Application of ComplexGAPI for the green assessment of a deep eutectic solvent-based ferrofluid assisted liquid-liquid microextraction method for detection of dimethyl phthalate in beverage samples

Influence of co-solvents on properties of terpene-based eutectic mixtures: Implications for skin delivery

Terpene-based eutectic mixtures (EMs) are attractive platforms for transdermal delivery due to their solubilizing potential and ability to alter the barrier function of the stratum corneum (SC). Despite this, little is known about the effect of diluting EMs with co-solvents (CSs) on their solubility- and permeation-enhancing properties. Furthermore, insufficient attention has been paid to comparing these platforms with traditional solvents, such as propylene glycol (PG) or ethanol (EtOH). To address this gap, the present study investigates the impact of the CS content in EM:CS blends on the transdermal delivery of clotrimazole (CLOT). Two CSs, PG and EtOH, and two terpene-based EMs, menthol:thymol and thymol:β-citronellol, were used. Each of the EMs was investigated at two different molar ratios between the terpenes, with one being their eutectic point, to explore its potential benefit for skin permeation. At each step, properties of the blends were compared with those of pure CSs. The EM:CS blends showed a better solubilizing potential for CLOT than EMs or CSs on their own. A higher content of CSs in the blends resulted in a higher skin permeation and retention of CLOT, and a lower degree of disarrangement of the SC structure. Furthermore, the blends of EMs at their EPs led to overall poorer permeation profiles, implying that the permeation rate is more affected by the properties of the individual terpenes than by the specific ratio at the eutectic point between them. In conclusion, addition of CSs to the EMs promotes permeation and retention of CLOT, while reducing the skin impairment caused by the terpenes.

Deep eutectic solvents with solid supports used in microextraction processes applied for endocrine-disrupting chemicals

The determination of endocrine-disrupting chemicals (EDCs) has become one of the biggest challenges in Analytical Chemistry. Due to the low concentration of these compounds in different kinds of samples, it becomes necessary to employ efficient sample preparation methods and sensitive measurement techniques to achieve low limits of detection. This issue becomes even more struggling when the principles of the Green Analytical Chemistry are added to the equation, since finding an efficient sample preparation method with low damaging properties for health and environment may become laborious. Recently, deep eutectic solvents (DESs) have been proposed as the most promising green kind of solvents, but also with excellent analytical properties due to the possibility of custom preparation with different components to modify their polarity, viscosity or aromaticity among others. However, conventional extraction techniques using DESs as extraction solvents may not be enough to overcome challenges in analysing trace levels of EDCs. In this sense, combination of DESs with solid supports could be seen as a potential solution to this issue allowing, in different ways, to determine lower concentrations of EDCs. In that aim, the main purpose of this review is the study of the different strategies with solid supports used along with DESs to perform the determination of EDCs, comparing their advantages and drawbacks against conventional DES-based extraction methods.

Extraction and determination of aflatoxin B1 in cereal samples using pH-switchable hydrophobic deep eutectic solvents followed by HPLC-FL analysis

A quick, simple and environmentally friendly liquid phase microextraction (LPME) sample pretreatment procedure was proposed based on pH-switchable hydrophobic deep eutectic solvents (HDESs) and high performance liquid chromatography coupled with a fluorescence detector (HPLC-FL). This method was used for the quantitative study of aflatoxin B1 (AFB1) and applied to eight widely consumed cereal samples. In this method, six different DESs were synthesized and then their pH-switchability was investigated. DESs that could be switched with pH were employed for separation and preconcentration of AFB1 in cereal samples. In this method, dispersing the extractant phase in the aqueous solution and subsequent phase separation are performed only by changing the pH. Important parameters affecting extraction, such as the type of DES and its volume, concentration of KOH, volume of HCL, effect of salt and extraction time were investigated and optimum conditions were obtained. Under the optimum conditions, relative standard deviation (RSD) values for intra-day and inter-day of the method based on seven replicate measurements of 5.0 μg kg-1 of AFB1 in cereal samples were 3.3 and 5.2%, respectively. The calibration graphs were linear in the range of 0.007-20 μg kg-1 and limit of detection (LOD) was 0.002 μg kg-1. The relative recoveries of real cereal samples which have been spiked with different levels of AFB1 were 90.8-107.5%.