Fabrication of a hierarchical dodecyl sulfate-layered double hydroxide nanocomposite on porous aluminum wire as an efficient coating for solid-phase microextraction of phenols

Progress in pre-treatment and extraction of organic and inorganic pollutants by layered double hydroxide for trace-level analysis

Continuous release of pollutants into the environment poses serious threats to environmental sustainability and human health. For trace-level analysis of pollutants, layered double hydroxide (LDH) is an attractive option to impart enhanced sorption capability and sensitivity toward pollutants because of its unique layered structure, tunable interior architecture, high anion-exchange capacities, and high porosity (e.g., Zn/Cr LDH/DABCO-IL, Ni/Al LDH, CS-Ni/Fe LDH, SDS-Fe₃O₄@SiO₂@Mg-Al LDH, Boeh/Mg/Al LDH/pC, and Fe@NiAl LDH). In concert with the well-defined analytical methodologies (e.g., HPLC and GC), the LDH materials can be employed to detect trace-level targets (e.g., as low as ∼ 20 fg/L for phenols) in aqueous environments. This review highlights LDH as a promising material for pre-treatment of a variety of organic and inorganic target pollutants in complex real matrices. Challenges and future requirements for research into LDH-based analytical methods are also discussed.

Preconcentration of digoxin using a synthetic imprinted polymer deposited upon the surface of double-layered hydroxides on porous anodised aluminium wire a triple solid-phase microextraction fibre

INTRODUCTION

A new solid-phase microextraction fibre is fabricated through polymerisation of molecularly imprinted polymer on the surface of a layered double hydroxide framework that has been fabricated via the in situ synthesis on a non-porous anodic aluminium oxide/aluminium wire as both the substrate and the aluminium source.

OBJECTIVE

The synthesized SPME fiber was performed to analyze trace digoxin in real samples.

MATERIAL AND METHOD

A one-at-a-time optimization strategy was applied for optimizing the important extraction parameters such as extraction solvent, extraction time, stirring rate, pH, ionic strength, and desorption time.

RESULT

Aluminum surface before and after anodizing and LDH structure reveal that anodizing and preparation LDH increases the surface area and adsorption capacity of aluminum wire.

CONCLUSION

Under optimum conditions, the repeatability for one fibre (n = 3), expressed as relative standard deviation (RSD %), was 5.2%.

An amino-functionalized ordered mesoporous polymer as a fiber coating for solid phase microextraction of phenols prior to GC-MS analysis

An amino-functionalized ordered mesoporous polymer (OMP-NH₂) was synthesized and applied as a fiber coating for solid phase microextraction of polar phenols from environmental samples. The fiber coating was prepared by loading the OMP-NH₂ powder onto a stainless steel wire through silicone gel. Combined with GC-MS, the fibers were employed to quantify trace of phenols in water through headspace-SPME. The characterization showed the OMP-NH₂ to have a large specific surface area (420 m² g^-1) and good thermal stability (>400 °C). Due to its mesoporous structure and favorable interactions via hydrogen bonding and π stacking interactions with phenols, the sorbent represents a promising candidate for the separation and enrichment of polar phenols. Extraction conditions, such as temperature, extraction time, salt concentration, pH value and desorption time, were fully optimized. Under the optimized conditions, the coating exhibits an enrichment effect that is ~2-10 times better than that of a commercial polyacrylate coating. Figures of merit include (a) low limits of detection (0.05-0.16 ng L^-1), (b) wide linear ranges (0.2-10,000 ng L^-1), and (c) high enrichment factors (510-2272). The relative standard deviations for one fiber and fiber-to-fiber were in the range of 4.0-6.1% and 4.6-7.4%, respectively. The method was applied to the determination of phenols in water samples and gave satisfactory recoveries between 85.4 and 112.2%. Graphical abstract An amino-functionalized ordered mesoporous polymer (OMP-NH₂) was synthesized by a solventless method and applied as headspace solid phase microextraction (HS-SPME) fiber coating for the extraction of polar phenols from the environmental samples.

Preparation of polypyrrole/nanosilica composite for solid-phase microextraction of bisphenol and phthalates migrated from containers to eye drops and injection solutions

This paper describes the electrodeposition of polyphosphate-doped polypyrrole/nanosilica nanocomposite coating on steel wire for direct solid-phase microextraction of bisphenol A and five phthalates. We optimized influencing parameters on the extraction efficiency and morphology of the nanocomposite such as deposition potential, concentration of pyrrole and polyphosphate, deposition time and the nanosilica amount. Under the optimized conditions, characterization of the nanocomposite was investigated by scanning electron microscopy and Fourier transform infra-red spectroscopy. Also, the factors related to the solid-phase microextraction method including desorption temperature and time, extraction temperature and time, ionic strength and pH were studied in detail. Subsequently, the proposed method was validated by gas chromatography-mass spectrometry by thermal desorption and acceptable figures of merit were obtained. The linearity of the calibration curves was between 0.01 and 50 ng/mL with acceptable correlation coefficients (0.9956-0.9987) and limits of detection were in the range 0.002-0.01 ng/mL. Relative standard deviations in terms of intra-day and inter-day by five replicate analyses from aqueous solutions containing 0.1 ng/mL of target analytes were in the range 3.3%-5.4% and 5%-7.1%, respectively. Fiber-to-fiber reproducibilities were measured for three different fibers prepared in the same conditions and the results were between 7.3% and 9.8%. Also, extraction recoveries at two different concentrations were ≥96%. Finally, the suitability of the proposed method was demonstrated through its application to the analysis of some eye drops and injection solutions.

Using cobalt/chromium layered double hydroxide nano-sheets as a novel packed in-tube solid phase microextraction sorbent for facile extraction of acidic pesticides from water samples

Cobalt/chromium-layered double hydroxide (Co/Cr (NO₃⁻)-LDH) nano-sheets were employed as a packed in-tube solid phase microextraction sorbent for efficient extraction of acidic pesticides from water samples.

Fast analysis of volatile compounds from Lippia citriodora with nanoporous aluminum wire as solid-phase microextraction fibres

In this study, the efficiency of nanoporous aluminium wires as fibres for headspace solid-phase microextraction (HS-SPME) of volatile compounds from Lippia citriodora was investigated and compared with two anodised methods. The prepared fibres are durable with very good chemical and thermal stability which can be coupled to GC and GC/MS. A one at-a-time optimisation strategy was applied for optimising the important extraction parameters such as extraction temperature, extraction time, sample mass and added water. Compared with hydrodistillation (HD), HS-SPME provide the advantages of a small amount of sample, time-saving, simplicity and cheapness.