https://dspace.iiti.ac.in/handle/123456789/3647 2026-10-16T08:22:17Z https://dspace.iiti.ac.in/handle/123456789/19439 Title: Vortex-Assisted Floating Organic Drop Microextraction Coupled with Flame Atomic Absorption Spectrometry for Sensitive Determination of Trace Nickel in Food Samples Authors: Dubey, Mrigendra (59096504600) Abstract: A vortex-assisted dispersive liquid–liquid microextraction based on solidification of a floating organic drop (VA-DLLME-SFOD) coupled with flame atomic absorption spectrometry (FAAS) was developed for the preconcentration and determination of trace Ni(II) in water and canned-food samples. Ni(II) was complexed with 1-(2-pyridylazo)-2-naphthol (PAN), and the resulting hydrophobic complex was extracted into 1-undecanol. Seven experimental factors were initially screened using a Plackett–Burman design, identifying sample volume, PAN concentration, and dispersive-solvent type as significant variables. Because dispersive-solvent type is categorical, separate circumscribed central composite designs were evaluated for methanol and tetrahydrofuran (THF), with THF providing the more suitable extraction system. The optimized procedure employed a 12.0 mL sample at pH 9.0, 100 μL of 1-undecanol containing 2.273 mM PAN, 0.50 mL THF, and 3 min vortex-assisted extraction. Under these conditions, the method showed a linear range of 0.038–0.125 mg L⁻1 with R2 = 0.9991. The limits of detection and quantification were 0.011 and 0.038 mg L⁻1, respectively. An enrichment factor of 9.08, a preconcentration factor of 12.0, and an extraction efficiency of 75.68% were obtained. The relative standard deviation was 3.5% at 0.125 mg L⁻1 Ni(II). The proposed VA-DLLME-SFOD–FAAS method was successfully applied to the determination of nickel in surface water, tap water, drinking water, and canned food samples. Recovery values ranging from 85 to 113% demonstrated the accuracy and suitable of the method for the analysis of real samples. The proposed procedure combines low organic-solvent consumption, vortex-enhanced mass transfer, convenient solidification-assisted phase collection, and multivariate optimization in a simple sample-preparation platform. © The Author(s), under exclusive licence to Springer Science+Business Media, LLC, part of Springer Nature 2026. 2026-01-01T00:00:00Z https://dspace.iiti.ac.in/handle/123456789/19425 Title: Key Electrode Materials for Solid-State Batteries Authors: Krishnan, Sarathkumar (57205489071); Singh, Mayank K. (57220086970); Rai, Dhirendra Kumar (56262900200) Abstract: Solid-state batteries (SSBs) are considered a next-generation energy storage technology due to their potential to enhance safety and increase energy density as compared to conventional liquid-electrolyte-based lithium-ion batteries (LIBs). This chapter explores the key electrode materials and properties that are essential to the performance of SSBs, emphasizing their critical role in determining specific capacity, rate performance, and stability. This chapter starts with an introduction to electrode processes, outlining the fundamental mechanisms of ion transport and electron transfer. The discussion progresses to the critical properties and requirements for electrode materials that are suitable for SSBs. With a major focus on lithium-ion batteries, the chapter explores the advancements and possible challenges in cathode materials, particularly intercalation and conversion-type electrode materials, which offer significant improvements in energy density and cyclic stability. On the anode side, the chapter investigates the potential of metal anodes, carbon materials, and alloy anodes, particularly highlighting their performance and the problems they face in practical applications. The chapter also discusses the broader challenges faced by SSB technology with anodes, including poor ionic conductivity, interface compatibility, and dendrite formation. Finally, we expand our scope to other alkali-metal ion batteries, such as sodium (Na+) and potassium (K+), discussing their unique advantages and future research directions. Through a comprehensive review of recent advancements and ongoing research challenges, this chapter provides valuable insights into the key materials and strategies that will drive the future of solid-state battery technology, paving the way for building state-of-the-art energy storage technologies. © The Author(s), under exclusive license to Springer Nature Singapore Pte Ltd. 2026. 2026-01-01T00:00:00Z https://dspace.iiti.ac.in/handle/123456789/19438 Title: Smartphone-Based Digital Image Analysis (DIA) for Rapid Determination of Pyraclostrobin in Water and Vegetable Samples Authors: Dubey, Mrigendra (59096504600) Abstract: An efficient and user-friendly smartphone-based digital image analysis (DIA) method was developed for the determination of pyraclostrobin residues in water and vegetable samples. The proposed method is based on a diazotization–coupling reaction, in which pyraclostrobin has been converted into a stable azo dye, enabling quantitative analysis by both conventional UV–Vis spectrophotometry and smartphone-assisted DIA. The developed approach offers a practical alternative for rapid pesticide residue screening, particularly for field-based and resource-limited applications. The analytical performance of both methods was systematically evaluated in terms of linearity, limit of detection (LOD), limit of quantification (LOQ), precision, and recovery. The UV–Vis spectrophotometric method showed a linear response over the concentration range of 0.21–1.00 mg L⁻1, with LOD and LOQ values of 0.06 and 0.21 mg L⁻1, respectively, and excellent repeatability with a minimum %RSD of 0.93%. The smartphone-based DIA method, using the green (G) color channel for quantification, achieved LOD and LOQ values of 0.09 and 0.32 mg L⁻1, respectively, with satisfactory precision (%RSD = 2.88%). The applicability of the proposed methods was validated using real samples, including surface water, tap water, drinking water, and vegetable matrices. Recovery values ranged from 86.0 to 104.0% for the UV–Vis method and 95.0–120.0% for the smartphone-based DIA method. These results demonstrate that the proposed smartphone-assisted DIA method provides a reliable, portable, cost effective and accessible platform for rapid pyraclostrobin residue primary screening in environmental and food samples, showing strong potential for on-site monitoring and food safety applications. © The Author(s), under exclusive licence to Springer Science+Business Media, LLC, part of Springer Nature 2026. 2026-01-01T00:00:00Z https://dspace.iiti.ac.in/handle/123456789/19407 Title: Influence of sample positioning and solution volume on distinguishing sonolysis from piezocatalysis in ultrasonic dye degradation Authors: Singhal, Mohit (60080486100); Gaur, Akshay (57656581700); Nagar, Brajesh Kumar (60883309200); Singh, Dhiraj Kumar (60539000900); Patel, Satyanarayan (56041315300) Abstract: Piezocatalysis has emerged as an optimistic mechanically assisted catalytic process for the degradation of organic pollutants, in which ultrasonic waves stimulate the piezoelectric material and activate its catalytic activity. Laboratory-scale piezocatalytic investigations commonly utilize an ultrasonicator, which produces a spatially varying acoustic field, while sonolysis, contributes to variations in degradation efficiency. The radicals produced through sonolysis also contribute to pollutant degradation, thereby introducing uncertainty in the assessment of the piezocatalyst's apparent piezocatalytic activity. The present study investigates the contribution of sonolysis in the piezocatalysis process by examining degradation at various locations within the ultrasonicator. The outcomes of the study demonstrate that there is inconsistency in degradation with spatial positioning. Furthermore, a critical minimum pollutant volume was identified above which consistent results were obtained for sonolytic dye degradation. The findings from the investigations strongly recommend mandatory steps of optimizing sample positioning and pollutant volume prior to any piezocatalytic investigation that need to be followed to ensure repeatability and isolate sonolysis contributions. © 2026 The Author(s) 2026-01-01T00:00:00Z