Application of carbon nanotubes modified with a Keggin polyoxometalate as a new sorbent for the hollow‐fiber micro‐solid‐phase extraction of trace naproxen in hair samples with fluorescence spectrophotometry using factorial experimental design

Abstract

A sensitive technique to determinate naproxen in hair samples was developed using hollow-fiber micro-solid-phase combined with fluorescence spectrophotometry. The incorporation of multi-walled carbon nanotubes modified with a Keggin polyoxometalate into a silica matrix prepared by the sol-gel method was reported. In this research, the Keggin carbon nanotubes /silica composite was used in the pores and lumen of a hollow fiber as the hollow-fiber micro-solid-phase extraction device. The device was used for the microextraction of the analyte from hair and water samples under the optimized conditions. An orthogonal array experimental design with an OA24 (4(6) ) matrix was employed to optimize the conditions. The effect of six factors influencing the extraction efficiency was investigated: pH, salt, volume of donor and desorption phase, extraction and desorption time. The effect of each factor was estimated using individual contributions as response functions in the screening process. Analysis of variance was employed for estimating the main significant factors and their contributions in the extraction. Calibration curve plot displayed linearity over a range of 0.2-10 ng/mL with detection limits of 0.072 and 0.08 ng/mL for hair and aqueous samples, respectively. The relative recoveries in the hair and aqueous matrices ranged from 103-95%. The relative standard deviation for fiber-to-fiber repeatability was 3.9%.

Proteotypic peptides of hairs for the identification of common European domestic and wild animal species revealed by in‐sample protein digestion and mass spectrometry analysis

“…Separate hair does not carry the necessary amount of information that could lead to animal species identification. However, much other additional information can be obtained by the hair analysis, for example, the content of cannabinoids [9], naproxen [10], nicotine [11], nitroanilines [12], methamphetamines [13], and prometryn [14]. For animal species identification, a follicle containing one hair or a bundle of guard hairs, or a combination of guard hairs and undercoats is used.…”

Solid‐phase microextraction of ultra‐trace amounts of tramadol from human urine by using a carbon nanotube/flower‐shaped zinc oxide hollow fiber

“…In HF‐SPME, the sol–gel‐containing synthesized nanocomposite was injected into the lumen of a small segment of polypropylene hollow fiber and the in situ gelation occurred within the fiber . This method overcomes some of the existing drawbacks on conventional SPME fibers such as their high cost, sample carryover effects, poor reusability, and fiber damages.…”

Efficient sample preparation method based on solvent-assisted dispersive solid-phase extraction for the trace detection of butachlor in urine and waste water samples

“…SPE is more flexible and efficient than LLE in terms of simplicity, low consumption of the organic solvents, flexibility in choosing the adsorbent, and high enrichment factor. Recently, SPE has been increasingly used for the preconcentration and separation of ultra‐trace amounts of inorganic and organic species from complex matrices . SPE techniques are surface‐dependent processes since their efficiency directly depends on the particle size and the surface area of the sorbent .…”