Emerging Tools for Holistic Evaluation of Analytical Methods

The evaluation of analytical methods has changed significantly in recent decades. We have transitioned from a model where aspects such as eco-friendliness were barely considered to the development of software-based metrics designed to assess them. The RGB model, which combines red (analytical performance), green (environmental impact), and blue (practicality), is at the heart of the concept of White Analytical Chemistry (WAC). This triadic approach has helped broaden the field’s focus and offered a more balanced evaluation system. However, analytical science continues to move forward, and with it come new priorities that extend beyond what the RGB framework can fully reflect. This article presents new tools intended to fill that gap. As representative examples, we introduce the Violet Innovation Grade Index (VIGI) and a novel graphical tool for simplifying analytical chemistry method evaluation (GLANCE). The first one is a survey-based visual tool that helps identify the innovative strength of analytical methods; the second one is a template that simplifies the description and reporting of methods. These tools point us toward a future where evaluating analytical techniques can be easier to understand, more transparent, and better suited to the needs of the scientific community.

The way we evaluate analytical methods has come a long way. For a long time, the focus was on whether a method was precise, accurate, sensitive, and reproducible. These were the core pillars that defined a reliable analysis. But today, that’s no longer enough. These classical indicators formed the backbone of validation protocols that guided regulatory acceptance and scientific credibility. However, the emergence of green analytical chemistry (GAC) (1) introduced a necessary expansion in focus, incorporating sustainability, safety, and environmental consciousness into the evaluation of methods. GAC’s 12 principles guided analysts to minimize reagent consumption, reduce toxicity, and favor energy-efficient instrumentation. This movement laid the groundwork for a more comprehensive framework, known as the RGB model (2).When evaluation was organized into red for analytical performance, green for environmental impact, and blue for practicality, the RGB model laid the groundwork for what is now known as white analytical chemistry (WAC) (3). However, as the analytical sciences continue to intersect with data science, miniaturization, and complex regulatory demands, the limitations of the RGB model become evident.

Why RGB is Not Enough: The Need for Broader and Standardized Assessment Tools

Although the RGB framework has been critical in expanding method assessment beyond classical metrics, its scope remains insufficient to address the full range of expectations faced by modern analytical chemists. The development of tools like analytical GREEnness (AGREE) calculator (4) or its sister focused on sample preparation (AGREEprep) (5) for the green dimension, the Red Analytical Performance Index (RAPI) (6) for the red aspects, and the Blue Applicability Grade Index (BAGI) (7) for the blue side, has improved our ability to quantify these criteria. However, these tools often operate in isolation, and there is no widely accepted strategy for combining their outputs or weighting them according to application context. This creates inconsistencies in comparison and interpretation. Furthermore, recent literature has highlighted the importance of adopting standardization frameworks such as the PRISM (practicality, reproducibility, inclusivity, sustainability, and manageability) approach to guide tool development and ensure cross-platform coherence (8). Increasingly, researchers and reviewers require evaluation models that integrate not only methodological parameters but also elements of innovation, digital utility, regulatory compatibility, and pedagogical value. In this sense, the analytical sciences demand an expanded evaluative lens, supported by interoperable metrics and flexible visualizations.

Complementary Tools for the Holistic Evaluation of Analytical Methods

To complement the existing metrics in the context of the RGB model (9), two new tools were recently developed. Firstly, the Violet Innovation Grade Index (VIGI) (10) introduces a novel perspective to method assessment by emphasizing innovation. It integrates 10 distinct criteria: sample preparation and instrumentation, data processing and software, white analytical chemistry and its derivatives, regulatory compliance, materials and reagents, miniaturization, automation, interdisciplinarity, sensitivity, and approach, providing a comprehensive evaluation that complements existing green, blue, and red metrics. Each parameter is evaluated on a three-tiered scale (low, medium, high), generating a pictogram shaped like a 10-pointed star with varying violet intensities. This visual score facilitates rapid interpretation and comparison between methods. Methods incorporating advanced materials, miniaturized devices, and automation scored highly, reflecting their contributions to analytical chemistry. Conversely, methods lacking advanced data processing or interdisciplinary applications scored lower, highlighting areas for potential improvement.

Secondly, the Graphical Layout for Analytical Chemistry Evaluation (GLANCE) (11) is a canvas-based visualization template designed to promote clarity and coherence in the communication of analytical methods. It condenses complex method descriptions into 12 blocks: novelty, target analytes, sample preparation details, reagents used, instrumentation, validation parameters, real sample application, applications of metrics, main results, identified limitations, and any complementary information. GLANCE encourages brevity and focusses by replacing prose with keywords, enhancing both reproducibility and communication. It has proven valuable not only in scientific publications but also in teaching and supervision contexts. In comparative reviews, GLANCE provides a visual summary that can highlight strengths and gaps across multiple methods, facilitating transparent decision-making.

Among the most established tools are AGREE (4) and AGREEprep (5) which use visual pie charts to communicate adherence to the principles of GAC. These tools allow analysts to identify specific weaknesses in environmental performance. RAPI (6) provides a systematic approach to evaluate red attributes such as selectivity, sensitivity, and precision. BAGI (7) is mainly focused on the practical aspects. Some recent innovations in this context include tools like Green Wine Analytical Procedure Evaluation (GWAPE) (12), Greenness Evaluation Metric for Analytical Methods (GEMAM) (13), Analytical Green Star Area (AGSA) (14), Click Analytical Chemistry Index (CACI) (15), Carbon Footprint Reduction Index (CaFRI) (16), and Battery Efficiency and Performance Scoring Index (BEPSI) (17) (see Figure 1). Though not yet widely adopted, these tools reflect the ongoing diversification of evaluation priorities. Moreover, given the wide variety of metrics and tools available in the field of analytical chemistry, some authors have shown interest in conducting literature reviews focused on this topic (18-20) or in applying several of these tools in their research projects (21).

Synergies and Integration: Towards a Unified Framework

The expanding range of tools for evaluating analytical methods shows that the scientific community is active, curious, and willing to improve. Still, the lack of a common or connected framework makes it harder to bring everything together and move forward as a whole. It can be stated that over the past five years, there has been a remarkable boom in the development of metrics in analytical chemistry, particularly those aimed at assessing the environmental sustainability of methods. While this reflects a growing interest in sustainability, it has also led to a proliferation of overlapping tools, such as AGREE, GEMAM, and AGSA, all of which attempt to evaluate “similar aspects”. This abundance can be both confusing and overwhelming for chemists, as it becomes difficult to determine which metric offers the most reliable or comprehensive assessment for a given application.

Furthermore, many tools provide standalone assessments without compatibility or integration pathways. This fragmentation leads to inefficiencies in peer review, regulatory compliance, and method comparison. To move toward a unified system, developers and users of analytical metrics must collaborate on establishing shared guidelines, data standards, and visualization formats. The PRISM framework offers a promising starting point (8). Tools should be adaptable to the specific needs of each context while still being built on algorithms that are clear, consistent, and easy to reproduce. A flexible platform, ideally with the help of artificial intelligence (AI), could enable users to enter details about their analytical methods and receive a comprehensive evaluation that encompasses innovation, performance, sustainability, and ease of use. If it also included educational resources, it would be a valuable learning tool for students and early-career researchers trying to grasp how these evaluations work. Journals and funding agencies could also benefit, using the platform to simplify submissions and reviews while promoting greater transparency and stronger scientific standards across the field.

Conclusions

Analytical chemistry is at a crucial moment, where the need to be responsible and the drive to innovate need to come together to shape the future of the field. The emergence of tools like VIGI and GLANCE reflects a shift toward more inclusive, visual, and multidimensional frameworks for evaluating analytical methods. These instruments complement the RGB model by adding depth and adaptability, aligning method assessment with the realities of modern science. Soon, we anticipate the development of digital dashboards, interactive-based interfaces, and AI-supported scoring algorithms. These tools will enable real-time evaluation and dynamic updating of method profiles. Bringing these tools together with open-access databases and collaborative platforms could help the scientific community make smarter, more informed decisions by sharing knowledge and experiences. The primary aim is to develop a system for evaluating methods that is clearer, more adaptable, and consistent; one that can support researchers, teachers, professionals, and decision-makers alike.

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Adrián Fuente-Ballesteros, Ana Jano, Ana M. Ares, and José Bernal are with the Analytical Chemistry Group (TESEA) of I. U. CINQUIMA, Faculty of Sciences, at the University of Valladolid, in Valladolid, Spain. Shaikh Manirul Haque is with the Industrial Chemistry Division of the Department of Chemical Engineering at Jubail Industrial College, in Jubail Industrial City, Saudi Arabia. Ebaa Adnan Azooz is with the Chemistry Department at The Gifted Students' School at the Najaf Ministry of Education, in Najaf, Iraq, and the Radiological Technology Department of the College of Medical Technology at The Islamic University, in Najaf, Iraq. Direct correspondence to: adrian.fuente.ballesteros@uva.es