Extraction and determination of chloramphenicol in feed water, milk, and honey samples using an ionic liquid/sodium citrate aqueous two-phase system coupled with high-performance liquid chromatography

Terbium-based dual-ligand metal organic framework by diffusion method for selective and sensitive detection of danofloxacin in aqueous medium

A water-dispersible Tb(III)-based metal organic framework (TBP) was produced by diffusion technique using benzene-1,3,5-tricarboxylic acid (BTC) and pyridine as easily accessible ligands at low cost. The as-synthesized TBP with a crystalline structure and rod-shaped morphology has exhibited thermal stability up to 465 °C. Elemental analysis confirmed the presence of carbon, oxygen, nitrogen, and terbium in the synthesized MOF. TBP was used as a fluorescent probe for detection of danofloxacin (DANO) in an aqueous medium with significant enhancement of fluorescence intensity as compared to various fluoroquinolone antibiotics (levofloxacin (LEVO), ofloxacin (OFLO), norfloxacin (NOR), and ciprofloxacin (CIPRO)) with a low detection limit of 0.45 ng/mL (1.25 nm). The developed method has successfully detected DANO rapidly (i.e., response time = 1 min) with remarkable recovery (97.66-101.96%) and a relative standard deviation (RSD) of less than 2.2%. Additionally, TBP showcased good reusability up to three cycles without any significant performance decline. The in-depth mechanistic studies of the density functional theory (DFT) calculations and mode of action revealed that hydrogen bonding interactions and photo-induced electron transfer (PET) are the major factors for the turn-on enhancement behavior of TBP towards DANO. Thus, the present work provides the quick and precise identification of DANO using a new fluorescent MOF (TBP) synthesized via a unique and facile diffusion technique.

Sustainable dispersive liquid-liquid microextraction method utilizing a natural deep eutectic solvent for determination of chloramphenicol in honey: assessment of the environmental impact of the developed method

The greening of pharmaceutical analysis is gaining interest, and different approaches have been proposed, such as minimizing the consumption of hazardous reagents, replacing toxic solvents with safer alternatives, and reducing waste generation. In this work, a natural deep eutectic solvent (NADES) was synthesized and utilized as a green alternative in dispersive liquid-liquid microextraction (DLLME) for the determination of chloramphenicol in honey. Different deep eutectic solvents composed of monoterpenoids and acids were tested. The NADES system composed of menthol and acetic acid at a molar ratio of 1 : 1 was found to be the most appropriate in terms of extraction recovery. Different DLLME parameters including vortex time, centrifugation time, sample volume, and deep eutectic solvent volume were optimized. A determination coefficient of 0.9997 was achieved. Satisfactory recovery ranged from 98.8 to 101.5 with % RSD ≤4.5. The chromatographic performance of the presented method compared with other previously documented methods for determination of chloramphenicol in honey was highlighted. Additionally, the ecological impact of the developed method was assessed employing three tools: the Analytical Eco-scale, the Green Analytical Procedure Index, and the Analytical GREEnness metric. The presented method can be regarded as a green substitute for the traditional methods used for the determination of chloramphenicol in honey.

Integrated Approach to Extract and Purify Proteins from Honey by Ionic Liquid-Based Three-Phase Partitioning

The purification of value-added compounds by three-phase partitioning (TPP) is a promising alternative to conventional processes since the target compound can be easily recovered from the liquid-liquid interphase. Although this technique has been successfully applied to the recovery of proteins, the minimization of the use of salts and solvents must be pursued to improve the overall process sustainability. Accordingly, we have here investigated the use of biobased glycine-betaine ionic liquids (IL) directly with honey, a carbohydrate-rich matrix, as phase-forming components of TPP systems. These ILTPP systems were applied in the purification of major royal jelly proteins (MRJPs) from honey. The results obtained show that MRJPs mostly precipitate in the ILTPP interphase, with a recovery yield ranging between 82.8% and 97.3%. In particular, MRJP1 can be obtained with a purity level up to 90.1%. Furthermore, these systems allow the simultaneous separation of antioxidants and carbohydrates to different liquid phases. The proposed approach allows the separation of proteins, antioxidants, and carbohydrates from honey in a single step, while using only ILs and a real carbohydrate-rich matrix, thus being sustainable TPP processes.

Advances Brought by Hydrophilic Ionic Liquids in Fields Involving Pharmaceuticals

The negligible volatility and high tunable nature of ionic liquids (ILs) have been the main drivers of their investigation in a wide diversity of fields, among which is their application in areas involving pharmaceuticals. Although most literature dealing with ILs is still majorly devoted to hydrophobic ILs, evidence on the potential of hydrophilic ILs have been increasingly provided in the past decade, viz., ILs with improved therapeutic efficiency and bioavailability, ILs with the ability to increase drugs' aqueous solubility, ILs with enhanced extraction performance for pharmaceuticals when employed in biphasic systems and other techniques, and ILs displaying low eco/cyto/toxicity and beneficial biological activities. Given their relevance, it is here overviewed the applications of hydrophilic ILs in fields involving pharmaceuticals, particularly focusing on achievements and advances witnessed during the last decade. The application of hydrophilic ILs within fields involving pharmaceuticals is here critically discussed according to four categories: (i) to improve pharmaceuticals solubility, envisioning improved bioavailability; (ii) as IL-based drug delivery systems; (iii) as pretreatment techniques to improve analytical methods performance dealing with pharmaceuticals, and (iv) in the recovery and purification of pharmaceuticals using IL-based systems. Key factors in the selection of appropriate ILs are identified. Insights and perspectives to bring renewed and effective solutions involving ILs able to compete with current commercial technologies are finally provided.

Homogeneous liquid-liquid extraction as an alternative sample preparation technique for biomedical analysis

Liquid-liquid extraction is a widely used technique of sample preparation in biomedical analysis. In spite of the high pre-concentration capacities of liquid-liquid extraction, it suffers from a number of limitations including time and effort consumption, large organic solvent utilization, and poor performance in highly polar analytes. Homogeneous liquid-liquid extraction is an alternative sample preparation technique that overcomes some drawbacks of conventional liquid-liquid extraction, and allows employing greener organic solvents in sample treatment. In homogeneous liquid-liquid extraction, a homogeneous phase is formed between the aqueous sample and the water-miscible extractant, followed by chemically or physically induced phase separation. To form the homogeneous phase, aqueous samples are mixed with water-miscible organic solvents, water-immiscible solvents/cosolvents, surfactants, or smart polymers. Then, phase separation is induced chemically (adding salt, sugar, or buffer) or physically (changing temperature or pH). This mode is rapid, sustainable, and cost-effective in comparison with other sample preparation techniques. Moreover, homogeneous liquid-liquid extraction is more suitable for the extraction of delicate macromolecules such as enzymes, hormones, and proteins and it is more compatible with liquid chromatography with tandem mass spectrometry, which is a vital technique in metabolomics and proteomics. In this review, the principle, types, applications, automation, and technical aspects of homogeneous liquid-liquid extraction are discussed.

Highly Emissive Metal-Organic Frameworks for Sensitive and Selective Detection of Nitrofuran and Quinolone Antibiotics

The overuse of antibiotics makes its detection very significant for human health. New facile methods and high-performance sensory materials will be urgently needed for detection of antibiotics. Unfortunately, there are few reports on fluorescence enhancement of antibiotics detection. Herein, based on the modulability of the coordination mode, we proposed two MOFs with different coordination modes based on different metal ions: Zn-MOF (1) and Cd-MOF (2). The fluorescence of 1 and 2 can be efficiently and selectively quenched by nitrofuran antibiotics (nitrofurazone, NFZ and furazolidone, FZD) and chloramphenicol (CAP), respectively. Particularly, the matched energy levels between 2 and enrofloxacin (ENR) enables 2 with turn-on sensing for ENR. Moreover, apart from the sensitivity and selectivity, 1 and 2 also have strong recyclable ability, fast response time and anti-interference ability, which make them great potential sensory materials to detect antibiotics.

A Suitable Immunosensor for Chloramphenicol Determination: Study of Two Different Competitive Formats

Background:

deep analytical study was performed on two different formats based on a “competitive” ELISA-type assay to develop a suitable, sensitive and cheap immune device for chloramphenicol determination that could be advantageously applied to the analysis of real matrices (pharmaceutical, food and environmental).

Methods:

To this purpose peroxidase enzyme as a marker and an amperometric electrode for hydrogen peroxide, as a transducer, were used. Through the first competitive format, chloramphenicol determination was based on the competition between chloramphenicol and conjugated with biotin-avidinperoxidase chloramphenicol, both free in solution, for anti-chloramphenicol immobilized in the membrane, while the second competitive format was based on the competition between free in solution chloramphenicol and immobilized in membrane one, for anti-chloramphenicol biotin-avidin-peroxidase conjugated free in solution.

Results:

The immunosensor was optimized by comparing the two used different “competitive” working formats on the basis of respective Kaff values, that were found to be about 105 and 104 (mol L-1)-1. The developed immune device displayed good selectivity for Chloramphenicol and LOD (limit of detection) was of the order of 10-9 mol L-1. The immunosensor was also used to test the presence of Chloramphenicol in real matrices such as cow milk, river wastewater and pharmaceutical formulations; recovery tests, using the standard addition method, gave satisfactory results.

Conclusion:

The results proved the validity of this immune device based on the competition between chloramphenicol and conjugated chloramphenicol obtained using biotin-avidin-peroxidase format, by which it is possible to carry out the analysis of chloramphenicol in milk and in river waste-waters with a % RSD ≤ 5 and with recovery values between 96% and 103%.

Magnetic nanoparticles assisted dispersive liquid-liquid microextraction of chloramphenicol in water samples

This work describes the development of a new methodology based on magnetic nanoparticles assisted dispersive liquid-liquid microextraction (DLLME-MNPs) for preconcentration and extraction of chloramphenicol (CAP) antibiotic residues in water. The approach is based on the use of decanoic acid as the extraction solvent followed by the application of MNPs to magnetically retrieve the extraction solvent containing the extracted CAP. The coated MNPs were then desorbed with methanol, and the clean extract was analysed using ultraviolet-visible spectrophotometry. Several important parameters, such as the amount of decanoic acid, extraction time, stirring rate, amount of MNPs, type of desorption solvent, salt addition and sample pH, were evaluated and optimized. Optimum parameters were as follows: amount of decanoic acid: 200 mg; extraction time: 10 min; stirring rate: 800 rpm; amount of MNPs: 60 mg; desorption solvent: methanol; salt: 10%; and sample pH, 8. Under the optimum conditions, the method demonstrated acceptable linearity (R ² = 0.9933) over a concentration range of 50-1000 µg l^-1. Limit of detection and limit of quantification were 16.5 and 50.0 µg l^-1, respectively. Good analyte recovery (91-92.7%) and acceptable precision with good relative standard deviations (0.45-6.29%, n = 3) were obtained. The method was successfully applied to tap water and lake water samples. The proposed method is rapid, simple, reliable and environmentally friendly for the detection of CAP.

Ionic Liquid Aqueous Two-Phase Systems From a Pharmaceutical Perspective

Aqueous Two-Phase Systems (ATPSs) have been extensively studied for their ability to simultaneously separate and purify active pharmaceutical ingredients (APIs) and key intermediates with high yields and high purity. Depending on the ATPS composition, it can be adapted for the separation and purification of cells, nucleic acids, proteins, antibodies, and small molecules. This method has been shown to be scalable, allowing it to be used in the milliliter scale for early drug development to thousands of liters in manufacture for commercial supply. The benefits of ATPS in pharmaceutical separations is increasingly being recognized and investigated by larger pharmaceutical companies. ATPSs use identical instrumentation and similar methodology, therefore a change from traditional methods has a theoretical low barrier of adoption. The cost of typical components used to form an ATPS at large scale, particularly that of polymer-polymer systems, is the primary challenge to widespread use across industry. However, there are a few polymer-salt examples where the increase in yield at commercial scale justifies the cost of using ATPSs for macromolecule purification. More recently, Ionic Liquids (ILs) have been used for ATPS separations that is more sustainable as a solvent, and more economical than polymers often used in ATPSs for small molecule applications. Such IL-ATPSs still retain much of the attractive characteristics such as customizable chemical and physical properties, stability, safety, and most importantly, can provide higher yield separations of organic compounds, and efficient solvent recycling to lower financial and environmental costs of large scale manufacturing.

The role of ionic liquid [C4 C1 im]Br as an adjuvant on the two-phase formation and the extraction of l-phenylalanine in ABS composed of PEG400 and potassium citrate at different temperatures

The potential of {polyethylene glycol 400 + potassium citrate} aqueous biphasic system (ABS) with ionic liquid (IL) 1-butyl-3-methylimidazolium bromide ([C₄ C₁ im]Br) as an adjuvant is examined for the extraction of l-phenylalanine (Phe), as a model biomolecule, at different temperatures and system compositions. The binodal curves and liquid-liquid equilibrium data were determined by the addition of 5 wt% IL to investigate its effect on phase diagrams and Phe partition coefficients. The results indicate that binodal curves of systems with and without IL are more deviated from each other with decreasing temperature. Moreover, IL has a high tendency to partition into the PEG-rich phase. This tendency increases with increasing temperature and system compositions. For Phe, the partition coefficients obtained in this work (K_Phe ≈ 5.5-81.2) are significantly higher than those observed in other conventional PEG-inorganic salt ABS (K_Phe ≈ 0.5-2.5), water-immiscible ILs two-phase extraction systems (K_Phe ≈ 0.02-1.2), or even, in the IL-based ABS with the same IL as the main phase-forming component (K_Phe ≈ 3.2). The phase hydrophobicity, salting-out and π⋯π stacking seem to be the main driving forces to affect the extraction aptitude of the studied ABS for Phe. Furthermore, the performance of using [C₄ C₁ im]Br as adjuvant to improve the partition of Phe in the studied ABS at different temperatures seems to be ruled by the differences in the phases hydrophobicities. Finally, the experimental tie lines and partition coefficients are accurately correlated using the NRTL model. © 2018 American Institute of Chemical Engineers Biotechnol. Prog., 2018 © 2018 American Institute of Chemical Engineers Biotechnol. Prog., 34:1149-1166, 2018.

Analysis of acetylcholinesterase inhibitors by extraction in choline saccharinate aqueous biphasic systems

Ionic liquid-based aqueous biphasic systems (IL-ABS) formed by ILs composed of ions of low toxicity, choline ([Chol]⁺) coupled with saccharinate ([Sac]^-) and acesulfamate ([Ace]^-), and inorganic salts with distinct water-structuring properties were employed for simultaneous extraction and concentration of acetylcholinesterase (AChE) inhibitors - galantamine (gal), N-desmethyl galantamine (des) and ungiminorine (ung). Comprehensive experiments aimed to assess the influence of salt and IL type and concentration, as well as the pH and temperature on the phase-forming ability and distribution of the target alkaloids between the two phases formed reveled that the IL anion and pH are the most important factors. At the optimal conditions found a quantitative recovery into the IL-rich phase of gal, des and ung was achieved in a single extractive step. These results were further used as a platform for the development of a simple and safer sample pretreatment method for analysis of the three analytes, followed by RP-HPLC/UV detection. The method showed satisfactory analytical performance, the latter allowing quantitative determination of these AChE inhibitors in pharmaceutical dosage form and in human urine.

Ionic-Liquid-Mediated Extraction and Separation Processes for Bioactive Compounds: Past, Present, and Future Trends

Ionic liquids (ILs) have been proposed as promising media for the extraction and separation of bioactive compounds from the most diverse origins. This critical review offers a compilation on the main results achieved by the use of ionic-liquid-based processes in the extraction and separation/purification of a large range of bioactive compounds (including small organic extractable compounds from biomass, lipids, and other hydrophobic compounds, proteins, amino acids, nucleic acids, and pharmaceuticals). ILs have been studied as solvents, cosolvents, cosurfactants, electrolytes, and adjuvants, as well as used in the creation of IL-supported materials for separation purposes. The IL-based processes hitherto reported, such as IL-based solid-liquid extractions, IL-based liquid-liquid extractions, IL-modified materials, and IL-based crystallization approaches, are here reviewed and compared in terms of extraction and separation performance. The key accomplishments and future challenges to the field are discussed, with particular emphasis on the major lacunas found within the IL community dedicated to separation processes and by suggesting some steps to overcome the current limitations.

Removal of Non-Steroidal Anti-Inflammatory Drugs from Aqueous Environments with Reusable Ionic-Liquid-based Systems

In the current era of human life, we have been facing an increased consumption of Non-Steroidal Anti-Inflammatory Drugs (NSAIDs). Nevertheless, NSAIDs are not completely metabolized by humans and are further excreted into domestical effluents. Several studies have been showing that a wide variety of pharmaceuticals are present in water effluents and are thus a matter of serious concern in the public health. Although treatment plants use sophisticated technologies for pollutants/contaminants removal, none of these processes was particularly designed for NSAIDs. In this perspective, this work addresses the use of a liquid-liquid extraction approach, employing ionic liquids (ILs), for the removal of NSAIDs from aqueous media. In particular, aqueous biphasic systems (ABS) composed of ILs and aluminium-based salts, which are already used in water treatment plants, were tested for the removal of diclofenac, ibuprofen, naproxen and ketoprofen. With these systems, extraction efficiencies of NSAIDs up to 100% were obtained in a single-step. The recovery of NSAIDs from the IL medium and the recyclability of the IL-rich phase were then ascertained to guarantee the development of a more sustainable and cost-effective strategy. Based on the remarkable increase in the solubility of NSAIDs in the IL-rich phase (from a 300- to a 4100-fold when compared with pure water), water was then studied as an effective anti-solvent, and where single-step recovery percentages of NSAIDs from the IL-rich phase up to 91% were obtained. After the "cleaning" of the IL-rich phase by the induced precipitation of NSAIDs, the phase-forming components were recovered and reused in four consecutive cycles, with no detected losses on both the extraction efficiency and recovery of NSAIDs by induced precipitation. Finally, an integrated process is here proposed, which comprises the (i) removal of NSAIDs from aqueous media, (ii) the cleaning of the IL-rich phase by the recovery of NSAIDs by induced precipitation, and (iii) the phase-forming components recycling and reuse, aiming at unlocking new doors for alternative treatment strategies of aqueous environments.

Feasibility of a novel multispot nanoarray for antibiotic screening in honey

Practical solutions for multiple antibiotic determination in food are required by the food industry and regulators for cost-effective screening purposes. This study describes the feasibility in development and preliminary performance of a novel multispot nanoarray for antibiotic screening in honey. Using a multiplex approach, the metabolites of the four main nitrofuran antibiotics, including morpholinomethyl-2-oxazolidone (AMOZ), 3-amino-2-oxazolidinone (AOZ), semicarbazide (SEM), 1-aminohydantoin (AHD) and chloramphenicol (CAP), were simultaneously detected. Antibodies specific to the five antibiotics were nano-spotted onto microtitre plate wells and a direct competitive assay format was employed. The assay characteristics and performance were evaluated for feasibility as a screening tool for antibiotic determination in honey to replace traditional ELISAs. Optimisation of the spotting and assay parameters was undertaken with both individual and multiplex calibration curves generated in PBS and a honey matrix. The limits of detection as determined by the 20% inhibitory concentrations (IC₂₀) were determined as 0.19, 0.83, 0.09, 15.2 and 35.9 ng ml^-1 in PBS, 0.34, 0.87, 0.17, 42.1 and 90.7 ng ml^-1 in honey (fortified at the start of the extraction), and 0.23, 0.98, 0.24, 24.8 and 58.9 ng ml^-1 in honey (fortified at the end of the extraction) for AMOZ, AOZ, CAP, SEM and AHD respectively. This work has demonstrated the potential of multiplex analysis for antibiotics with results available for 40 samples within a 90-min period for antibiotics sharing a common sample preparation. Although both the SEM and AHD assay do not show the required sensitivity with the antibodies available for use to meet regulatory limits, with further improvements in these particular antibodies this multiplex format has the potential to show a reduction in cost with reduced labour time in combination with the high-throughput screening of samples. This is the first 96-well spotted microtitre plate nanoarray for the semi-quantitative and simultaneous analysis of antibiotics.

Aqueous two-phase system (ATPS): an overview and advances in its applications

Aqueous two-phase system (ATPS) is a liquid-liquid fractionation technique and has gained an interest because of great potential for the extraction, separation, purification and enrichment of proteins, membranes, viruses, enzymes, nucleic acids and other biomolecules both in industry and academia. Although, the partition behavior involved in the method is complex and difficult to predict. Current research shows that it has also been successfully used in the detection of veterinary drug residues in food, separation of precious metals, sewage treatment and a variety of other purposes. The ATPS is able to give high recovery yield and is easily to scale up. It is also very economic and environment friendly method. The aim of this review is to overview the basics of ATPS, optimization and its applications.

Improved extraction of fluoroquinolones with recyclable ionic-liquid-based aqueous biphasic systems

In the past few years, the improvement of advanced analytical tools allowed to confirm the presence of trace amounts of metabolized and unchanged active pharmaceutical ingredients (APIs) in wastewater treatment plants (WWTPs) as well as in freshwater surfaces. It is known that the continuous contact with APIs, even at very low concentrations (ng L^-1-μg L^-1), leads to serious human health problems. In this context, this work shows the feasibility of using ionic-liquid-based aqueous biphasic systems (IL-based ABS) in the extraction of quinolones present in aqueous media. In particular, ABS composed of imidazolium- and phosphonium-based ILs and aluminium-based salts (already used in water treatment plants) were evaluated in one-step extractions of six fluoroquinolones (FQs), namely ciprofloxacin, enrofloxacin, moxifloxacin, norfloxacin, ofloxacin and sarafloxacin, and extraction efficiencies up to 98% were obtained. Despite the large interest devoted to IL-based ABS as extractive systems of outstanding performance, their recyclability/reusability has seldomly been studied. An efficient extraction/cleaning process of the IL-rich phase is here proposed by FQs induced precipitation. The recycling of the IL and its further reuse without losses in the ABS extractive performance for FQs were established, as confirmed by the four consecutive removal/extraction cycles evaluated. This novel recycling strategy supports IL-based ABS as sustainable and cost-efficient extraction platforms.

Aqueous biphasic systems composed of ionic liquids and acetate-based salts: phase diagrams, densities and viscosities

Ionic-liquid-based aqueous biphasic systems (IL-based ABS) have been largely investigated as promising extraction and purification routes. In this context, the determination of their phase diagrams and the physical properties of the coexisting phases are of high relevance when envisaging their large-scale applications. Low viscosities improve the mass transfer and reduce energy consumptions, while the knowledge on their densities is important for the equipment design. In this work, novel phase diagrams for aqueous solutions of imidazolium-based ILs combined with acetate-based salts, namely KCH3CO2 or NaCH3CO2, are reported and discussed. The ability of the acetate-based salts to induce the phase separation not only depends on the ions hydration energy, but also on the concentration of "free" ions in solution. The tie-lines, tie-line lengths and critical points are also addressed. Experimental measurements of density and viscosity of the coexisting phases, for the different systems and at several compositions and temperatures, are additionally presented. The Othmer-Tobias and Bancroft equations are also applied to ascertain on the tie-lines coherence. It is here shown that low-viscous IL-based ABS, with a high difference in the densities of the coexisting phases, can be formed with organic and biodegradable salts thus offering enhanced features over conventional polymer-based systems.

Selective isolation of hemoglobin by use of imidazolium-modified polystyrene as extractant

Ionic liquids have attracted much attention in the analysis of a variety of species. The functional groups in ionic liquids can result in highly efficient separation and enrichment and, because of their typical lack of volatility, they are environmentally benign. We grafted imidazole cations onto the surface of chloromethyl polystyrene, denoted PS-CH2-[MIM](+)Cl(-), and this modified polymer was used to selectively extract the protein hemoglobin (Hb). The prepared extractant PS-CH2-[MIM](+)Cl(-), containing 2 mmol immobilized imidazole groups per gram polymer, was characterized by FT-IR, surface charge analysis, and elemental analysis. The adsorption efficiency was 91%. The adsorption capacity of the PS-CH2-[MIM](+)Cl(-) for Hb was 23.6 μg mg(-1), and 80% of the retained Hb could be readily recovered by use of 0.5% (m/v) aqueous sodium dodecyl sulfate (SDS) solution as eluate. The activity of the eluted Hb was approximately 90%. The prepared imidazole-containing solid phase polymer was used for direct adsorption of Hb without use of any other solid matrix as support of the ionic liquid. The material was used in practice to isolate Hb from human whole blood.