# Green Analytical Chemistry--Recent Innovations
## 4 Application of Green Solvents
For industries and researchers looking to minimize their ecological footprint, SC-CO\({}_{2}\) provides a practical and scalable solution. [PERSON] et al. [80] developed an ultra-high-performance supercritical fluid chromatography (UHPSFC) method utilizing supercritical carbon dioxide (SC-CO\({}_{2}\)) as a green mobile phase for the analysis of complex plant extracts. This approach enabled the efficient separation of volatile terpen, flavonoids, and phenolic acids within a single chromatographic system, eliminating the need for traditional gas and liquid chromatography. By replacing hazardous organic solvents with SC-CO\({}_{2}\) and minimal organic modifiers, the method significantly reduces solvent waste and aligns with green chemistry principles. Additionally, the recyclability of SC-CO\({}_{2}\) enhances its sustainability, making it an attractive alternative for environmentally friendly analytical applications. The study highlights the potential of supercritical fluids in green chromatography, offering a high-throughput and scalable solution for complex sample analysis. Similarly, ionic liquids (ILs) have emerged as promising green solvents due to their versatility and customizable properties. These designer solvents can be tailored for specific tasks, such as extracting metals, purifying pharmaceuticals, or analyzing environmental pollutants. Their stability and effectiveness in challenging conditions make them an attractive alternative to conventional solvents. [PERSON] et al. [81] demonstrated the effectiveness of ionic liquids (ILs) as mobile phase additives in HPLC analysis. By incorporating 1-butyl-3-methylimidazolium tetrafluoroborate (BMIM[BF4]) and 1-butyl-3-methylimidazolium hexafluorophosphate (BMIM[PF6]) into a water:acetonitrile mobile phase, the study achieved enhanced separation of nicotine and cotinine in biological samples. ILs improved peak shape, minimized interactions with silanol groups, and reduced the need for toxic organic modifiers. Their low volatility and recyclability further highlight their potential as green alternatives in liquid chromatography. As green analytical chemistry advances, the use of task-specific ionic liquids (TSILs) continues to offer tailored, efficient, and environmentally conscious solutions. In recent years, task-specific ionic liquids (TSILs) have pushed the boundaries even further, allowing for solutions that are both efficient and environmentally conscious. A novel approach utilizing task-specific ionic liquids (TSILs) nanoconfined in nitrogen-doped porous carbon (ILs@PC) was developed recently to improve the detection and adsorption of sulfonamide antibiotics (SAs) in environmental and food samples [82]. This method eliminates the need for hazardous organic solvents by leveraging functionalized ILs tailored for selective solid-phase extraction (DSPE). Whencombined with high-performance liquid chromatography (HPLC-UV), the system achieved low detection limits (0.75-1.88 \(\upmu\)g L\({}^{-1}\)) and high recoveries (86.0-111.9%). To further enhance practicality, a portable syringe-based device was introduced for on-site rapid testing, demonstrating the scalability of IL-based methods in green analytical chemistry. This study highlights the growing role of TSILs as effective, environmentally friendly alternatives to conventional extraction solvents. Bio-based solvents, derived from renewable resources like plants and sugars, are another exciting development. Not only are they biodegradable and less toxic than their petroleum-based counterparts, but they also perform exceptionally well in applications like liquid-liquid extraction and chromatography. A notable example is glycerol, a natural and renewable trihydric alcohol derived from plant and animal sources, which has been successfully applied as a mobile phase modifier in reversed-phase HPLC. [PERSON] et al. [83] demonstrated that a glycerol-phosphate buffer (7:93 \(v/v\)) mobile phase effectively separated four antiviral drugs while minimizing the need for hazardous organic solvents.