Towards a universal automated and miniaturized sample preparation approach

Abstract

Nowadays, analytical chemistry plays a fundamental role in developing strategies for monitoring residues and contaminants in complex matrices (e.g., biological, environmental, and food samples). Considering the significant number of interfering substances present, combined with the lower concentration levels in which the target analytes are commonly found, sample preparation is becoming a crucial step in the analytical workflow. For these reasons, automation and miniaturization of this process represent a current trend since by these means, several principles of Green Chemistry can be meet all together, including: (i) lower volumes of reagents and samples required; (ii) reduced waste generation; and (iii) high-throughput with lesser operators' handling. The employment of online sample preparation based on LC systems (e.g., online SPE and In-Tube SPME) can be considered promising tools to perform sample preparation in a more sustainable way than conventional approaches. For these reasons, herein, we present a review discussing the essential characteristics of miniaturized, automated systems, including column-switching modes and modern approaches based on chip-LC. These methodologies deserve attention mainly due to their greener character derived from automation and miniaturization of the process. Also, selected applications, mostly covering the last five years, are presented. A brief comparison between them and conventional LC-based approaches is carried out to bring an adequately discussed review to this journal audience.