Green Sample Preparation Protocols in Analytical Toxicology

Sample preparation is the most critical and challenging step in analytical methodologies, affecting the final greenness of the entire process and largely determining the quality of results obtained. In recent years, the global scientific community has shown an increased interest in developing environmentally friendly analytical protocols with the objective of replacing toxic organic solvents and miniaturization of extraction methodologies resulting in reducing environmental and human hazards. In analytical toxicology, sample preparation becomes more challenging due to the complex nature of samples encountered. Additionally, the sample amount is limited and analyte concentration that needs to be detected is typically low (pg-ng/mL or pg-ng/g range). Recent trends in sample preparation include miniaturization, automation, high-throughput performance, simplicity, sensitivity, sustainability, and affordability by using zero or extremely low amount of toxic solvent. Green sample preparation techniques possess these advantages over the traditional protocols of sample preparation, also complying with the green analytical chemistry demand and ensuring environment protection and public safety.

Owing to the complex nature of biological matrices and potential interferences from endogenous substances, quantitative analysis of drugs, toxic substances and their metabolites is a challenging task. Additionally, the availability of limited amount of samples, as well as phenomena such as postmortem redistribution in cases of forensic toxicology and trace amount of target analytes further complicates the analysis. These complications can be overcome through the wise selection of sample preparation and analytical methods which are sufficiently sensitive and selective. The major goal of this Research Topic is to explore the recent trends in green sample preparation methodologies in the field of analytical toxicology. The focus will be on the development, validation, and application of novel methods for the extraction and quantitative analysis of drugs, toxicants, poisons, and their metabolites in biological matrices, in both therapeutic and toxic levels.

This Research Topic focuses on the application of green sample preparation methodologies in analytical toxicology for detecting drugs, toxicants, poisons, and their metabolites in biological matrices. Various techniques such as sorbent and solvent-based microextraction, on-site sample preparation, smartphone-based colorimetric analysis, and µPAD will be discussed. The main aim of this Research Topic is to promote the development, validation, and practical use of new methodologies that can effectively extract and analyze active drugs, toxicants, poisons, and their metabolites in complex matrices while adhering to green analytical chemistry principles. The use of alternative green solvents that reduce reagent consumption, waste generation, time, and energy in sample preparation are also encouraged. Articles submitted for review must evaluate methods based on analysis quality, cost, time, ease of use, and waste generation, and should be supported by well-documented estimations.

We welcome Original Research, Review, Mini Review and Perspective articles on themes including, but not limited to:
• Sorbent based microextraction: The application of sorptive microextraction techniques such as solid-phase microextraction (SPME), stir-bar sorptive extraction (SBSE), microextraction by packed sorbents (MEPS), thin film microextraction (TFME), fabric phase sorptive extraction (FPSE), capsule phase microextraction (CPME), dispersive solid phase extraction etc. in analytical toxicology. Additionally, the application of natural sorbents (such as cellulose paper, wooden tips, kapok fiber etc) and nanoparticles for extraction of drugs and toxicants.
• Solvent based microextraction: Liquid phase microextraction (LPME), dispersive liquid-liquid microextraction (DLLME), solidification of floating organic droplet – DLLME (SFO-DLLME), homogenous liquid-liquid microextraction (HLLME), ultrasound / vortex-assisted emulsification microextraction (UA/VA-EME) etc. in analytical toxicology. The application of green solvents such as deep eutectic solvents (DES) and ionic liquids (ILs) as extractants in LPME for extraction of drugs and toxicants.
• Colorimetric sensors and smartphone based analysis: The application of colorimetric sensor for drug screening and analysis; point-of-care testing, and detection of biomarkers. The use of smartphone based digital image colorimetry in combination with green sample preparation protocols for determining drug and toxicants in biological samples.
• Microfluidic paper based analytical devices (µPAD): Cost-effective, portable, convenient and possible on-site analysis of drugs and toxicants in biological samples by microfluidic paper based analytical devices.
• Molecularly imprinted polymers (MIPs): Synthesis and application of MIP in sample preparation as a sorbent for selective extraction of drugs and toxicants from complex biological matrices.

Keywords: Green analytical methods, Analytical Toxicology, Microextraction, Green Sample Preparation, Forensic Toxicology, Drug analysis, Bioanalysis

Important Note: All contributions to this Research Topic must be within the scope of the section and journal to which they are submitted, as defined in their mission statements. Frontiers reserves the right to guide an out-of-scope manuscript to a more suitable section or journal at any stage of peer review.