Trends in Innovations and Recent Advances in Membrane Protected Extraction Techniques for Organics in Complex Samples

Abstract

Membrane protected extraction is an ongoing innovation for isolation and pre-concentration of analytes from complex samples. The extraction process, clean-up and pre-concentration of analytes occur in a single step. The inclusion of solid sorbents such as molecularly imprinted polymers (MIPs) after membrane extraction ensures that selective double extraction occurs in a single step. The first step involves selective extraction using the membrane and diffused analytes are trapped on the solid sorbent enclosed in the membrane. No further clean-up is required even for very dirty samples like plant extracts and wastewaters samples. Sample clean-up occurs during extraction in the first process and not as additional step since matrix components are prevented from trapping on the sorbent. This can be referred to as prevention is better than cure approach. In this work, the analytical methods that employed membrane protected extraction for various organics such as pesticides, polycyclic aromatic hydrocarbons, and pharmaceuticals are reviewed. The designs of these analytical methods, their applications, advantages and drawbacks are discussed in this review. Literature suggests that the introduction of solid sorbents in membrane creates the much-needed synergy in selectivity. Previous reviews focused on membrane combinations with MIPs while discussing micro-solid-phase extraction. The scope of this review was broadened to include other sample preparation aspects such as membrane protected stir bar solvent extraction and membrane protected solid-phase microextraction. In addition, novel sample preparation methods for solid samples which include Soxhlet membrane protected molecular imprinted solid phase extraction and membrane protected ultra sound assisted extracted are discussed.

Keywords:

• Complex samples
• membrane protected extraction
• organic compounds
• porous membrane
• sorbents

Acknowledgments

The authors would like to thank National Research Foundation of South Africa and Water Research Commission for having funded some of the research cited performed in our laboratory over the past years.

Disclosure statement

The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.

CRediT authorship contribution statement

Lawrence Mzukisi Madikizela: Conceptualization, Literature search and interpretation, Co-Writing the original draft. Hlanganani Tutu: Conceptualization and final editing the manuscript. Ewa Cukrowska: Conceptualization and final editing of the manuscript. Luke Chimuka: Conceptualization, literature search and interpretation, and editing the final manuscript.

Data availability statement

The authors confirm that the data supporting the findings of this study are available within the article.