Analytical Green Star Area (AGSA) as a new tool to assess greenness of analytical methods

The field of Green Chemistry (GC) and Green Analytical Chemistry (GAC) has led to the development of multiple metrics designed to assess the impact of analytical methods. Among these, the Analytical Eco-Scale (AES) provides a quantitative evaluation but lacks visual representation, limiting intuitive assessment. The Green Analytical Procedure Index (GAPI) and its variant offer graphical evaluation, yet they lack a total scoring system, making direct comparisons difficult. While ModifiedGAPI (MoGAPI) and ComplexMoGAPI provide a total score for each method, their assessment is not directly structured around the principles of GAC, relying instead on 16 and 27 predefined questions, respectively. In contrast, the Analytical GREEnness (AGREE) Metric is explicitly structured around the 12 principles of GAC. However, it does not classify analytical methods based on total scores, is less resistant to user bias, and lacks an analogous metric in GC. To bridge these gaps, the Analytical Green Star Area (AGSA) introduces a comprehensive, built-in scoring, and visually intuitive approach to method evaluation. AGSA integrates method classification, built-in scoring and resistance to user bias, ensuring objective assessment while maintaining alignment with the 12 Principles of GAC. Furthermore, AGSA is an extension of an analogous metric from GC, and is available as an open source at bit.ly/AGSA2025, facilitating interdisciplinary comparisons. Multiple case studies are analyzed, demonstrating its effectiveness in distinguishing analytical methods based on their environmental impact. These findings highlight AGSA as a versatile, consistent, and practical tool for promoting sustainability in analytical laboratories while overcoming the limitations of existing greenness metrics.