Microextraction sample preparation techniques in forensic analytical toxicology

Abstract

Sample preparation is a critical step in forensic analytical toxicology. Different extraction techniques are employed with the goals of removing interferences from the biological samples, such as blood, tissues and hair, reducing matrix effects and concentrating the target analytes, among others. With the objective of developing faster and more ecological procedures, microextraction techniques have been expanding their applications in the recent years. This article reviews various microextraction methods, which include solid-based microextraction, such as solidphase microextraction, microextraction by packed sorbent and stir-bar sorptive extraction, and liquid-based microextraction, such as single drop/hollow fiber-based liquid-phase microextraction and dispersive liquid-liquid microextraction, as well as their applications to forensic toxicology analysis. The development trend in future microextraction sample preparation is discussed.

Determination of tafenoquine in human plasma by dispersive liquid‐liquid microextraction

“…Sample pH is an important parameter in techniques involving analyte partition between aqueous and organic phases, such as DLLME. This factor is optimized according to the analyte, where basic compounds require a high pH to be maintained in the non‐ionized form to dissolve in the droplets of extractor solvent . TQ has basic characteristics (p K a = 10.20) and, therefore, it is expected that a basic medium should facilitate extraction from biological samples.…”

“…The dispersive solvent must be miscible in the sample (aqueous phase) and in the extractor solvent (organic phase) in order to yield a ternary system, which will concentrate analytes in extractor solvent. The mixture obtained by the rapid injection of extractor and dispersive solvents in the sample promotes the dispersion of droplets with high superficial area, in which fast partition occurs . Considering its advantages over traditional techniques of sample preparation, several methods have been reported using this approach lately.…”

Polybrominated Diphenyl Ethers (PBDEs) as Emerging Environmental Pollutants: Advances in Sample Preparation and Detection Techniques

“…Their selectivity enables substantive removal of matrix interferents during the sample pre-treatment step [119]. MIP-based sorbents are readily available substitutes to silica-based adsorbents, which are reported to suffer from matrix interference, low selectivity, and sensitivity towards organic pollutants and may involve multiple steps that are labour-intensive for complete removal of interferences [120]. For example, commercial molecularly imprinted solid-phase extraction (MISPE) cartridges alongside alkaline extraction have been applied in aqueous enrichment and quantitation of PBDEs using GC-MS [121].…”

A review of the bioanalytical methods for the quantitative determination of capecitabine and its metabolites in biological matrices

“…This solvent fills the pores of the HF, after which the inner lumen of the hollow fiber is filled with an acceptor solution. The HF is placed in the sample and extracts the analytes from the sample (Gjelstad & Pedersen-Bjergaard, 2013;He & Concheiro-Guisan, 2019). Recently, it was shown that by modifying HF with sorbents that they can be used for solid-phase microextraction, thereby combining SPME and LPME which is named solid-liquid-phase microextraction (SLPME) (Yang, Chen, & Shi, 2015).…”

“…Extraction techniques are classified as a microextraction if the volume of the extracting phase is very small in relation to the volume of the sample. (He & Concheiro‐Guisan, ). Based on the extraction phase a microextraction method can be classified as solid‐phase microextraction (SPME) or liquid‐phase microextraction (LPME).…”