Citrus species are well recognized for their wide range of biological activities, including antimicrobial, anticancer, cardiovascular, and renal-protective effects. The objective of this review is to systematically compile and demonstrate the various analytical approaches used to identify and quantify phytochemicals in citrus species. Modern analytical techniques such as thin-layer chromatography (TLC), high-performance liquid chromatography (HPLC, gas chromatography (GC), liquid chromatography–mass spectrometry (LC-MS), and infrared spectroscopy have been explored, alongside classical extraction methods including Soxhlet, maceration, and steam distillation, as well as newer techniques like solvent-free microwave extraction and pressurized liquid extraction. Specific citrus species — Citrus hystrix, Citrus aurantifolia, and Citrus microcarpa and their bioactive constituents are discussed in relation to their pharmacological effects. This review aims to guide future research by providing insights into suitable analytical strategies and highlighting the need for standardization in citrus phytochemical analysis.
Alcohol-based hand sanitizers are essential for hand hygiene and help prevent the spread of infectious diseases. This work focuses on the development and validation of qualitative and quantitative methods for quality control of ethanol-based disinfectants using a low-cost handheld transmission spectrophotometer and chemometrics. Calibration and validation samples, in liquid and gel forms, were prepared with ethanol concentrations ranging from 40 to 90 % v/v. The qualitative method involved constructing a model based on data-driven soft independent modeling of class analogy, enabling the identification of hand sanitizers with an ethanol concentration between 60 and 80% v/v. A sensitivity of 100 % was achieved for both the training and validation sets. The evaluation of the specificity of the constructed model showed satisfactory results when analyzing samples containing ethanol at lower and higher concentrations, as well as samples containing other alcohols. The quantitative method was based on a partial least squares regression model for the determination of ethanol in hand sanitizers. The validation study, conducted using the accuracy profile strategy, showed that the developed method was specific, linear, fair, precise, and accurate over the ethanol concentration range of 40-90 % v/v. The developed and validated methods were successfully used to analyze various commercial ethanol-based disinfectants.
The coordination polymer {[Zn4O(BTB)2]& centerdot;H2O}n (& Ncy;3BTB-1,3,5-tris(4-carboxyphenyl)benzene) was synthesized and tested as a solid-phase extraction sorbent for the determination of highly toxic organic pollutants: polychlorodibenzo-p-dioxins (PCDD), polychlorinated dibenzofurans (PCDF), dioxin-like and non-dioxin-like polychlorinated biphenyls (PCBs) in natural water samples by the method of gas chromatography/high-resolution mass spectrometry (GC-HRMS). The results demonstrated that [Zn4O(BTB)2]n is an effective sorbent for solid-phase extraction of PCDD, PCDF, and PCBs from water samples with a mass fraction of suspended solids less than 1%. The effectiveness of the proposed combination of sample preparation and GC-HRMS analysis was studied for linearity, precision and reproducibility for 7 polychlorinated dibenzo-p-dioxins, 10 polychlorinated dibenzofurans, 12 dioxin-like and 6 non-dioxin-like polychlorinated biphenyls, the content of which is regulated by the European Union Directives. The limits of quantification (LOQ) for dioxins were found to be in the range of 2.5-18.8 pgL-1 and 3.2-14.0 pg L-1 for dioxins and dibenzofurans, respectively. Samples of natural surface waters were analyzed using both the developed SPE method and the liquid-liquid extraction method. All data obtained by the two research methods are in good agreement with each other.
Testosterone (TST), a widely used anabolic steroid, requires sensitive and selective analytical approaches for reliable determination in pharmaceutical formulations and environmental matrices. In this work, its electrochemical properties were examined using cyclic voltammetry under optimized conditions (pH 12.7, 40 degrees C, scan rate 50 mV & centerdot;s-1). TST exhibited an irreversible, diffusion-controlled oxidation process. A linear calibration curve was obtained within the concentration range of 3.47 & times; 10-5 - 3.47 & times; 10-4 M (R2 = 0.999). The method achieved a detection limit (LOD) of 2.08 & times; 10-5 M and a quantification limit (LOQ) of 6.30 & times; 10-5 M. Thermodynamic parameters were calculated as Delta H = 2.59 kJ & centerdot;mol-1, Delta S = 392.22 J & centerdot;K-1 & centerdot;mol-1, and Delta G = -120.22 kJ & centerdot;mol-1, confirming the spontaneity of the redox process. The electrode's electroactive surface area was 0.0054 cm2. High precision was demonstrated, with relative standard deviations of less than 0.5%. The method was successfully applied to the quantification of testosterone in bulk and pharmaceutical formulations, with recoveries consistent with certified values.
Bromine based biocides are widely used in cooling water systems of electric power plants as they are more efficient against biofouling of pipelines than chlorine based ones. Cooling water usually consists of river water spiked with sodium bromide, later certain amount of hypochlorite is added to convert bromide into bromine. Control of bromide levels should be accomplished to ensure its proper concentration in water. A number of spectrophotometric methods of bromide determination were tested for analysis of cooling water which may contain chlorides, iodides and boric acid as interfering substances. Standard Phenol Red method was found to be inappropriate due to interference from borate. Procedure based on BrCl formation did not give reliable results because of volatility of BrCl compound. Direct detection of bromide based on its self-absorption in UV region suffers from interference of other compounds which demonstrate absorption in the same spectral range. Method which includes triiodide ion formation was found to be most convenient. Cooling water of electric power station was analyzed for bromide using this method and ICP-MS method. Good agreement of results permits to recommend the method of triiodide formation for control of bromide content in waters intended for use in cooling circuits of nuclear power plants.
