Hexafluoroisopropanol-alkyl carboxylic acid high-density supramolecular solvent based dispersive liquid-liquid microextraction of steroid sex hormones in human urine

Recent Advances in Dispersive Liquid-Liquid Microextraction for Pharmaceutical Analysis

Sample clean-up and pre-concentration are critical components of pharmaceutical analysis. The dispersive liquid-liquid microextraction (DLLME) technique is widely recognized as the most effective approach for enhancing overall detection sensitivity. While various DLLME modes have been advanced in pharmaceutical analysis, there need to be more discussions on pre-concentration techniques specifically developed for this field. This review presents a comprehensive overview of the different DLLME modes used in pharmaceutical analysis from 2017 to May 2023. The review covers the principles of DLLME, the factors affecting microextraction, the selected applications of different DLLME modes, and their advantages and disadvantages. Additionally, it focuses on multi-extraction strategies employed for pharmaceutical analysis.

Simultaneous determination of four active compounds in Centella asiatica by supramolecular solvent-based extraction coupled with high performance liquid chromatography-tandem mass spectrometry

In the present study, a new and rapid method for determining four bioactive compounds of Centella asiatica (C. asiatica) in herbs was developed based on high performance liquid chromatography coupled with tandem mass spectrometry (HPLC-MS/MS). Supramolecular solvent (SUPRAS), formed by n-hexanol, tetrahydrofuran (THF) and water, was used for extracting madecassoside (MS), asiaticoside (AS), asiatic acid (AA) and madecassic acid (MA) from herbs. The sample was extracted with 4 mL of SUPRAS for 5 min. Then centrifugation was performed for phase separation followed by direct analysis by HPLC-MS/MS. Driving forces for the extraction of herbs in the SUPRAS involved both dispersion and hydrogen bond interactions. The effect of the parameters, including compounds of supramolecular solvents, dosage and vortex time, on the extraction efficiency was investigated. The recoveries were carried out at three levels with spiked samples and in the range of 91.6%-99.9%, with relative standard deviations between 1.7%-7.9%. The novel SUPRAS method, coupled with HPLC-MS/MS, was proved to be efficiency, green, and sensitive. It was applied for determination of four target compounds in herbs.

A review of bioanalytical applications of microextraction techniques combined with derivatization

Microextraction techniques have attracted the attention of many researchers working in the field of bioanalysis due to their unique advantages, mainly in downsizing the scale of sample preparation steps. In parallel, analytical derivatization offers a powerful combination in terms of additional sensitivity, selectivity and compatibility with modern separation techniques. The aim of this review is to discuss the most recent advances in bioanalytical sample preparation based on the combination of microextraction and analytical derivatization. Both innovative fundamental reports and analyte-targeted applications are included and discussed. Dispersive liquid-liquid extraction and solid-phase microextraction are the most common techniques that typically combined with derivatization, while the development of novel and greener protocols is receiving substantial consideration in the field of analytical chemistry.

GC-MS/MS Determination of Steroid Hormones in Urine Using Solid-Phase Derivatization as an Alternative to Conventional Methods

Solid-phase analytical derivatization (SPAD) is a promising hybrid sample preparation technique combining the clean-up and preconcentration of the sample in a single step. In this work, a novel SPAD method based on the preparation of trimethylsilyl (TMS) derivatives of steroid hormones (testosterone, estrone, DHT, estriol, estradiol, and progesterone) in Phenomenex Strata C18-E (100 mg, 1 mL) cartridges has been developed and applied for their GC-MS/MS determination in human urine samples. The proposed procedure allows the detection and quantification of steroids with limits of 1.0–2.5 and 2.5–5 ng/mL, respectively. These characteristics are comparable with those obtained with a conventional liquid–liquid extraction, while the recovery of analytes in the proposed SPAD procedure is higher. The major advantages of SPAD are a short derivatization time, high efficiency, and the possibility to automatize the procedure. However, its cost-effectiveness in routine practice is still questionable.

Determination of hormones in urine by hollow fiber microporous membrane liquid-liquid extraction associated with 96-well plate system and HPLC-FLD detection

In this work, hollow-fiber microporous membrane liquid-liquid extraction (HF-MMLLE) was associated with a 96-well plate system for the determination of estrone, 17-β-estradiol, estriol and 17-α-ethinylestradiol in urine samples. This method exhibited some advantages, such as low cost, easy application, high-throughput and environmentally-friendly aspects. The type of organic solvent to fill the membrane, ionic strength effect, sample dilution, extraction and desorption time, and desorption solvent were examined. After the optimizations, the conditions were comprised of 45 min of extraction, 1-octanol as organic solvent and 15% (w/v) of NaCl; methanol was used as desorption solvent, and the desorption time was fixed at 10 min. The dilution of the sample increased the sensitivity due to the reduction of matrix effects; thus, urine samples were diluted 40-fold. The limits of detection ranged from 0.03 μg L^-1 for 17-β-estradiol to 15 μg L^-1 for estrone, and the limits of quantification ranged from 0.1 μg L^-1 for 17-β-estradiol to 10 μg L^-1 for estrone. The intra-day precision varied from 1.0% for estriol to 13.3% for 17-α-ethinylestradiol, and inter-day precision varied from 7.3% for estrone to 18.1% for estriol. The relative recoveries varied from 82 to 118%.

Trends in hollow fibre liquid phase microextraction for the preconcentration of pharmaceutically active compounds in aqueous solution: A case for polymer inclusion membrane

Low concentrations of pharmaceutically active compounds have been reported in samples from highly complex aqueous environments. Due to their low concentrations, efficient sample pretreatment methods are needed to clean samples and concentrate the compounds of interest prior to instrumental analysis. Hollow fibre liquid-phase microextraction (HF-LPME) is an effective alternative to conventional techniques such as liquid-liquid extraction (LLE) and solid phase extraction (SPE) because it consumes less organic solvent and is less labour intensive with a short extraction time. HF-LPME involves the preconcentration and mass transfer of target analytes from an aqueous sample into an acceptor solution in the lumen of the fibre using a supported liquid membrane (SLM) impregnated in the hollow fibre pores. However, despite the high contaminant selectivity, reproducibility, and enrichment that HF-LPME offers, this technique is limited by membrane instability. Although several advances have been made to address membrane instability, they are either too costly or not feasible for industrial application. Hence, hollow fibre polymer inclusion membrane liquid-phase microextraction (HF-PIM-LPME) was introduced to ameliorate membrane instability. This new approach uses ionic liquids (ILs) as a green solvent, and has demonstrated high membrane stability, good contaminant enrichment, and similar selectivity and reproducibility to HF-SLM-LPME. Hence, this review aims to raise awareness of HF-PIM-LPME as a viable alternative for the selectivity and preconcentration of pharmaceuticals and other contaminants in aquatic environments.

Solid-phase analytical derivatization as a tool for the quantification of steroid hormones in human urine with HPLC-Q-ToF detection

A possibility of application of solid-phase analytical derivatization (SPAD) for the quantification of seven steroid hormones (testosterone, dihydrotestosterone, cortisone, cortisol, progesterone, 11α-hydroxyprogesterone, and estrone) in human urine was evaluated. To prepare urine samples for instrumental analysis, SPAD with hydroxylamine was applied after enzymatic hydrolysis of the sample. To achieve high recovery values, extraction and derivatization conditions were optimized. Cartridges packed with end-capped octadecylsilyl silica sorbent provided optimum extraction of target analytes, while the reaction with hydroxylamine in the cartridge was found as a simple and efficient way for the chemical derivatization of steroids. The obtained derivatives were detected by using reversed-phase ultra-high performance liquid chromatography-quadrupole time-of-flight mass spectrometry. The proposed procedure was validated and applied to the analysis of real urine samples to prove the applicability of the proposed method for the routine analysis.

Methacrylic functionalized hybrid carbon nanomaterial for the selective adsorption and detection of progesterone in wastewater

Progesterone, an endocrine-disrupting chemical, has been frequently detected in wastewater for decades, posing a serious threat to ecological and human health. However, it is still a challenge to achieve the effective detection of progesterone in complex matrices water samples. In this study, a novel adsorbent CNT@CS/P(MAA) was prepared by grafting methacrylic polymers on the surface of modified carbon nanomaterials. Compared with other reported materials, the hybrid carbon nanomaterial could selectively identify the progesterone in the complex industrial pharmaceutical wastewater, and its adsorption performance is almost independent of the pH and environmental temperature. In addition, this nanomaterial could be reused with a good recovery rate. The prepared nanomaterials were characterized by transmission electron microscopy, Fourier transform infrared spectroscopy, X-ray diffraction, nitrogen adsorption and desorption experiments, and thermogravimetric analysis. The results confirmed that the methacrylic polymers and chitosan layer were successfully grafted on the surface of carbon nanotubes. Adsorption isotherms, adsorption kinetics, and selectivity tests showed that CNT@CS/P(MAA) had a high adsorption capacity (44.45 mg·g-1), a fast adsorption rate and a satisfied selectivity for progesterone. Then, CNT@CS/P(MAA) was used as solid phase extraction sorbent and combined with HPLC to enrich progesterone from the wastewater samples. Under the optimum conditions, a good linearity was obtained with the correlation coefficient was 0.9998, and the limit of detection was 0.003 ng·mL-1. Therefore, this method could be used for the selective and effective detection of progesterone in industrial wastewater with complex substrates and provided a new method for the detection of progesterone in other environmental waters.

Use of green alternative solvents in dispersive liquid-liquid microextraction: A review

Dispersive liquid-liquid microextraction is one of the most widely used microextraction techniques currently in the analytical chemistry field, mainly due to its simplicity and rapidity. The operational mode of this approach has been constantly changing since its introduction, adapting to new trends and applications. Most of these changes are related to the nature of the solvent employed for the microextraction. From the classical halogenated solvents (e.g., chloroform or dichloromethane), different alternatives have been proposed in order to obtain safer and non-pollutants microextraction applications. In this sense, low-density solvents, such as alkanols, switchable hydrophobicity solvents, and ionic liquids were the first and most popular replacements for halogenated solvents, which provided similar or better results than these classical dispersive liquid-liquid microextraction solvents. However, despite the good performances obtained with low-density solvents and ionic liquids, researchers have continued investigating in order to obtain even greener solvents for dispersive liquid-liquid microextraction. For that reason, in this review, the evolution over the last five years of the three types of solvents already mentioned and two of the most promising solvent alternatives (i.e., deep eutectic solvents and supramolecular solvents), have been studied in detail with the purpose of discussing which one provides the greenest alternative.

Urinary benzophenones and synthetic progestin in Chinese adults and children: concentration, source and exposure

The endocrine-disrupting activities of UV filters and synthetic progestin have raised concerns about their adverse risks. In this study, 208 urine samples were collected from Shanghai residents for the determination of seven benzophenones (BPs) and six synthetic progestins. The highest median concentration (6.21ng g^-1 Cr) was observed in young adults (21-50 years), followed by a concentration of 3.86 ng g^-1 Cr in elderly adults (over 50 years old), and the lowest median concentration (1.32 ng g^-1 Cr) was found in children (8-11 years old). The detection rates of BP-3 and EE2 in adults were 97% and 82%, and in children were 31% and 24%, respectively. Synthetic progestin levels in Shanghai, China, were relatively low compared to other countries. And the urinary BPs level showed an increasing trend in Chinese in the past 5 years. The principal component analysis suggested that adults' exposure to BP-1 and BP-3 was related, which occurs through food or dermal absorption of these chemicals present in cosmetic products and coatings. And diet was an important exposure pathway for children exposed to BPs. Despite relatively high levels of synthetic progestin for female and obese, the total estimated daily intake (EDI) was still lower than acceptable daily intake adopted by America. In the Monte-Carlo analysis, the 95th percentile of hazard quotients (HQs) was 0.83, which indicated that potential health risks were appreciated in the studied population.

Hydrophobic magnetic nanoparticle assisted catanionic surfactant supramolecular solvent microextraction of multiresidue antibiotics in water samples

A novel extraction technique i.e. hydrophobic magnetic nanoparticle (MNP)-assisted in situ supramolecular solvent (SUPRAS) microextraction was proposed, and it was applied for the analysis of sulfonamides (SAs) and fluoroquinolones (FQs) in aqueous samples, coupled with high performance liquid chromatography-UV detection (HPLC-UV). In this extraction method, hexafluoroisopropanol-mediated salt-free catanionic surfactant based SUPRAS in situ microextraction was initially carried out; then, the SUPRAS was quickly adsorbed by the hydrophobic magnetic nanoparticles and gathered by an external magnetic field. This can greatly shorten the separation time and overcome the dependence on centrifugation, and also perform a secondary extraction of free analytes (not extracted by SUPRAS) from water samples. The magnetic separation ability of different hydrophobic MNPs was evaluated by adsorbing supramolecular aggregates from the water sample. The effective parameters affecting the extraction efficiency of the analytes were investigated and optimized using the one variable at a time method. About 3 min was required to realize the extraction of analytes with an enrichment factor (EF) of 12-53 for SAs and 79-118 for FQs. Compared with the centrifugation-assisted SUPRAS microextraction, the hydrophobic MNP-assisted SUPRAS microextraction obtained much better extraction and preconcentration efficiency. The proposed novel extraction method with HPLC-UV provided LODs of 0.21-0.76 ng mL-1 for SAs and 0.10-0.18 ng mL-1 for FQs. Good linearity was obtained with correlation coefficients ranging from 0.9962 to 0.9999. The intra- and inter-day recoveries of the target antibiotics were in the range of 92.0-111.3% with RSD% below 10.4%. The method was successfully applied to determine SAs and FQs in real water samples, such as lake water, river water, reservoir water, and wastewater.

Reversed lipid micellar hollow-fiber liquid-phase microextraction of rotigotine in rat plasma

A hollow fiber liquid phase microextraction (HF-LPME) based on a reversed lipid micelle as the extraction phase was proposed and combined with high performance liquid chromatography (HPLC) for the determination of rotigotine in biological matrix. In the proposed procedure, pieces of hollow fibers were fastened on a magnetic stir bar using a thread to provide better precision. Rotigotine was extracted from 5 mL of diluted plasma sample phase with pH 6 into reversed lipid micelle (5 mmol/L of dipalmitoyl phosphatidyl choline in n-octanol/water) impregnated in both the wall pores and the lumen of the hollow fiber. After the extraction at 900 rpm and room temperature for 30 min, the acceptor phase of reversed lipid micelle was collected for HPLC analysis. Various parameters affecting the extraction efficiency, such as type of surfactant and organic solvent, surfactant concentration, sample phase pH, salt amount, extraction time, stirring rate, and dilution factor of the plasma sample, were investigated and optimized. Furthermore, the formed reversed lipid micelle was characterized by fluorescence method. Under the optimal conditions, the linear range of rotigotine was between 2 ng/mL and 100 ng/mL with determination coefficient (r²) ≥ 0.9913. It is shown from results of method validation that the satisfactory accuracy (the relative errors between -8.5% and 3.3%), precision (the relative standard deviations from 3.8% to 8.9%), stability and matrix effect were obtained. The enrichment factor (EF) of the reversed lipid micelle-based HF-LPME for rotigotine reached 126. And the feasibility of the proposed method was confirmed by the application to the pharmacokinetic study of rotigotine in rat plasma.

Modified μ-QuEChERS coupled to diethyl carbonate-based liquid microextraction for PAHs determination in coffee, tea, and water prior to GC-MS analysis: An insight to reducing the impact of caffeine on the GC-MS measurement

A fast, sensitive and eco-friendly method was developed for the determination of fifteen polycyclic aromatic hydrocarbons (PAHs) in different environmental matrices through gas chromatography mass spectrometry (GC-MS). The method utilizes a modified and miniaturized quick easy cheap effective rugged and safe (QuEChERS) clean up procedure coupled to an air-assisted dispersive liquid-liquid microextraction (AA-DLLME) for the enrichment of the concerned compounds. The AA-DLLME uses diethyl carbonate (DEC) as a green bio-based solvent for the microextraction. DEC is considered as biodegradable (with octanol/water coefficient < 3, resulting in low potential of bioaccumulation), classified as a green solvent and considered as one of the recommended solvent alternatives based on SSG results. The AA-DLLME procedure was optimized by One-Variable-at-A-Time (OVAT) succeeded by experimental design applying Central Composite Face-centered (CCF) design. The method linear calibration was found in the range of 10-120 µg/Kg for Benzo[a]pyrene and 5-100 µg/Kg for all other PAHs with low detection limits ranging from 0.01 to 2.10 µg/Kg. It could enrich the PAHs up to 166-folds. The combination of modified μ-QuEChERS with the green AA-DLLME could sharply decrease the caffeine amount on the final extract injected to the GC-MS instrument. The method was successfully applied to coffee, tea, and water samples with acceptable % recovery (>90%). Finally, the impact of our procedure to the environment from green analytical chemistry view was assessed by a novel metric system called AGREE, proving the greenness of our procedure.

Quantification of steroid hormones in human urine by DLLME and UHPLC-HRMS detection

A procedure for the quantification of steroid hormones of various classes in human urine (androgens, estrogens, progestins, corticosteroids) has been described consisting of sample preparation by means of dispersive liquid-liquid extraction after enzymatic hydrolysis with β-glucuronidase from E. Coli followed by ultra-high performance liquid chromatography-high resolution mass spectrometry (quadrupole time-of-flight) detection. Both one-variable-at-a-time and multivariate approaches (full factorial and Box-Behnken designs) were applied to optimize sample preparation conditions. The procedure was validated using synthetic urine in the concentration range of 0.25-500 ng/mL. Then, it was applied to the analysis of real urine samples and the results were compared with those of a common liquid-liquid extraction procedure. The results obtained proved its applicability to the quantification of steroid hormones in human urine with high sensitivity and accuracy.

Restricted access supramolecular solvent based magnetic solvent bar liquid-phase microextraction for determination of non-steroidal anti-inflammatory drugs in human serum coupled with high performance liquid chromatography-tandem mass spectrometry

A hexafluroisopropanol (HFIP)-alkanol supramolecular solvent (SUPRAS) based magnetic solvent bar (MSB) liquid-phase microextraction (LPME) method was proposed for extraction of non-steroidal anti-inflammatory drugs (NSAIDs, including ketoprofen, naproxen, indomethacin and diclofenac) in human serum. The restricted access HFIP-alkanol SUPRAS was prepared by injecting a mixture of HFIP and alkanol into water. A stainless-steel needle was inserted into a piece of hollow fiber to prepare a magnetic bar. Then the magnetic bar was dipped in SUPRAS to impregnate the wall pores of the hollow fiber, followed by placing it into the serum sample for extraction. Only 4 μL of SUPRAS was consumed per bar. The MSB not only functioned for stirring, but also played the role of extraction and magnetic separation. Under the optimal extraction conditions (seven MSBs, extraction time 33 min and stirring rate 730 rpm), which was obtained by one variable-at-a-time and response surface methodology, the novel MSB-LPME was coupled with high performance liquid chromatography-tandem mass spectrometry to determine NSAIDs in human serum. The method showed a good linear relationship (correlation coefficients ≥ 0.9939). Method limits of detection and method limits of quantitation were in the range of 0.25-0.95 μg L^-1 and 0.83-3.16 μg L^-1, respectively. The recoveries for the spiked human serum samples ranged from 86.8% to 125.1% with intra- and inter-day relative standard deviations less than 9.2% and 18.1%, respectively. Moreover, the method did not require a protein precipitation step, and matrix effects of 72.8%-117.7% showed little interference with mass spectrometry detection, which was due to the double cleanup provided by the restricted access property of SUPRAS and the filtration capacity of hollow fiber. The HFIP-alkanol SUPRAS-based MSB-LPME method proved to be simple, highly efficient and environment-friendly for the pretreatment of serum/plasma.

Salting-out strategy for speciation of selenium in aqueous samples using centrifuge-less dispersive liquid-liquid microextraction

The centrifuge-less dispersive liquid-liquid microextraction (DLLME) technique was used to separate selenium species in aqueous samples. According to the salting-out effect, a simple approach was used to eliminate the centrifugation step. The optimization of the independent variables was performed using chemometric methods. Under optimal conditions, this methodology was statistically validated. The linearity was between 20 and 300 μg L^-1. The limit of detection and quantification were calculated 3.4 μg L^-1 and 10.4 μg L^-1, respectively. The values of reproducibility and repeatability were determined ≤ 9.5% and ≤ 6.4, respectively. The possibility of the method was successfully assessed by analyzing the analytes in real samples clarified satisfactory recoveries (98.1-101.4% for Se (IV) and 98.4-101.5% for Se (VI)).

Twenty years of supramolecular solvents in sample preparation for chromatography: achievements and challenges ahead

Supramolecular solvents (SUPRAS) have progressively become a suitable alternative to organic solvents for sample preparation in chromatographic analysis. The inherent properties of these nanostructured solvents (e.g. different polarity microenvironments, multiple binding sites, possibility of tailoring their properties, etc.) offer multiple opportunities for the development of innovative sample treatment platforms not approachable by conventional solvents. In this review, major achievements attained in the combination SUPRAS-chromatography in the last 20 years as well as the challenges that should be addressed in the near future are critically discussed. Among achievements, particular attention is paid to the theoretical and practical knowledge gained that has helped make substantial progress in the area. In this respect, advances in the understanding of the mechanisms involved in SUPRAS formation and SUPRAS-solute interactions driving extractions are discussed, with a view to the setting up of knowledge-based extraction procedures. Likewise, the strategies followed to improve the compatibility of SUPRAS extracts with liquid and gas chromatography and adapt SUPRAS-based extractions to different formats are presented. Ongoing efforts to apply SUPRAS in multicomponent extractions and synthesize tailored SUPRAS for the development of innovative sample treatments are highlighted. Among challenges identified, discussion is focused on the automation of SUPRAS-based sample treatment and the elucidation of SUPRAS nanostructures, which are considered essential for their acceptance in routine labs and the design of tailored SUPRAS with programmed functions. Graphical abstract.