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Optical diagnostics methods are significantly appealing in biological applications since they are non-destructive, safe, and minimally invasive. Laser-induced fluorescence is a promising optical spectrochemical analytical technique widely employed for tissue classification through molecular analysis of the studied samples after excitation with appropriate short-wavelength laser light. On the other hand, diffuse optics techniques are used for tissue monitoring and differentiation based on their absorption and scattering characteristics in the red to the near-infrared spectra. Therefore, it is strongly foreseen to obtain promising results by combining these techniques. In the present work, tissues under different conditions (hydrated/dry skin and native/boiled adipose fat) were distinguished according to their fluorescence emission, absorption, and scattering properties. The selected tissues’ optical absorption and scattering parameters were determined via Kubelka–Munk mathematical model according to the experimental tissue reflectance and transmittance measurements. Such measurements were obtained using an optical configuration of integrating sphere and spectrometer at different laser wavelengths (808, 830, and 980 nm). Moreover, the diffusion equation was solved for the fluence rate at the sample surface using the finite element method. Furthermore, the accuracy of the obtained spectroscopic measurements was evaluated using partial least squares regression statistical analysis with 0.87 and 0.89 R-squared values for skin and adipose fat, respectively.

In the present work, nanoparticles-enhanced laser-induced breakdown spectroscopy (N.E.L.I.B.S.) has been used to analyze aluminum alloy. Though LIBS has numerous advantages, it suffers from low sensitivity and low detection limits compared to other spectrochemical analytical methods. However, using gold nanoparticles helps to overcome such drawbacks and enhances the LIBS sensitivity in analyzing aluminum alloy in the current work. Aluminum is the major element in the analyzed samples (99.9%), while Magnesium (Mg) is the minor element (0.1%). Spread of gold nanoparticles onto the Al alloy and using a laser with different pulse energies have been exploited to enhance the Al alloy spectral lines. The results showed that Au NPs had successfully improved the alloy spectral lines intensity by eight times, which could be useful for detecting many trace elements in higher matrix alloys. Under the assumption of local thermodynamic equilibrium (LTE), the Boltzmann plot has been used to calculate the plasma temperature. . Besides, the electron density was calculated using Mg and H lines at Mg (I) at 285.2 nm and Hα (I) at 656.2 nm, respectively. 3D contour mapping and color fill images contributed to understanding the behavior of the involving effects.

In this work, laser-induced breakdown spectroscopy (LIBS) was applied to qualitatively evaluate lead adsorbed from industrial wastewater by nano-CaCO3. Eggshell as a natural source of CaCO3 has been used as a sorbent owing to its low cost and unrivalled adsorption capacity to remove Pb from contaminated water. The structure and morphology of CaCO3 nano-powders were investigated using scanning electron microscopy (SEM), transmission electron microscope (TEM) and Fourier transforms infrared (FTIR). LIBS results were experimentally validated by the results obtained using portable X-ray fluorescence spectroscopy (pXRF) and energy dispersive X-ray (EDS), which confirmed the feasibility of using LIBS to detect traces of Pb ions, while the adsorption process is applied under governing parameters. Langmuir and Freundlich isotherm models were used to model the experimental data. The kinetics of adsorption mechanisms were studied using Lagergren's pseudo-first-order and McKay and Ho's pseudo-second-order. The obtained results demonstrated that bio-CaCO3 nanoparticles could be used as an effective lead-sorbent from wastewater. Accordingly, it is possible to utilize this adsorption technique as a promising practical approach for the treatment of lead-contaminated industrial wastewater and its recirculation. Graphical abstract Highlights Natural nano CaCO3 from eggshell was prepared mechanically as a low-cost adsorbent and characterized by SEM, TEM, and FTIR. The capacity of removing Pb (II) by nano-CaCO3 was dependent on pH, metal concentration and contact time . LIBS was used for qualitative analysis of adsorbed Pb (II) and the results were validated with those obtained by EDX and pXRF spectrometry; in addition, isotherm models and kinetics of adsorption mechanisms were investigated.