Cloud Point Extraction Used for Separation and Preconcentration of Trace Elements in Food Samples: A Review of Recent Applications

Abstract

Food safety analysis involves many subfields. One of them is inorganic analysis aimed to the quantification of various trace elements. The main attention in this field is paid to toxic, potentially toxic, and essential trace elements. However in many cases, direct quantification of trace elements in a complex food matrix is almost impossible. To resolve this problem, a combination of a suitable separation procedure with a reliable quantification method is required to deliver accurate results. One of the separation techniques that is currently receiving considerable attention is cloud point extraction (CPE). The use of optimized CPE procedures with commonly available spectrometric methods (e.g., UV-Vis spectrophotometry, flame atomic absorption spectrometry, electrothermal atomic absorption spectrometry, hydride generation atomic absorption spectrometry, cold vapor atomic absorption spectrometry, inductively coupled plasma optical emission spectrometry) provides the powerful tool for reliable quantification of many trace elements (e.g., Al, As, Cd, Cu, Hg, Pb, Mn, Ni, Sb, Se, Sn, Zn, and many others) in various types of food matrices (e.g., fresh vegetables, ground grain samples, canned food samples, various powdered food samples, and many others), as documented by studies included in this review.

Cloud Point Extraction Combined with Electrothermal Atomic Absorption Spectrometry

“…Kvapalné potravinové vzorky zvyčajne vyžadujú menej krokov predúpravy v porovnaní s tuhými vzorkami potravín 56 . V niektorých prípadoch postačuje jednoduché nariedenie, no možno nájsť postupy, kde bola použitá evaporácia alebo destilácia 57 .…”

Cloud point method applied to the extraction and preconcentration of thiabendazole pesticide from whole grape juice samples and amperometric detection by HPLC

“…18 Unlike conventional extraction techniques, CPE can be considered environmentally friendly since it is in accordance with the principles of "Green Chemistry". [19][20][21][22][23][24] In this procedure, diluted solutions of biodegradable non-ionic surfactants are used as an extracting medium, generating very little, low toxicity, non-volatile, and highly ammable laboratory waste. [19][20][21][22][23][24] Surfactant solutions have the ability to modify some properties in order to improve the sensitivity and/or selectivity of the analytical method.…”

“…[19][20][21][22][23][24] In this procedure, diluted solutions of biodegradable non-ionic surfactants are used as an extracting medium, generating very little, low toxicity, non-volatile, and highly ammable laboratory waste. [19][20][21][22][23][24] Surfactant solutions have the ability to modify some properties in order to improve the sensitivity and/or selectivity of the analytical method. The main characteristic of surfactants is the formation of supramolecular structures that have hydrophilic and hydrophobic structural regions, which associate dynamically and spontaneously in aqueous solution from a given micellar concentration, known as critical micellar concentration (CMC).…”