# Green Analytical Chemistry--Recent Innovations
## 3 Innovations in Green Analytical Techniques
### Real-Time and In-Process Monitoring  
#### 3.3.1 Advances in Spectroscopic Methods for Real-Time Analysis  
Advances in spectroscopic methods for real-time analysis have revolutionized the field of analytical chemistry, providing sustainable, efficient, and highly sensitive tools for monitoring chemical processes and detecting analytes. These innovations align with the principles of green chemistry by reducing the need for extensive sample preparation, minimizing waste generation, and enhancing energy efficiency. Real-time spectroscopic techniques, such as Raman spectroscopy [63], Fourier-transform infrared (FTIR) spectroscopy [64], and ultraviolet-visible (UV-Vis) spectroscopy [65], have become indispensable in applications ranging from industrial process control to environmental monitoring and medical diagnostics.  
Raman spectroscopy, in particular, has seen significant advancements with the development of portable and miniaturized instruments, enabling real-time, in situ monitoring of chemical reactions and analytes in complex matrices. Techniques like Surface-Enhanced Raman Spectroscopy (SERS) [66] have further increased sensitivity, allowing for trace-level detection of pollutants, biomolecules, and pharmaceutical compounds. Similarly, FTIR spectroscopy has evolved to include real-time monitoring capabilities for gaseous, liquid, and solid samples. Modern FTIR systems equipped with quantum cascade lasers (QCL) offer improved resolution and rapid scanning, making them ideal for real-time monitoring of VOCs and industrial emissions.  
The integration of UV-Vis spectroscopy with flow-through cells and fiber-optic probes has enhanced its application in process analytical technology (PAT) [67], enabling continuous monitoring of reaction progress and product quality in pharmaceutical manufacturing. Advances in chemometric algorithms have further augmented these techniques, enabling real-time data processing, multivariate analysis, and predictive modeling for complex datasets.  
Emerging spectroscopic methods, such as near-infrared (NIR) and mid-infrared (MIR) spectroscopy [68], have also gained traction due to their non-destructive nature and ability to analyze complex biological and environmental samples. NIR spectroscopy, in particular, has found widespread use in agricultural and food quality analysis, allowing for rapid and eco-friendly assessment of moisture content, protein levels, and contaminants [69; 70].  
Coupling spectroscopic techniques with other analytical tools, such as mass spectrometry (MS) and chromatography, has expanded their scope and sensitivity. For instance, laser-induced breakdown spectroscopy (LIBS) and its combination with MS offer unparalleled capabilities for elemental analysis in real time [71]. Portable spectroscopic devices, powered by advancements in photonics and computational technology, have democatized access to real-time analysis, enabling on-site measurements in remote or field settings [72].  
These advances underscore the role of real-time spectroscopic methods as a cornerstone of modern green analytical chemistry. By reducing reliance on consumables, shortening analysis times, and providing immediate feedback, these techniques not only improve efficiency but also contribute to the sustainability and environmental responsibility of analytical workflows. As research continues, the integration of artificial intelligence (AI) and machine learning (ML) with spectroscopic data is expected to further enhance real-time analysis, paving the way for smarter, more adaptive analytical solutions.