## 4 Discussion  
To use solidified floating organic drop micro-extraction (SFODME) combined with 1-Hexyl-3-methylimidazolium hexafluorophosphate ([HMIM][PF6]) as the ionic liquid without using a chelating agent and subsequent analysis with graphite furnace atomic absorption spectrometry (GFAAS) was applied for the determination of Hg in environmental water samples for the first time and proved to be highly effective. This method leverages the unique properties of [HMIM][PF6], including its low volatility, high thermal stability, and good extraction efficiency for Hg. SFODME helps to separate the mercury preconcentrated phase from the aqueous phase quite practically due to easy freezing of 1-dodecanol close to room temperature. The separation step was as easy as removing the solidified drop over the aqueous phase with an ordinary spatula. The IL-SFODME-GFAAS technique provided remarkable analytical performance, characterized by high sensitivity, a satisfactory enhancement factor, and low detection limits. The data (as summarized in Table 7) clearly indicate that the enhancement factor attained by the proposed method is either superior or comparable to that of other methods reported in the literature. The proposed method stands out due to its several advantages including operational practicality, and cost-effectiveness. Nowadays, scientists give effort to propose more environmentally friendly micro-extraction techniques. The features of this proposed method show compatibility with principles of green chemistry, especially with principle 5 (the use of auxiliary substances (e.g., solvents, separation agents, etc.) should be made unnecessary wherever possible and, innocuous when used), principle 6 (Design for Energy Efficiency), and principle 8 (Reduce Derivatives). The key advantages of this proposed methodology for mercury extraction and determination include very low sample consumption, minimal/no use of toxic organic solvents, meaningful extraction period, being very practical, easily affordable economically, and the fact that it obtained a satisfactory number as an enhancement factor. By the application of this method, mercury analysis in water samples becomes feasible using conventionalGFAAS, even at trace levels. In this proposed study the combination of the ionic liquid and SFODME methods without using chelating agent is used for the first time for metal extraction. Furthermore, the simplicity and rapidity of IL-SFODME-GFAAS facilitate its practical application for routine monitoring of mercury in environmental water samples. If it is desired to test the applicability of the results obtained in this study in different contexts of mercury analysis, some suggestions can be given as tips for applying this preconcentration method for mercury analysis in environmental water samples to other environmental samples. When applying this developed preconcentration method for mercury analysis in environmental water samples to other environmental samples like soil, plants, air, etc., sample preperation steps will be the most crucial and important steps. For soil samples, it is important to homogenize, dry, and reduce the soil samples to an appropriate particle size (e.g., sieving). Chemical dissolving can be performed using acid digestion (e.g., aqua regia or HNO\({}_{3}\)-HCl mixture); however, microwave digestion will be the best option before applying this proposed preconcentration method. For the plant samples, they should be washed, dried, and ground. Suitable solvents (e.g., acids or organic solvents) can be used for chemical digestion, and then this proposed preconcentration procedure can be applied. For air samples, high-volume air samplers can be used. Mercury can be found in solid particulate or gas phases, so sampling devices (e.g., activated carbon