Overview of Different Modes and Applications of Liquid Phase-Based Microextraction Techniques

Ion-pair vortex assisted liquid phase micro-extraction coupled with UV-visible spectrophotometry for the determination of mesalazine in pharmaceutical formulations

This study demonstrates an effective, simple, and selective method for monitoring mesalazine in pharmaceutical formulations using liquid phase micro-extraction (LPME) and spectrophotometry. Combining LPME with spectrophotometry is an efficient method for analysing various compounds in different matrices. This method is based on extracting the ion-pair formed between the blue indophenol produced by the oxidative reaction of mesalazine and syringic acid in an alkaline medium and a quaternary ammonium salt into a micro-volume of organic solvent. The experimental parameters influencing LPME performance, such as the type and concentration of the quaternary ammonium ion salt and the type and volume of the extractant solvent, were optimised for optimal detection. The linear range and the limit of detection for measuring red species in pharmaceutical formulations were determined to be 0.005-0.080 μg/mL-1 and 0.003 μg/mL-1, respectively, with a relative standard deviation of 4-6%. The method had a preconcentration factor of 50 at 520nm, making it highly efficient and reliable for monitoring mesalazine in pharmaceutical formulations.

Deep eutectic solvents for the determination of endocrine disrupting chemicals

The harmful effects of endocrine disrupting chemicals (EDCs) to humans and other organisms in the environment have been well established over the years, and more studies are ongoing to classify other chemicals that have the potential to alter or disrupt the regular function of the endocrine system. In addition to toxicological studies, analytical detection systems are progressively being improved to facilitate accurate determination of EDCs in biological, environmental and food samples. Recent microextraction methods have focused on the use of green chemicals that are safe for analytical applications, and present very low or no toxicity upon disposal. Deep eutectic solvents (DESs) have emerged as one of the viable alternatives to the conventional hazardous solvents, and their unique properties make them very useful in different applications. Notably, the use of renewable sources to prepare DESs leads to highly biodegradable products that mitigate negative ecological impacts. This review presents an overview of both organic and inorganic EDCs and their ramifications on human health. It also presents the fundamental principles of liquid phase and solid phase microextraction methods, and gives a comprehensive account of the use of DESs for the determination of EDCs in various samples.

Eco-friendly solvent bar microextraction based on a natural deep eutectic solvent and multivariate optimization for simultaneous determination of spironolactone and canrenone in urine and plasma samples

Simultaneous measurement of spironolactone and canrenone in urine and plasma provides valuable insight into renal function, and therapeutic efficacy and can be utilized to identify potential health risks and ensure patient safety throughout treatment. By adopting greener methods to analyze these compounds, significant reductions in the environmental impact of such studies can be achieved. For this purpose, a sensitive and eco-friendly solvent bar microextraction method using natural deep eutectic solvent (NDE) followed by high-performance liquid chromatography-diode array detection (HPLC-DAD) was developed to determine spironolactone and canrenone in urine and plasma samples. The extraction solvents were synthesized using NDE-based terpenoids containing menthol and camphor in various ratios. The extraction efficiency percentage (EE%) of both drugs was measured using response surface methodology (RSM) based on central composite design (CCD), and 29 extraction tests were conducted to determine the optimum conditions. Although all parameters were found to be significant, the extraction and elution times were critical for isolating the target analytes. Under optimized conditions, the linear dynamic ranges for spironolactone (SPI)/canrenone (CAN) were 11.7-104/13.1-104 μg L-1 and 21.7-104/24.6-104 μg L-1 in urine and plasma samples, respectively with R2 ≥ 0.993. The ranges of intra-/interprecision (relative standard deviation (RSD) %, n = 5) were 1.31-9.17%/ 2.4-11% with extraction recovery ≥ 88.6% for both drugs. The comparison findings with previously published methods confirmed that the developed NDE-solvent bar microextraction (SBME)-HPLC-DAD method for spironolactone and canrenone analysis displayed confident sensitivity, feasible operation, and simple analysis. Furthermore, the method's applicability and effectiveness were proven by successfully analyzing spironolactone and its metabolite canrenone in patients' urine and plasma samples.

Assessment of endocrine disruptor pollutants and their metabolites in environmental water samples using a sustainable natural deep eutectic solvent-based analytical methodology

In this work, an evaluation of the occurrence of fifteen phthalates, four metabolites and one adipate in different groundwater, seawater and wastewater samples has been carried out due to their relevance on human health as they act as endocrine disruptors. For this purpose, a sustainable, fast and easy-handling vortex-assisted liquid-liquid microextraction method using a natural hydrophobic deep eutectic solvent based on menthol and carvacrol as extraction agent, combined with ultra-high performance liquid chromatography-mass spectrometry technique, has been developed and applied for the first time. An optimization was performed to evaluate four important factors affecting the extraction performance, and an analytical validation was carried out in terms of matrix effect, linearity, extraction efficiency, and sensitivity. Recovery values were obtained in the range 72-119% for all analytes (except for monoethyl phthalate: 61.1-72.3%) with relative standard deviation values lower than 17%. Limits of quantification were found between 0.91 and 8.09 μg L-1. As a result of the assessment of 31 different environmental water samples, monoethyl phthalate, diethyl phthalate, dibutyl phthalate and bis (2-ethylhexyl) phthalate were detected and quantified at different concentrations in the range 2.59-21.17 μg L-1 in 6 samples, and diallyl phthalate, butyl benzyl phthalate, dipentyl phthalate, dicyclohexyl phthalate, dihexyl phthalate and bis (2-ethylhexyl) adipate were detected in 20 more, showing the exposition of the population to these hazardous substances.

Preconcentration and Separation of Gold Nanoparticles from Environmental Waters Using Extraction Techniques Followed by Spectrometric Quantification

The quantification of gold nanoparticles (AuNP) in environmental samples at ultratrace concentrations can be accurately performed by sophisticated and pricey analytical methods. This paper aims to challenge the analytical potential and advantages of cheaper and equally reliable alternatives that couple the well-established extraction procedures with common spectrometric methods. We discuss several combinations of techniques that are suitable for separation/preconcentration and quantification of AuNP in complex and challenging aqueous matrices, such as tap, river, lake, brook, mineral, and sea waters, as well as wastewaters. Cloud point extraction (CPE) has been successfully combined with electrothermal atomic absorption spectrometry (ETAAS), inductively coupled plasma mass spectrometry (ICP-MS), chemiluminescence (CL), and total reflection X-ray fluorescence spectrometry (TXRF). The major advantage of this approach is the ability to quantify AuNP of different sizes and coatings in a sample with a volume in the order of milliliters. Small volumes of sample (5 mL), dispersive solvent (50 µL), and extraction agent (70 µL) were reported also for surfactant-assisted dispersive liquid–liquid microextraction (SA-DLLME) coupled with electrothermal vaporization inductively coupled plasma mass spectrometry (ETV-ICP-MS). The limits of detection (LOD) achieved using different combinations of methods as well as enrichment factors (EF) varied greatly, being 0.004–200 ng L−1 and 8–250, respectively.