# Green Analytical Chemistry--Recent Innovations
## 4 Application of Green Solvents  
_Use of Water, Supercritical Carbon Dioxide, Ionic Liquids, and Bio-Based Solvents in Analytical Processes_  
The use of water, supercritical carbon dioxide (SC-CO\({}_{2}\)), ionic liquids (ILs), and bio-based solvents in analytical processes reflects a meaningful step toward more sustainable and environmentally friendly practices [76; 77]. Water, often called the universal solvent, has become a cornerstone of green analytical chemistry. Its non-toxic, abundant, and cost-effective nature makes it an excellent alternative to hazardous organic solvents. Techniques like water-based extractions and aqueous chromatographic systems have shown that water is not just eco-friendly, it is also highly effective in separating biomolecules, pharmaceuticals, and environmental pollutants. [PERSON] et al. [78] developed a solvent-free micellar HPLC \begin{table}
\begin{tabular}{c c c c} \hline \hline
**Industry** & **Application** & \begin{tabular}{c} **Example** \\ **Companies** \\ \end{tabular} & **Green Alignment** \\ \hline Environmental & \begin{tabular}{c} Detect heavy \\ metals, greenhouse \\ gases, air quality \\ \end{tabular} & \begin{tabular}{c} Sensorix, Figaro \\ USA Inc., \\ Cambridge \\ Sensotec \\ \end{tabular} & \begin{tabular}{c} Reduces pollution, \\ real-time \\ monitoring \\ \end{tabular} \\ \hline Agriculture & \begin{tabular}{c} Soil moisture, \\ nutrient levels, \\ plant health \\ \end{tabular} & \begin{tabular}{c} Multi Nano Sense \\ Technologies \\ \end{tabular} & \begin{tabular}{c} Optimizes resource \\ use, reduces waste \\ \end{tabular} \\ \hline Medical/ \begin{tabular}{c} Mechanical/ \\ Pharmaceutical \\ \end{tabular} & \begin{tabular}{c} Sweat chloride, \\ drug degradation \\ kinetics \\ \end{tabular} & \begin{tabular}{c} Sensirion AG, \\ Cambridge \\ Sensotec \\ \end{tabular} & \begin{tabular}{c} Supports \\ sustainable \\ healthcare, low \\ waste \\ \end{tabular} \\ \hline Food Industry & \begin{tabular}{c} Detect \\ contaminants like \\ dyes, monitor \\ storage conditions \\ \end{tabular} & \
\begin{tabular}{c} Figaro USA Inc., \\ Sensirion AG \\ \end{tabular} &
\begin{tabular}{c} Enhances food \\ safety, reduces \\ chemical use \\ \end{tabular} \\ \hline \hline \end{tabular}
\end{table} 
Table 3: Industrial applications of electrochemical sensors in green analytical chemistry, highlighting key sectors, specific applications, example companies, and their contributions to sustainability. method for antidiabetic drug analysis, replacing hazardous organic solvents with water as the primary solvent. Using Brij-35 and SDS, the method forms a micellar environment that enhances separation efficiency while minimizing VOC emissions and solvent waste. Its GAPI and AGREE assessments confirm superior sustainability compared to conventional reversed-phase HPLC. This study highlights the potential of water-based solvent systems in advancing green chromatography. In another work by [PERSON] et al. [79], a sustainable HPLC method was developed using a water-based mobile phase consisting of ethanol (63%) and an aqueous phosphate buffer (37%), adjusted to pH 3.0. This method eliminates the need for hazardous organic solvents like acetonitrile and methanol, making it an environmentally friendly alternative for pharmaceutical analysis. With a short analysis time of 5 min, reduced solvent consumption, and improved Eco-scale and AGREE scores, this approach demonstrates the effectiveness of water-based solvent systems in advancing green analytical chemistry while maintaining high analytical performance. Similarly, supercritical carbon dioxide has also gained recognition for its unique properties. Acting as both a solvent and a mobile phase, SC-CO\({}_{2}\) offers exceptional separation capabilities without the harmful environmental impacts associated with traditional solvents. It is widely used in the extraction of natural products like essential oils and pharmaceuticals, and its recyclability makes it even more appealing.