The peculiarities of absorption spectra formation of the porphine derivatives upon attachment of NO₂ group to the Cm-position of the tetrapyrrolic macrocycle have been studied. Using quantum chemistry methods, the molecular conformation of the substituted porphine molecule was optimized, the energies of molecular orbitals were determined, and electronic absorption spectra were calculated. It was found that the electronic interaction between the macrocycle and the NO₂ group is determined by the orientation of the nitro group relative to the macrocycle mean plane. It has been established that the energy of the LUMO and HOMO–1 orbitals significantly depends on the value of the dihedral angle θ between the macrocycle mean plane and the plane of the nitro group, while the energy of the LUMO+1 and HOMO orbitals varies slightly. As a result, the S0→S₁ and S0→S₂ absorption bands have bathochromic shifts, whose magnitudes are different and depend on the configurational composition of the transitions. The oscillator strength of the S_0→S₁ transition turns out to be greatest in the coplanar conformer, which has minimal configuration interaction, and the oscillator strength of the S₀→S₂ transition increases sharply in the orthogonal conformer, in which the LUMO and LUMO+1 are quasi-degenerate. All spectral characteristics can be presented as functions of the weighted sum of cos²θ and cos²2θ, taking into account the configuration composition of electronic transitions.

   The article provides an overview of techniques for increasing the sensitivity of atomic and molecular spectroscopy in the study of microsamples taken from paintings, which were developed at the Institute of Physics of the National Academy of Sciences of Belarus (more than 200 artworks). The study of only microsample of a paint layer from the painting “The Birth of Venus” using laser induced breakdown spectroscopy, Fourier transform infrared spectroscopy, and Surface enhanced Raman scattering is presented as an example of the multi-analytical approach. The results of the study allow one to conclude that the work was created in the glue tempera technique. The chrome orange, lithopone and iron oxide pigments (like red or yellow ochers, for example) were identified. Therefore, the artwork could be created no earlier than the last quarter of the 19^th century.

   Magnetically induced (MI) transitions of 85Rb atoms, D2 lines 5S1/2–5P3/2, Fg=3→Fe=1 with circular polarization σ, the intensities of which are zero in a zero magnetic field, have been studied experimentally and theoretically, but in magnetic fields at 0.5–1 kG, the intensities of the transitions noted above increase significantly. To implement the process of electromagnetic-induced transparency (EIT) in a strong magnetic field of ~1 kG MI, the Fg=3→Fe=1 transition was used for the first time at the probe radiation frequency, the frequency of the coupling radiation is resonant with the Fg=2→Fе=1 transition. The generated EIT resonance is located on the low-frequency wing of the spectrum. It is shown that EIT resonance is formed only when the probe and coupling radiations have the same circular polarization σ. This is true for all cases when MI transitions Fе – Fg = ΔF = –2 are used.

   It has been shown using the chemiluminescence technique that in the case of TiO₂:MoO₃ composites, contrastingly to TiO₂ photocatalysts, the process of superoxide photogeneration appears to be completely suppressed, whereas the photoelectron trapping in the MoO₃ phase accompanied with the production of Mo(V) reduced states facilitates long-term generation of hydrogen peroxide that plays a role of biocide agent. It has been also shown that the TiO₂:MoO₃ accumulating photocatalysts are fully reversible and the cycle of photocharging followed by peroxide generation can be repeated many times.

   The processes of formation and dispersion of monoclinic and hexagonal molybdenum trioxide phases during the course of thermoinduced polycondensation of molybdic acid in aqueous medium at 100 °C were investigated with the use of dynamic light scattering technique. It has been shown that programmed changing of the concentration of the reaction medium makes it possible to exert an effective control over the nucleation and particle growing in the solution and permits one to obtain perfect prismatic crystallites of metastable hexagonal molybdenum trioxide with the medium size from 200–500 nm to 10 μm.

   Optically detectable magnetic resonance spectra were measured for NV-centers’ ensembles in CVD-diamonds with different ¹³C content. The obtained spectra are described using a model based on the spin Hamiltonian. Using the constructed model and experimental data, the magnitude of the magnetic field applied to the sample was estimated.

   By the method of high-frequency repetitively pulsed f ~ 10–13 kHz laser radiation with a wavelength λ = 1.064 μm and a power density q = 57 MW/cm² on La_0.13Bi_0.87Fe_O3 target at a pressure in the vacuum chamber p = 4.6 Pa nanostructured thin films on a silicon substrate have been obtained. The morphology of thin La_0.13Bi_0.87FeO₃ films was studied using atomic force microscopy. Transmission spectra of La0.13Bi0.87FeO3 films were obtained in the visible, near and mid-IR regions. The electrophysical characteristics of La_0.13Bi_0.87FeO₃/Si structures were analyzed.

   A novel technique was developed for fabrication of bilayer sandwich-type structures based on monolayers of laterally oriented silver nanoplates electrostatically deposited onto thin polymer films. We demonstrate a linear dependence of surface-enhanced Raman scattering (SERS) signal of 4-mercaptobenzoic acid ligand layer on surface concentration of deposited silver nanoplates in monolayer. We show the twofold enhancement of surface-enhanced Raman scattering signal of analyte, which is placed in the gaps between silver nanoplates monolayers in bilayer sandwich structures, comparing to the signal from a single silver nanoplates monolayer, with identical surface concentration of analyte molecules.

   We have functionalized the surface of hydroxyapatite (HA) particles with silver nanoparticles by reducing silver nitrate in the presence of glucose or hydrazine hydrochloride. Two types of (HA)Ag nanocomposite presumably possessing the excess of negative and positive charge (HA)Ag-I and (HA)Ag-II, respectively, were obtained. Plasmonic coatings of (HA)Ag-I and (HA)Ag-II nanoparticles were formed on the surface of glass substrates using the droplet deposition method, and their structural and spectral properties were studied. A comparative study of the intensity of surface-enhanced Raman scattering (SERS) spectra of cationic and anionic porphyrins CuTMpyP4 and CuTPPS4, as well as rhodamine 6G, adsorbed on the surface of both types of nanocomposites was carried out. It has been established that plasmonic structures (HA)Ag-I provide the greatest enhancement of the SERS signal for the cationic porphyrin CuTMpyP4, while for the anionic porphyrin CuTPPS4 adsorbed on films of the (HA)Ag-II composite, a high spectral intensity is observed, which is almost forty times of magnitude higher than in the case of (HA)Ag-I. For Rh6G molecules with charge +1, the efficiency of SERS signal amplification by (HA)Ag-II nanostructures is several times higher than by plasmonic films of (HA)Ag-I. Thus, the results of the work demonstrated the possibility by changing the synthesis conditions to obtain SERS-active substrates with a high efficiency of SERS enhancement for both anionic and cationic analyte molecules.

   The effect of modification of the surface of polystyrene plates for immunoassay with silver nanoparticles and polyelectrolytes on the fluorescent signal of adsorbed antibodies with fluorescent labels IgG-FITC, IgG-AF488 and IgG-AF647 was studied. The resulting solid phase is characterized by an increased sorption capacity by 30–50 % compared to high-binding polystyrene (Greiner, Austria) and the ability to enhance the fluorescent signal of labels due to the plasmonic effect, which together ensures an increase in fluorescence intensity by 3–15 times, depending on the type of the plate surface, the nature of the polyelectrolyte, the optical and physicochemical properties of the labeled antibodies.

   The electronic structure of cylindrical conjugated macromolecules of boron and nitrogen atoms modeling short open nanotubes of zigzag (n,0) and armchair (n,n) types is calculated by using the density functional theory with B3LYP hybrid functional in the 6-31G basis set. Their stability as a function of diameter and length is studied. It is shown that a constant electric field applied along the tubes leads to a “compression” of the energy gap in the electron energy spectrum of the nanotubes to ≈ 0.2 eV. In the framework of the emission molecular orbitals theory, the threshold of field electron emission from boron-nitride nanotubes is calculated. It is shown that, despite the isoelectronicity of conjugated systems of boron-nitride and carbon nanotubes, the substitution of carbon atoms in the nanotube framework for nitrogen and boron atoms leads to a decrease in the threshold field strength of the field emission. It is revealed that the diameter of boron-nitride nanotubes has virtually no effect on the emission molecular orbital.

   Poly(vinyl alcohol) (PVA)–phosphotungstic acid (PTA) nanocomposite films were produced from aqueous solutions with the addition of ethylene glycol (EG), which is a plasticizer for PVA and contains OH groups capable of being electron donors during the photoreduction of PTA. Spectroscopic studies have shown that the addition of EG significantly enhances the photochromic properties of nanocomposites caused by photoinduced electron transfer from the organic matrix of nanocomposite to PTA molecules.

   5 types of plastics were classified based on NIR spectra of optical density using multivariate cluster analysis in principal component space. Accuracy above 0.96 is obtained by ranking spectral variables by decreasing variance of measured optical density. Changes in polycarbonate VIS-NIR spectra during thermal degradation were modeled using partial least squares method with searching combination moving windows of optimal width. A quantitative calibration of the aging term up to 11.5 years was obtained with a root mean square error of the estimate around 19 days and a residual predictive deviation of more than 45.

   The photophysical properties of these two carboxyfluorescein bifluorophores were investigated in more depth, including the effects of pH and different solution media on the photophysical properties, as well as comparing the fluorescence effect of bifluorophores with monomers carboxyfluoresceins (5-FAM and 6-FAM) in conjugates with protein molecules. The results showed that both bifluorophores fluoresced perfectly in alkaline medium, but the fluorescence intensity decreased at pH values of 6–7, and almost disappeared in acidic medium. The fluorescence of (6-FAM)₂ is very sensitive to the solution composition, while (5-FAM)₂ is more stable and almost independent of the solution medium. When bifluorophore-protein conjugate is formed, the quantum yield of bifluorophore fluorescence decreases more strongly compared to monomers carboxyfluoresceins, but the overall fluorescence intensity of the bifluorophore was not inferior to that of the two carboxyfluorescein monomer-protein conjugates due to the high extinction coefficient of the bifluorophore (~140,000 M^–1 . cm^–1).

   Parallel factor analysis PARAFAC is widely used in relation to fluorescence excitation/emission spectra to track the movement of water masses, as well as to study seasonal changes in the composition and content of dissolved organic matter. The stage of selecting the number of components is one of the most difficult when using factor analysis. The widely used method of analyzing loads when splitting the original set into halves in many cases does not allow determining the best model due to the closeness of their statistical estimates. Since the use of regularization with a penalty for the sum of parameter modules tends to lead to sparse solutions in which some of the coefficients are equal to zero, the use of this approach allows one to select those variables that carry useful information. A procedure is proposed for selecting the number of components when performing parallel factor analysis of fluorescence spectra using a penalty for the 1- and 2-norms of the solution.

   Based on the method of photo-orientation of azo dye AtA-2, an electrically controllable Fresnel lens has been developed, representing a microstructured liquid crystal element with alternating rings with twist- and planar orientations of the liquid crystal director. It is shown that the use of the control voltage allows one to control the efficiency of laser radiation focusing, as well as to turn off the lens. The optimum value of the control voltage (~3 V) is determined, at which the maximum focusing efficiency and satisfactory quality of imaging in a wide spectral range from 530 nm to 1.1 μm are achieved.

   The patterns of formation of the spatial-energy profile (SEP) of the visibility zone (VZ) of active-pulse vision systems (APVS) have been numerically studied, taking into account the ratio of the cross sections of the observation object A_ob and the laser illumination beam Alas in the plane of the object location. For this purpose, the concepts of the boundary distance S_bd (at which A_ob = A_las) and the multiplier w = A_ob/A_las, which is added to the well-known equation for the recorded APVS signal, are introduced. Taking into account the finite length of the VZ, the following cases can be distinguished. If S_bd ≥ S_end (end point of the VZ) within zone w =1. Previously known studies were performed for this case. When Sstart (starting point of the VZ) ≤ S_bd < Send within the VZ there may first be a range of distances with a maximum value w₁ = 1, after which there is a range with a decreasing factor to a certain minimum value w₂ < 1. And finally, when S_bd < S_start within the limits of the VZ w₁(S_del1) < 1 and w2(S_del2) < 1 (in this case, w₂ is always less than w₁, and the delay distance S_del1 < S_del2). Taking into account the multiplier w < 1 leads, in the corresponding range, to a change in the shape of the VZ, maximum signal values and other characteristics implemented within the visibility zone. A generalizing parameter, that in practice characterizes the influence of the range of distances, where w < 1, is the maximum operating range (MOR) of the system. For the parameters used in the calculations, taking into account the indicated influence led to a decrease in MOR by 2.9—5.0 times. The main mechanisms of influence of the relative position of S_bd and the VZ on the characteristics of the probe are given. The main results of numerical modeling are confirmed experimentally.

   A study of the solvent effect was used to describe the pronounced change in position of the UV-Visible absorption band associated with changing the polarity of the medium. Murexide compound which has different position of UV-Visible absorption band in the protic and non-protic solvents. Various solvent parameters, such as dielectric constant, refractive index, Kamlet-Taft and Catalan parameters were used for the evaluation of the solute-solvent interactions and the solvatochromic shifts of the UV-Vis absorption maximum of the investigated indicator. The phenomenon of tautomerism is explained. The Kamlet-Taft solvent scale was found to be the most appropriate to describe the solvatochromic behavior of the murexide. The dissociation constant pKa and the isosbestic point of the investigated compound showed the presence of the individual predominate ionic species in different pH ranges.

   STACK Family borates are promising compounds for optical applications. Synthesis and luminescence of Sr₃Y(BO₃)₃ borate belonging to the STACK family is described. Trivalent activators Tb³⁺ and Gd³⁺ occupy Yttrium sites. Owing to fixed, well-separated positions (Y-Y distance 7.396 Å), a large concentration of Gd³⁺, as much as 50 % relative to Y, could be accommodated without causing concentration quenching. In the case of Gd³⁺, both excitation and emission lines arise in f–f transitions. Photoluminescence emission is obtained in UV regions. In the case of Tb³⁺, concentration quenching was observed above 2 %. Prominent excitation of Tb³⁺ is in the form of a band arising in f–d type transition, while emission comes from f–f transitions. Emission lifetimes are of the order of milliseconds, typically forbidden f–f transitions.

   Dy³⁺ and Sm³⁺-doped Na₂Al₂B₂O₇ phosphors were synthesized at 850 ºC for 6 h in air. The phase analyses of all prepared borates were carried out using powder X-ray diffraction (XRD). A spectrofluorometer was used to examine the photoluminescence (PL) characteristics of the prepared phosphors at room temperature. When excited at 350 nm, Na₂Al₂B₂O₇:Dy³⁺ radiates at 481–491, 575–583, and 673 nm. After being excited at 402 nm, Na₂Al₂B₂O₇:Sm³⁺ radiates at 561, 603, 650, and 709 nm. As a result of this study, two new optical materials that emit light in the visible region were prepared.

   An innovative, meticulously crafted, targeted, expeditious, precise, and cost-effective methodology was pioneered utilizing UV-Vis Spectrophotometry for the quantitative determination of Mirabegron in both its pristine state and pharmaceutical tablet formulation. Following thorough deliberation on factors such as solubility, stability, toxicity, and carcinogenicity, petroleum ether emerged as the solvent of choice, aligning with the principles of environmentally conscious methodology. The absorption maxima were unequivocally detected at a wavelength of 250 nm, making petroleum ether the solvent of choice. The method adheres faith-fully to Beer’s law within a concentration range spanning from 0.004 to 0.016 mg/mL, boasting a remarkable correlation coefficient of 0.9945. LOD and LOQ were meticulously computed from the dataset, yielding values of 0.0001663 and 0.0005039, respectively. The relative standard deviation, meticulously derived from the dataset, stands at less than 2 %. Moreover, in the rigorous accuracy assessment, Mirabegron's recovery percentage fell impressively within the narrow band of 98.62 to 101.46 %. During both the Intraday and Interday precision evaluations, the % Assay remained consistently within the stringent range of 99.63 to 101.12 %, affirming the method’s precision. Furthermore, adherence to the rigorous guidelines outlined in ICH Q2 (R1) was ensured throughout the comprehensive validation process, consolidating the method’s credibility and suitability for analytical applications.

   Ivacaftor is a selective small molecule potentiator Transmembrane Conductance Regulator protein used for the treatment of cystic fibrosis. This report describes the validation of simple, rapid, sensitive and cost-effective zero-order and first-order derivative spectrophotometric methods for the estimation of ivacaftor in bulk and in its marketed formulation. Preliminary spectrophotometric analysis of the drug was carried out in methanol and a total of 21 parametric variations were considered. Three selected method variants employing absorbance (zero-order), peak-peak (first order) and peak-zero (second order) techniques were assessed for their stability indicating potential in stress degraded solutions of the drug. The developed method was validated with respect to parameters including linearity, accuracy, precision, robustness and solution stability. Excellent linearity was observed in the concentration range of 5.0–30.0 μg/mL with a correlation coefficient of 0.99 and above for the selected method variants. The limits of assay detection values ranged from 0.90–1.06 μg/mL, and quantitation limits ranged from 2.72–3.22 μg/mL for the proposed method variants. The proposed methods were used to quantify the drug in its marketed tablet formulation, and good recoveries ranging from 95.98 to 98.81 % were obtained.

   The widespread use of pesticides poses many potential risks to food safety and human health. Thus, rapid and accurate detection methods for pesticide residues need to be established. In this study, ultraviolet (UV) spectroscopy coupled with support vector regression and variable selection methods was used to quantitatively detect the content of imidacloprid in apple juice. First, the UV spectra of different imidacloprid concentrations in apple juice were collected, and the acquired spectra were preprocessed by Savitzky-Golay smoothing. Then, the feature variables were selected by the variable iterative space shrinkage approach (VISSA), iteratively retains informative variables (IRIV), and random frog (RF) algorithms. Finally, particle swarm optimization support vector regression (PSO-SVR) prediction models based on the feature variables and the full-spectrum variables were established to detect imidacloprid in apple juice. The results showed that the VISSA-PSO-SVR model had the optimal predictive performance, the determination coefficient of the prediction set (Rp²) was 0.99933, and the root mean square error of the prediction set (RMSEP) was 0.0894 mg/L. The results from this study indicated that the combination of UV spectroscopy and the VISSA-PSO-SVR model could be used for the quantitative detection of imidacloprid in apple juice.

   The present work describes the development and validation of zero-order derivative and first-order derivative UV-Vis spectrophotometric methods for the quantitative determination of viloxazine hydrochloride. The spectrophotometric determination was performed between 200–400 nm and the first-order derivative spectrum was obtained by comparing absorbance to wavelength. The developed method was validated under ICH guidelines for linearity, precision, accuracy, limit of detection and quantification, and robustness. The correlation coefficient value of the methods was 0.9989 (method A) and 0.9979 (method B) with a limit of detection of 3 µg/mL and a limit of quantification of 9 µg/mL. The precision of the methods was confirmed by calculating the % relative standard deviation, which is acceptable as per guidelines. The accuracy of the methods was calculated and represented in terms of % mean recovery. Moreover, the Greenness profiles of the developed UV method were assessed using the Green Analytical Procedure Index (GAPI) and the AGREE evaluation method. The results revealed adherence of the described method to the green analytical chemistry principles. We successfully developed and validated the UV method according to ICH guidelines. The method was proved for the analysis of marketed formulations.

   Folic acid (FA) is an important nutrient for several physiological functions, including DNA synthesis, amino acid homeostasis, and normal blood production. With the increased circulation of counterfeit and substandard drugs worldwide, it is vital to ensure the quality of the FA tablets using a simple and validated analytical method that can be applied for routine QC of FA tablets in developing countries or worldwide. We developed two validated spectrophotometric methods for the quantitation of FA in tablet dosage forms. The developed methods were applied to bulk and FA powdered tablets dissolved in alkaline media using a 0.1 N NaHCO₃ solution (method 1) and a 0.1 N NaHCO3/0.1N HCl solution (method 2). The established wave lengths λ_max were found to be at 256, 283, and 366 nm (method 1) and at 295 nm (method 2). Method validation parameters included linearity, accuracy, precision, LOD, and LOQ. The accuracy and precision (RSD %) of the methods were tested by direct sample/standard comparison (n = 5) and found to be simple, selective, and robust. Good linearity was achieved, with correlation coefficients ≥ 0.9923 and limits of detection and quantification ranging from 1.46 to 2.44 ug/mL and from 4.45 to 7.38 ug/mL at 256, 283, and 366 nm (method 1). Likewise, the LOD and LOQ values of method 2 were 1.53 and 4.66 µg/mL, respectively. The assay results for FA tablets were 102–107% for method 1, with RSD% between 3.73 and 7.75 %. For method 2, the assay results for FA tablets were 106.54 ± 2.34 % with a linearity of 0.9998. These developed methods provide a simple alternative to the important published methods for assaying of FA in tablet formulations.

   The carbon levels in low-alloy steel samples were measured using laser-induced breakdown spectroscopy (LIBS) and a random forest (RF) method. When employing the RF method, the root-mean-square error of cross-validation (RMSECV) criterion was first used to select the spectral range of the spectral variables for RF model input, to prevent over-fitting of the RF model when only a few relevant variables are accompanied by many other variables. Second, the out-of-bag (OOB) error criterion was used to optimize the numbers of decision trees (ntree) and characteristic variables (mtry) in the RF model, which optimizes the RF structure. The availability of a large amount of relevant spectral information, coupled with the remarkable regression capacity of RF, greatly improved the carbon analytical accuracy. The results showed that the root-mean-square error of prediction (RMSEP) was 0.034 wt. % for the calibration curve method and 0.023 wt. % for the RF method; the reduction afforded by the latter method was 32.4 %. Thus, the RF method improved the carbon analytical accuracy for low-alloy steels.

   Laser-induced breakdown spectroscopy (LIBS) technology faces the challenge of redundant or irrelevant features when dealing with high-dimensional data of steel. To enhance the accuracy and interpretability of multivariate classification, this study introduces an innovative hybrid feature selection (FS) method that skillfully combines the filtering characteristics of the select percentile (SP) algorithm with the embedded advantages of the elastic net (EN) algorithm. Under this framework, the support vector machine (SVM) algorithm was applied for classification, demonstrating outstanding performance with an accuracy, precision, and F1 score of 0.9888, 0.9895, and 0.9889 on the test set, respectively. To address the ‘black box’ nature of the SVM algorithm, this paper further introduces the local interpretable model-agnostic explanations (LIME) method. LIME allows for the visualization of the importance of each variable, thereby enhancing the interpretability and credibility of the model. Overall, the model and methods proposed in this study show significant effectiveness in eliminating redundant or irrelevant features and in precise classification, effectively solving most of the challenges faced by LIBS in steel classification issues.

   The atmospheric wind field in the troposphere and stratosphere notably impacts human production and life. The lidar is one of the most effective means of detecting the atmosphere in this region due to its high resolution and sensitivity. To meet this need, aerosol and molecular backscattering signals of different wave-lengths were analyzed via lidar technology. The results showed that the 355 nm laser provides an advantage in detecting the atmosphere under clear weather conditions, and the 1064 nm laser achieves superior detection performance under severe haze weather conditions, while the detection performance of the 532 nm laser varies between those of the other lasers. The detection performance of the system was simulated using a 532 nm laser, and the maximum detection height reached 43 km under clear weather conditions and 28 km under polluted weather conditions. This analysis provides support for obtaining atmospheric wind fields in the troposphere and stratosphere under all weather conditions in the future.

   Terahertz (THz) single-pixel imaging has received major research attention because of the lack of a suitable high-resolution array detector for THz imaging applications. Improving both imaging speed and quality has become a research hotspot for this field in recent years. In this study, a terahertz single-pixel imaging system with Hadamard spatial encoding was constructed by using optically induced semiconductor materials to perform THz wave modulation. Sparse coding was added to the system’s reconstruction algorithm to enhance imaging quality. Numerous image patches were then collected from a natural image set to train an overcomplete dictionary and each patch in the measured image was reconstructed through sparse representation. To validate the effectiveness of the proposed algorithm, the reconstruction performances of different algorithms were compared under various conditions (i.e., with sampling rates varying from 5 to 100 % and with noise levels within a signal-to-noise ratio range of 10–50 dB). The proposed algorithm, in combination with sparse representation of an overcomplete dictionary, showed a higher peak signal-to-noise ratio and a lower mean square error than both the inverse Hadamard transform (IHT) and TVAL3 algorithms. Finally, THz imaging experiments were performed to validate the algorithm’s reconstruction performance at sub-Nyquist sampling rates. The experimental and simulation results coincided closely, thus indicating that the use of the proposed algorithm enhances the signal-to-noise ratio of the reconstructed image, reduces its mean square error, and retains greater image detail. The proposed algorithm was demonstrated to be the preferred choice for THz single-pixel imaging applications.

   A procedure based on dispersive liquid-liquid microextraction (DLLME) for cadmium (Cd) quantification in an Iraqi environmental matrix by flame atomic absorption spectroscopy (FAAS) was applied in this work. A case study approach was chosen to obtain further in-depth information on the Cd levels and to evaluate the effectiveness of N-salicylideneaniline (SAN) as a complexing agent for preconcentration and extraction of Cd. Univariate strategy was utilized for achieving the optimum extraction conditions: 75.0 µL of carbon tetrachloride as the extraction solvent, 10 mL of a sample solution adjusted the pH at 8.50 containing 0.8% (w/v) SAN, and 1400 µL of methanol as the dispersive solvent, within 30 s complexation time. The estimated limits of detection (LOD) and quantification (LOQ) under optimum conditions were 0.26 and 0.87 µg/L, respectively. Enrichment factors were obtained in two manners, found to be 24.4 and 44.3. To evaluate the accuracy of the method, known amounts of analytes were spiked and compared with the results achieved using microwave digestion/graphite furnace atomic absorption spectrometer (MWD/GF-AAS) for solid samples, and direct graphite furnace atomic absorption spectrometer (GF-AAS) for water samples. Procedure was applied for analyzing eight environmental samples, the Cd levels for water samples ranged from 3.01 to 7.33 µg/L with a relative standard deviation (4.1–10.4 RSD %), while the concentration for the solid sample (Mentha piperita) was 2.71 µg/g (RSD % = 7.4). DLLME/FAAS proposed procedure is effective, simple, and has the benefit of minimizing the organic solvent consumption, by a few microliters, which results in little waste.