Green sorbents in sample preparation techniques - naturally occurring materials and biowastes

For years, scientists have been trying to develop sustainable, environmentally friendly methods of extraction and determination of trace environmental pollutants that take into account the principles of Green Analytical Chemistry (GAC). It is important to save energy and time, minimize and automate individual stages of sample preparation for determination, and significantly reduce or completely eliminate harmful wastes and solvents from the analytical procedure. Therefore, there is continuous development and increase in the popularity of solid -phase extraction (SPE) technique and its derivative techniques in the "micro" form, such as dispersive micro -solid -phase extraction (d-mu SPE), magnetic dispersive micro -solid -phase extraction (M-d-mu SPE), bar adsorption microextraction (BA mu E), rotating disk sorption extraction (RDSE), fabric phase sorption extraction (FPSE), solid phase microextraction (SPME), thin film microextraction (TFME). An important and noticeable trend in recent years has been the search for efficient sorbents based on natural compounds. This review discusses the possibilities of using natural products (cork, cotton, pollen, kapok, bamboo, sponge, algae, various seeds) and biowastes (coffee residues, bracts and peels of various fruits) as sorbents in the abovementioned solid -phase techniques. These natural materials have fibrous or porous structure, which facilitates sorption of analytes. They also have functional groups necessary for the extraction of selected analytes or may be easily modified to contain such groups. Many of 106 articles described in this review show that sorbents based on natural materials are as good as commercially available synthesized sorbents while being more friendly to the environment.