Are Microextraction Techniques Truly Green? A Critical Assessment of Green Sample Preparation Practices.

The development of sample preparation methods has led to smaller versions of traditional solid- and liquid-based techniques. This trend aims to align these methods with green analytical chemistry principles by reducing sample and solvent use and enabling more flexible designs, including online and automated systems. However, although miniaturization is often linked to environmental benefits, it also presents significant issues that are sometimes overlooked. These include the continued use of toxic solvents, labor-intensive procedures, and potential health and environmental risks that may be underestimated in the pursuit of "green" solutions. Therefore, this review offers a comprehensive and current overview of both solid- and liquid-based miniaturized techniques, emphasizing their environmental challenges. It focuses on balancing analytical performance with core green chemistry principles. Selected examples from recent literature highlight current applications and trends. Additionally, we discuss emerging directions and ongoing challenges that must be addressed to truly achieve sustainable, green implementation of these methods. We hope this review encourages a more critical perspective among readers and promotes the development of genuinely greener sample preparation strategies across different analytical applications.