposition of graphene layers over the Au-coated probes causes an increase in the sensitivity from 2581 nm/RIU to 4201 nm/RIU.

The sensing properties of thin copper (Cu) films near the surface plasmon resonance (SPR), were re-evaluated for the metal-air and metal-water interfaces and compared with gold (Au) films. For this, we used three different SPR sensing designs, i.e., a prism-based set-up, an optical fiber-based system, and a grating coupler-based solution. Optimum SPR-excitation conditions are restricted to a Cu-metal film thickness of 45±5 nm for the ATR set-up in aqueous solution. The impacts of the surface Cu-oxide layer were discussed and prevented employing an Au ultra-thin protective overlayer. This strategy proved to be efficient for non-reversible binding. Cu-SPR responsivities are higher for the prism-based set-up (quite similar to Au-SPR ones) than the ones for the optical fiber-based system and a grating coupler-based solution. In contrast to thin Au films, bovine serum albumin (BSA) and other proteins do not bind irreversibly onto thin Cu-films. Our findings confirm the suitability of thin copper films for selected SPR sensing applications.

Research focused on improving the sensitivity of SPR analytical technology has led to the investigation of different electric field enhancement elements for incorporation with classic sensor structures. Over the past ten years, considerable attention has been given to ceramic, metal oxide, and 2D materials that not only improve the magnitude of the field but are also used as affinity layers for improved adsorption of molecules. However, focusing on the improvements these materials deliver can lead designers to explore only some of themultiple dependencies associated with sensitivity. When using the angular interrogation mode, the impacts of working with different wavelengths are generally disregarded, as a fixed value of λ=633 nm is commonly adopted. Choosing 633 nm is often justified for achieving near-zero reflectivity and good sensitivity. However, newer SPR designs lack the determination of optimal wavelength-dependent sensitivity points. This article numerically investigates sensitivity as a function of wavelength for SPR sensors. We systematically study the effects of operating outside λ=633 nm and show that the signature produced by bare metal sensors does not always resemble the signatures produced by field-enhanced designs. Examinations are based on Graphene and BaTiO ₃ . Furthermore, we demonstrate how imposing thresholds on optimization targets can be leveraged to sustain high-sensitivity results, and we elaborate on the pertinent tradeoffs. Our approach shows further performance improvements in designs for which highly efficient benchmarks have already been demonstrated.

A bi-directional linear peristaltic pump is presented that avoids use of a rotating step motor and rollers. Fluid displacement, flow and pump function, respectively, are achieved by means of three electro-magnetic actuators. They are electronically controlled and designed to periodically squeeze an elastic tube that contains the liquid. The device reveals a very simple construction, is maintenance free, has very low power consumption, thus accounting for very low manufacture and operation costs. Upon reducing the size of the actuators, it can be easily integrated with micro fluidic arrangements. Flow and pressure pulsation can be reduced by increasing the number of actuators. A finite element-based numerical model has been developed, using the fluid structure interaction (FSI) model. The flow dynamics inside the tube has been treated, using the coupling between the Navier-Stokes and the elastic displacement equations of the elastic tube. The appropriate and optimum timely driving sequence of the actuators, as well as the response characteristics of the physical system, were also numerically evaluated. Experimental results fully agree with the numerical simulation results. The dynamic range of the flow rate was determined as ranging from 7 00μ/min to 79ml/min, while the back pressure varies between 400 mmHg to 14 mmHg.