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Reliable assessment of the health and environmental risk associated with the use of chemicals is critical to objectively evaluate the greenness and whiteness of an analytical method. An objective and useful way of risk assessment should take into account all the relevant properties of used substances, their actual amounts needed for application of the method, and quantify the assessment result using a standardized unit. This article presents a relatively simple approach to meet the above requirements, which we call the Chloroform-oriented Toxicity Estimation Scale (ChlorTox Scale). The risk posed by a given substance is expressed by the ChlorTox value, and the sum of the values obtained for all reagents is the overall risk posed by the method (Total ChlorTox). The ChlorTox value is calculated by comparing the hazards for the substance being assessed to the standard – chloroform, using the approach selected by the user as optimal, taking into account the amount of a pure substance needed for single analysis. The ChlorTox unit is the equivalent mass of chloroform which reflects the estimated degree of predicted risk. This tool can be used for risk assessment in laboratories of various profiles.

Sample preparation is a key step in the analytical procedure and a critical component for achieving analytical greenness. AGREEprep is the first metric intended for evaluating the environmental impact of sample preparation methods. The approach consists of ten steps of assessment that correspond to the ten principles of green sample preparation and uses a user-friendly open-source software to calculate and visualize the results. Despite the simplicity of the approach, some assessment steps can be difficult to evaluate in a straightforward manner, either because essential data are not readily available or, in some cases, are poorly defined.This walkthrough tutorial on AGREEprep serves as an in depth yet simple guide for new users that elucidates all aspects of the greenness assessment. It will prove beneficial to analysts wishing to assess the greenness of their own developed procedures or those found in the literature, which can be challenging taken that critical data is often not reported. Particular attention is given to the calculations involved in estimating the amount of waste generated and energetic requirements. The impact of weight values of criteria on the overall final score are discussed and using two hypothetical scenarios is related to the analytical goals of operators. Finally, several assessment examples are given in the supplementary information to familiarize assessors with all assessment steps.