Zinc/Aluminum layered double hydroxide–titanium dioxide composite nanosheet film as novel solid phase microextraction fiber for the gas chromatographic determination of valproic acid

Magnetic Rubber@Ni-Co layered double hydroxide derived from ZIF-67 template as nanostructured sorbent; application in determination of anticancer drugs in plasma samples

In this study, a magnetic three-dimensional nano-composite based on Rubber-Fe3O4@Ni-Co Layered double hydroxide derived from ZIF-67 template was synthesized by a hydrothermal method. The proposed nano-composite was used as a sorbent for the enrichment of trace amounts of anti-cancer drugs (dasatinib and erlotinib hydrochloride) from plasma samples followed by determination using high-performance liquid chromatographic analysis (HPLC-UV). The synthesized nano-sorbent was characterized by X-ray diffraction, field emission scanning electron microscopy, Fourier transform infrared spectroscopy, vibrating-sample magnetometer, Brunauer-Emmett-Teller surface analysis, Barrett-Joyner-Halenda pore size analysis and energy dispersive X-ray spectroscopy. Under optimal experimental conditions, factors affecting on extraction efficiency such as pH, ionic strength, extraction temperature and time, desorption solvent and time, the limit of detection (LODs) and the limit of quantification (LOQs) were obtained as 0.6, 2 µg/L for both of dasatinib and erlotinib, respectively. Also, linear range of the method were 2-500 and 2-1000 µg/L for dasatinib and erlotinib, respectively. Relative standard deviations (RSD%) for the repeatability of extraction on sorbent to sorbent were obtained as 3.59, 1.97 %, and one sorbent reusability were investigated and relative standard deviation values were obtained 5.35, 3.30 % for dasatinib and erlotinib, respectively.

A novel top-down strategy for in situ construction of vertically oriented hexagonal NiCr LDHs nanosheet arrays with intercalated sulfate ions on Nichrome fiber for selective solid-phase microextraction of phenolic compounds in water samples

BACKGROUND

Phenolic compounds (PCs) are a class of polar aromatic pollutants with high toxicity in environmental water. Generally the efficient sample preparation is essential for the quantification of ultra-trace target PCs in real water sample before appropriative instrumental analysis. SPME is a convenient, solvent-free and time-saving miniaturized technique and has been recognized as a green alternative to conventional extraction techniques. In SPME, however, commercial fused-silica fibers are limited to the fragility, operation temperature, extraction capacity and selectivity as well as lifetime. Therefore, the development of new SPME fibers is always needed to overcome such limitations.

RESULTS

We presented a novel top-down strategy for in situ construction of vertically oriented hexagonal sulfate intercalated NiCr layered double hydroxide nanosheet arrays (NiCr LDHs-SO4 NSAs) on the Nichrome (NiCr) substrate by hydrothermal treatment in NaOH solution containing (NH4)2S2O8. The results showed that much shorter hydrothermal time was needed for the construction of NiCr@NiCr LDHs-SO4 NSAs fiber in the presence of (NH4)2S2O8. Moreover, the unique NiCr LDHs-SO4 NSAs coating offered open access structure, and thereby more available surface area for adsorption. The resulting fiber exhibited better extraction efficiency for phenolic compounds (PCs), faster mass transfer rate, higher mechanical stability, and longer service life than original NiCr@NiCr LDHs NSs fiber and typical commercially fused-silica fibers. After optimizing conditions, the SPME-HPLC-UV method demonstrated a linear range from 0.05 μg L-1 to 200 μg L-1 with LODs of 0.015-0.156 μg L-1 (S/N = 3) and LOQs of 0.048-0.498 μg L-1 (S/N = 10), as well as good repeatability (3.06%-5.22%) and fiber-to-fiber reproducibility (4.32%-6.49%).

SIGNIFICANCE

The developed SPME-HPLC-UV method with the constructed fiber was applied to the preconcentration and detection of different types of PCs in real water samples, showing satisfactory recoveries ranging from 86.20% to 107.8% with RSDs of 3.18%-6.69%. This study provides a new strategy for in situ construction of bimetallic hydroxides and their derived nanocomposite coatings on the NiCr fiber substrate in practical SPME application.

3D-printed solid phase microextraction fiber based on Co-Al layered double hydroxide nanosheets; application in determination of phenolic acids in fruit juice samples

3D printing technology has attracted great attention in various fields of science and technology. Application of this technology in manufacturing analytical tools is developing fast. High precision in manufacturing designed objects, fast production and low cost also green production approach by using biodegradable materials like polylactic acid is promising bright future in scientific researches. The development of new approaches in improving the functional groups of the surface of 3D printed objects in order to make 3D printed parts more functional with conventional 3D printed materials, causes the entry of many advanced materials in this field. In this study, a novel solid phase microextraction fiber was prepared based on Co-Al layered double hydroxide (LDH) nanosheets in-situ growth on 3D-printed aluminum-polylactic acid (PLA) composite and its application for determination of phenolic acids (PAs) including vanillic acid (VA), ferulic acid (FA), p-coumaric acid (p-CA), p-hydroxybenzoic acid (HBA), protocatechuic acid (PCA) and caffeic acid (CA) in fruit juice samples was investigated. The proposed fiber was prepared via a robust one-step hydrothermal synthesis of Co-Al LDH on an anodized 3D-printed Al-PLA fiber. Factors crucial for the extraction, including pH, extraction and desorption time and ionic strength were explored in detail. Under the optimal experimental conditions, for all PAs except PCA, LOD, LOQ and LDR were obtained as 0.03, 0.1 and 0.1-100.0 µgL-1, respectively. For PCA, LOD, LOQ and LDR were obtained as 0.15, 0.50 and 0.5-100.0 µgL-1, respectively.

Cold atmospheric plasma treated 3D printed polylactic acid film; application in thin film solid phase microextraction of anticancer drugs

Tyrosine Kinase Inhibitors (TKIs) represent a pharmacological category of targeted therapeutics deployed for the treatment of malignant pathologies. Considering the side effects of this class of drugs for humans, therapeutic drug monitoring (TDM) becomes important. Here, a novel and specific methodology is introduced for the quantification of two TKIs (dasatinib and erlotinib) in human plasma samples. Furthermore, this study investigates the successful application of 3D printer technology in analytical sample preparation methods. Employing a fused deposition modeling (FDM) 3D printer and polylactic acid (PLA) filament, adsorbent films were designed and produced to be utilized in thin film microextraction. The 3D printed polylactic acid film surface was modified using cold atmospheric plasma (CAP) as a fast, clean and dry surface modification method with low consumption of chemicals and energy. Subsequently, FESEM, AFM, ATR-FTIR, and WCA analysis studies were employed to effectively assess the efficacy of the plasma surface modification method for the 3D printed films. After the optimization of the plasma modification and extraction methods, human plasma samples were studied for the effectiveness of the aforementioned approach. So, the selected 3D printed films with excellent microextraction efficiency have been found to be effective in sample preparation of biological samples. The linear dynamic range (LDR), limit of detection (LOD) and limit of quantification (LOQ) were obtained 0.10-20 μgL-1, 0.03 μgL-1and 0.1 μgL-1 for dasatinib and 1.0-500 μgL-1, 0.3 μgL-1, and 1 μgL-1 for erlotinib. The results obtained indicate that the developed method proves to be successful in the effective separation of anticancer drugs.

Magnetic Rubber@ magnesium aluminum layered double hydroxide as nanostructured sorbent; application in determination of estrogenic hormones and bisphenol A

A magnetic solid-phase extraction (MSPE) method was developed for the enrichment of trace amounts of estrone (E1), 17-β-estradiol (E2) and bisphenol A (BPA) from aqueous samples using the Rubber-Fe3O4@SiO2@Mg-Al Layered double hydroxide followed by determination by HPLC. The proposed sorbent was characterized by X-ray diffraction, Field emission scanning electron microscopy, Fourier transform infrared spectroscopy, Vibrating-sample magnetometer, Thermal gravimetric analysis, N2 adsorption/desorption Brunauer-Emmett-Teller surface analysis, Barrett-Joyner-Halenda pore size analysis and Energy dispersive X-ray spectroscopy. Factors affecting the extraction efficiency such as pH, ionic strength, extraction temperature and time, desorption solvent and time were optimized. The limit of detection and quantification were obtained as 0.33, 1 µg L-1 for the E1 and E2 and BPA, respectively. Also, linear range of the method were 1-150, 1-100 and 1-150 µg L-1for E1, E2, and BPA, respectively. Relative standard deviations (RSD%) for the repeatability of extraction on one sorbent were obtained as 2.98, 1.31 and 3.50%, also, sorbent to sorbent repeatability were investigated and RSD% values were obtained as 7.58, 8.35 and 8.12% for E1, E2 and BPA, respectively.

Electrochemically synthesized NiFe layered double hydroxide modified Cu(OH)2 needle-shaped nanoarrays: A novel sorbent for thin-film solid phase microextraction of antifungal drugs

Herein, we applied a simple electrosynthesis process to deposit nickel-iron layered double hydroxides (NiFe LDH) on the surface of copper hydroxide (Cu(OH)₂) needle-shaped nanoarrays and introduce a new sorbent for thin-film solid phase microextraction (TF-SPME). For this purpose, the nanoarrays were grown via electrochemical anodization on a copper foil's surface and then modified with NiFe LDH. The synthesized sorbent was characterized by field emission-scanning electron microscopy, Brunauer-Emmett-Teller (BET), and Barrett-Joiner-Halenda (BJH) analysis, energy-dispersive X-ray spectroscopy, and X-ray diffraction. The Cu(OH)₂-NiFe LDH based TF-SPME method was used to measure antifungal drugs in veterinary plasma samples followed by HPLC-UV analysis. The effects of various parameters in the extraction efficiency, including pH (5.0), extraction time (20 min), stirring rate (500 rpm), and salt effect (5.0%), type of eluent (acetonitrile), eluent volume (100 μL) and desorption time (5 min) were thoroughly optimized. Under the optimum conditions, limits of detection for ketoconazole, clotrimazole, and miconazole were obtained below 10 ng mL^-1. Intra-day, inter-day and film-to-film RSDs% were obtained less than 6.2%, 7.3% and 7.0%, respectively. Moreover, calibration plots were linear from 30 to 5000 ng mL^-1 for ketoconazole, 8.0-1000 ng mL^-1 for clotrimazole, and 15-1000 ng mL^-1 for miconazole, with determination coefficients between 0.9937 and 0.9971. Finally, good relative recoveries (%) in the range of 85-97% were obtained for measuring trace amounts of antifungal drugs in dogs' plasma samples. As a result, the method can be considered as an appropriate alternative to the conventional sample preparation methods for measuring trace amounts of antifungal drugs in biological samples.

Recent advances in the application of layered double hydroxides in analytical chemistry: A review

In recent years, layered double hydroxides (LDHs) have garnered a lot of attention in analytical chemistry, due to their advantages such as relatively simple synthesis, low cost, possession of large specific surface area and high catalytic activity, and biocompatibility. The most common applications of LDH in analytical chemistry such as sorbents in sample extraction, electrode materials in electrochemical sensing and color indicators in colorimetric detection have been well reported. Generally, the LDHs are prepared as composites with nanomaterials, or constructed with specific three-dimensional structures, befitting the applications desired for them. However, the applications of LDHs (as extraction sorbents, color indicators and in electrochemical sensing) are usually limited in these scenarios. To help address these challenges, future trends and developmental prospects of LDHs materials in analytical chemistry are discussed in this article. Besides, the strategies associated with the design of LDHs, including the structural aspects, for potential analytical applications are presented and reviewed.

Covalent organic nanospheres: facile preparation and application in high-resolution gas chromatographic separation

A facile and rapid room-temperature solution-phase strategy was used to fabricate covalent organic nanospheres with uniform morphology and outstanding thermal/solvent stability for GC separation.

Nanostructured metal–organic frameworks, TMU-4, TMU-5, and TMU-6, as novel adsorbents for solid phase microextraction of polycyclic aromatic hydrocarbons

Zn(ii) based metal–organic frameworks were coated onto stainless steel wire and applied to the headspace solid phase microextraction of PAHs.

Ultrasound-assisted dispersive liquid–liquid microextraction followed by GC–MS/MS analysis for the determination of valproic acid in urine samples

Background: Valproic acid (VPA) is an anticonvulsant drug used for the treatment of epilepsy and bipolar disorder. A method based on simultaneous derivatization and dispersive liquid–liquid microextraction followed by GC–MS/MS analysis has been developed for the determination of VPA in urine samples. Results: This optimized and validated method shows good linearity with R2 value of 0.999. LOD and LOQ of VPA was found to be 0.4 ng ml-1 and 1.4 ng ml-1, respectively. Recovery of VPA was found to be in the range of 80 to 92%. Conclusion: The developed method can find its wide applicability for the routine analysis of VPA in toxicological and clinical laboratories.

Zinc oxide/polypyrrole nanocomposite as a novel solid phase microextraction coating for extraction of aliphatic hydrocarbons from water and soil samples

In this work, ZnO/PPy nanocomposite coating was fabricated on stainless steel and evaluated as a novel headspace solid phase microextraction (HS-SPME) fiber coating for extraction of ultra-trace amounts of environmental pollutants; namely, aliphatic hydrocarbons in water and soil samples. The ZnO/PPy nanocomposite were prepared by a two-step process including the electrochemical deposition of PPy on the surface of stainless steel in the first step, and the synthesis of ZnO nanorods by hydrothermal process in the pores of PPy matrix in the second step. Porous structure together with ZnO nanorods with the average diameter of 70 nm were observed on the surface by using scanning electron microscopy (SEM). The effective parameters on HS-SPME of hydrocarbons (i.e., extraction temperature, extraction time, desorption temperature, desorption time, salt concentration, and stirring rate) were investigated and optimized by one-variable-at-a-time method. Under optimized conditions (extraction temperature, 65±1°C; extraction time, 15 min; desorption temperature, 250°C; desorption time, 3 min; salt concentration, 10% w/v; and stirring rate, 1200 rpm), the limits of detection (LODs) were found in the range of 0.08-0.5 μg L(-1), whereas the repeatability and fiber-to-fiber reproducibility were in the range 5.4-7.6% and 8.6-10.4%, respectively. Also, the accuracies obtained for the spiked n-alkanes were in the range of 85-108%; indicating the absence of matrix effects in the proposed HS-SPME method. The results obtained in this work suggest that ZnO/PPy can be promising coating materials for future applications of SPME and related sample preparation techniques.

Recent advances in unique sample preparation techniques for bioanalysis

The extraction and/or purification of drugs and medicines from biological matrices are important objectives in investigating their toxicological and pharmaceutical properties. Many widely used methods such as liquid–liquid extraction or SPE, used for extracting, purifying and enriching drugs and medicines found in biological materials, involve laborious, intensive and expensive preparatory procedures, and they require organic solvents that are toxic to both humans and the environment. Recent trends are focused on miniaturization, high-throughput and automation techniques. All the advantages and disadvantages of these techniques and devices in biological analysis are presented, and their applications in the extraction and/or purification of drugs and medicines from biological matrices are discussed in this review.