Current Analytical Chemistry - Volume 19, Issue 2, 2023

Background: Removing heavy metal ions and various organic contaminants from water (surface water, groundwater, drinking water, and wastewater) using inexpensive and readily available adsorbents is essential in all environmental and human aspects. This study aims to explore the various adsorbents with a particular emphasis on polymeric adsorbents for their applications in the removal of heavy metal ions and emerging contaminants from water. Methods: A brief review as a perspective article on polymeric adsorbents with a particular emphasis on their applications in water treatment, consequences, challenges, and relevant issues/ perspectives that need to be resolved in the future is highlighted. Results: Due to the increasing global human population with rapid urbanization, industrialization, and environmental change, removing heavy metals and emerging contaminants from water fonts has become a primary environmental concern and a huge challenge to ensure safe water supplies. This directs an utmost demand to develop various water treatment and recycling methods. Different types of adsorbents, including polymeric adsorbents, have also been discussed. The study indicates the presence and structural behaviors (e.g., functional groups, degradation, adsorption, desorption), adsorption-desorption process, regeneration, safe removal and disposal procedure, and toxicity of the adsorbents are vital to use them safely for an extended period in the application of water treatment. Conclusion: A brief discussion on adsorption, methods, various types of polymeric adsorbents, and their applications for removing organic and/or heavy metal contaminants from water and wastewater is presented in this review as a perspective article. A better understanding of the preparation of polymers from inexpensive, readily available, natural sources and toxicity issues is still needed to be considered, particularly in the human-related exposure and relevant risk on the water and wastewater treatment.

The rapid and accurate identification of pathogens plays a crucial role in clinical practice, which helps to prevent, control, and treat pathogenic infections at the initial stage. The current available technologies for pathogen detection appear to be inadequate in dealing with cases such as COVID-19. More importantly, the frequent emergence of drug-resistant bacteria is gradually rendering the existing therapeutic options ineffective. Efforts are urgently required to focus on the development of diagnostic systems for point-of-care (POC) detection and high-throughput pathogen identification. Since 2001, a new class of aggregation-induced emission luminogens (AIEgens) with good photostability, high sensitivity, and improved signal-to-noise ratio has emerged as powerful fluorescent tools for various biosensing and cell imaging. Based on the unique fluorescence of AIEgens that becomes stronger upon aggregation, naked-eye detection in turn-on mode has gained a speedy development. A timely overview can not only provide a summary of the advances and challenges of AIEgens in pathogen detection but also offer systematic ideas for future developments. There are also expectations for in-depth interdisciplinary research in the field of analytical chemistry and microbiology.

Sericin is a serine-rich polydispersed glycoprotein found in Bombyx mori's cocoons. Sericin is extracted from cocoons as a protein, composed of amino acids like aspartic acid, glycine, tyrosine, serine, and glutamic acid with carboxyl, hydroxyl, and an amino group. Sericin has been explored for various pharmacological activities, such as antioxidant, anti-inflammatory, antiapoptotic, antiproliferative, antibacterial, anti-hypercholesteremia, and wound healing activity. Moreover, sericin has also been explored as a biopolymer for the preparation of nanoparticles, scaffolds, hydrogels, films, etc. This mini-review illustrates the reported methods for the characterization of extracted sericin and quantification in pharmaceutical formulations. The review covers analytical methods like UV-Visible Spectroscopy, Fouriertransform infrared spectroscopy, amino acid analysis, mass spectroscopy, and high-performance liquid chromatography with a brief explanation of every analytical method.

Pharmaceutical preparations contain at least one active pharmaceutical ingredient and a wide range of excipients, each with a defined pharmaceutical purpose. India is known as the pharmacy of the world (manufacturing generic drug products). The market demand of generic products is increasing exponentially throughout the Asian and African regions. To satisfy the general population needs and competition in the market, specific tools need to be there in the generic manufacturing unit that can fulfill the need of generic manufactures in cracking the branded medicinal and nutritional products. This review aims to present reverse engineering techniques that have been found beneficial in qualitative and quantitative analysis. The diversity of techniques and their uses in generic product development have been reviewed here. This was a supposed idea to provide the generic manufacturers with an analytical tool set that can make generic product development easier and provides several examples of excipients that have been identified to crack the drug composition.

Atypical antipsychotics have gained incredible attention over the last decade and are widely prescribed for short-term and chronic treatment of various psychopathological diseases, including schizophrenia, mania, delirium, bipolar disorder, depression, autism spectrum disorder, and affective disorders. Due to their better clinical profile and therapeutic benefits, atypical antipsychotics have become a better choice for psychopathological treatment and management. However, their usage is associated with peripheral side effects and metabolic diseases impacting the quality of life of patients. In the sight of these circumstances, strategic development of analytical methods to isolate atypical antipsychotics from a variety of formulations and biological samples and identify and quantify them with great sensitivity and accuracy is of great importance in clinical and forensic settings. In the present review, we have summarized and discussed various analytical methods reported in the literature over the last decade in various formulations and biological samples, highlighting analytical trends to the analysts in the field of atypical antipsychotics.

Background: A new technique was designed for determining copper in an aqueous solution. Copper was determined by a hybrid system microfluidic coupled with flow injection. The homemade microfluidic chip (MFC) is used for injecting copper and 2,9-Dimethyl-1,10-phenanthroline (2,9 DMP) reagent as a merging zone technique, whereas uric acid is used as a reducing agent and carrier. Methods: A microfluidic chip was made by a Computer Numerical Control (CNC) laser machine using the AutoCAD application for the study of copper by the hybrid system. The chip contains two microchannels with a volume of 60 μL for copper(II) and 2,9 DMP reagent. As a carrier solution and reducing agent, 40 mg/L of uric acid was pumped at a flow rate of 5.2 mL/min. Conditions of the coupled technique and analyses were measured at 454 nm. Results: This system's approach has a linear range, a detection limit (S/N = 3), and a quantitation limit (S/N = 10) at 0.1-25 mg/L (r² 0.9979), 0.03 and 0.09 mg/L, respectively. Also, there was a repeatability of analyses (n = 7) with an average RSD of 0.97 % for concentrations of 5, 10, and 20 mg/L. The dispersion coefficients were 1.977, 1.789, and 1.555 for the three concentrations 5,10, and 20 mg/L, respectively. The recovery of copper in the aqueous solution was estimated to be 103.5%. Dead volume and throughput were zero and 62 per hour, respectively. Sandell’s sensitivity and molar absorptivity were 2.467×10^-3 μg/cm² and 1.947×10⁵ L/mol cm, respectively. Conclusion: The analysis in the novel hybrid microfluidic-flow injection system is efficient, simple, and fast, and it can be used to determine the concentration of copper in an aqueous solution. The homemade microfluidic chip is a low-cost component that uses only an small volume of copper and reagent during analysis.

Background: Nowadays, plastic accumulation in marine has become one of the topics of global concern, with emerging research efforts focusing on the threat of microbeads (<5mm). A source of microplastic pollution is derived from personal care products (facial cleanser) that contain polyethylene microplastic (microbeads), which are not captured by the wastewater treatment plant. These small particles are especially concerning because of their potential to translocate in the bodies of organisms. Methods: Herein, we have used a mixture of hydrogen peroxide with nitric acid to dissolve the organic matter before the filtration and filtration was carried out by using Whatman filter paper 42 to ascertain that all the microbeads had been collected. Collected microbeads were identified using Fouriertransformed infrared spectroscopy (FT-IR) and stereo microscope. Results: In this study, we have observed that personal care products contain microplastic beads, and that three out of six personal care products contain a polyethylene (PE) bead. Conclusion: We have provided a feasible separation and analysis method for microplastic beads in personal care products.

Introduction: A simple and inexpensive differential calorimetric sensor for rapid hydrogen peroxide (H2O2) quantification in industrial solutions was developed, characterized and validated. An earlier method proposed by the authors, on which the developed sensor is based, was enhanced, allowing overcoming the issues with its practical application. Thus, the following goals were achieved: a response time of 195 s from sampling to the analytical result; the elimination of the influence of initial sample temperature on the precision of the result by a differential mode of measurement application; the elimination of the result precision degradation caused by the parasitic heat produced by the sample stirrer. A linear quantification range from 0.05 to 1.5 mol L^-1 H2O2 with a limit of detection (LOD) of 0.035 mol L^-1 H2O2 was reached by applying disposable catalyst holders with a lifetime of more than 50 quantifications. The catalyst surface area to sample volume ratio adjustment allows the sensor’s analytical characteristics adaptation to the industrial-technological process requirements. Background: Hydrogen peroxide is used as a reagent in the technological processes of several industrial branches, and the simple and fast monitoring of its concentration is critical for the maintenance of technological process stability. The common disadvantages of the existing sensors are the complex and long measuring procedures requiring sophisticated equipment and qualified personnel. Objective: This study’s objective is the development of a simple and inexpensive calorimetric sensor and measuring instrument for rapid H2O2 quantification in industrial solutions by nonqualified personnel. The sensor is based on the significant improvement of the reagent-less calorimetric method proposed by the authors earlier, allowing its simple and precise practical application. Drawbacks such as the result of precision degradation by the initial sample temperature and by parasitic heat production during the measurement were overcome by obtaining an economical, simple, rapid, and precise sensor. Methods: The temperature increase resulting from the heat generated during the catalytic H2O2 decomposition was recorded as a sensor response. A simple and inexpensive disposable acrylic ring covered by MnO2 serves as a specific catalyst for H2O2 decomposition. The sensor analytical characteristics were evaluated, and permanganate approach validation was conducted. Results: The developed sensor showed a linear response to H2O2 from 0.05 to 1.5 mol L^-1 with a LOD of 0.035 mol L^-1 and LOQ of 0.115 mol L^-1 under optimized experimental conditions. The catalyst surface area to sample volume ratio adjustment allows the sensor’s analytical characteristics adaptation to the industrial process requirements. The results were validated using the permanganate approach application, obtaining recovery values of 98.7%-101.4%. Conclusion: A simple and economic calorimetric sensor for quick hydrogen peroxide quantification in industrial solutions was developed, characterized, and validated. Disposable catalyst-loaded rings were employed allowing 50 successive quantifications of 1 mol L^-1 H2O2 with a relative error of 1.08%. The sensor construction enables easy catalyst replacement and adjustment of its analytical characteristics to the industrial technology requirements using catalyst rings with various catalyst surface areas.