Novel Salt-Assisted Liquid-Liquid Microextraction Technique for Environmental, Food, and Biological Samples Analysis Applications: A Review

Abstract

Background: Sample preparation has gained significant recognition in the chemical analysis workflow. Substantial efforts have been made to simplify the comprehensive process of sample preparation that is focused on green sample preparation methodology, including the miniaturization of extraction method, elimination of the sample pre-treatment as well as the post-treatment steps, elimination of toxic as well as hazardous organic solvent consumption, reduction in sample volume requirements, reducing the extraction time, maximization of the extraction efficiency and possible automation. Methods: Among various microextraction processes, liquid-phase microextraction (LPME) is most abundantly used in the extraction of the target analytes. The salting-out phenomenon has been introduced into the LPME procedure and has been raised as a new technique called the ‘Salt-Assisted Liquid-Liquid Microextraction (SALLME)’. The principle is based on decreasing the solubility of less polar solvent or analyte with an increase in the concentration of the salt in aqueous solution leading to two-phase separation. Conclusion: SALLME is mainly based on the salting-out phase separation phenomenon. It is important to optimize the SALLME experimental parameters, such as solvent volume, salt amount, and extraction time, to achieve the maximum extraction capacity of the target analytes from the sample matrices. Conclusion: SALLME proved to be a simple, rapid, and cost-effective sample preparation technique for the efficient extraction and preconcentration of organic and inorganic contaminants from various sample matrices, including environmental, biological, and food samples. SALLME exhibits higher extraction efficiency and recovery and is compatible with multiple analytical instruments. This review provides an overview of developments in SALLME technique and its applications to date.