Application of solid phase microextraction and needle trap device with silica composite of carbon nanotubes for determination of perchloroethylene in laboratory and field

An amide-based covalent organic framework chemically anchored on silica nanoparticles for headspace microextraction sampling of halogenated hydrocarbons in air

A needle trap device (NTD) was developed using an amide-based covalent-organic framework (COF), chemically bonded to silica nanoparticles. The NTD was coupled with gas chromatography-flame ionization detection (GC-FID) and employed for the headspace microextraction analysis of halogenated hydrocarbons (HHCs) in the air. The adsorbent was characterized using Fourier-transform infrared spectroscopy (FT-IR), X-ray diffraction analysis (XRD), transmission electron microscopy (TEM), and field-emission scanning electron microscopy (FE-SEM) techniques. Optimal values for the experimental variables were assessed using response surface methodology (RSM) with a central composite design (CCD), thereby reducing the number of experiments, material consumption, costs, and time. The optimal values for desorption time and temperature were obtained 5 min and 260 °C, respectively. Breakthrough volume (BtV) was studied over the range of 0.5 - 3 times the occupational exposure limit (OEL) and its optimal value was found to be 1200 mL. The optimal sampling temperature and relative humidity (RH) were obtained 20 °C, and 15 %, respectively. The limits of detection (LODs) and limits of quantification (LOQs) were ranged from 0.013 to 0.077 μg l-1 and 0.041 to 0.21 μg l-1, respectively, with a linear dynamic range (LDR) of 0.04 to 100 μg l-1. The method's repeatability and reproducibility (RSD %) were observed over the ranges of 5.3 - 6.4 % and 4.7 -6.9 %, respectively. A statistically validated agreement was observed between the NTD-GC-FID method and the NIOSH 1003 standard procedure for the sampling and determination of HHCs in real workplace air samples, demonstrating the reliability and accuracy of the developed approach.

Needle trap device technique: From fabrication to sampling

Needle Trap Device (NTD) as a novel, versatile, and eco-friendly technique has played an important role in analytical and environmental chemistry. The distinctive role of this interdisciplinary technique can be defended through the sampling and analysis of biological samples and industrial pollutants in gaseous and liquid environments. In recent years, significant efforts have been made to enhance the performance of the needle trap device resulting in the development of novel extraction routes by various packing materials with improved selectivity and enhanced adsorption characteristics. These achievements can lead to the facilitated pre-concentration of desired analytes. This review tries to have a comparative and comprehensive survey of the three important areas of NTD technique: I) Fabrication and preparation procedures of NTDs; II) Sampling techniques of pollutants using NTDs; and III) Employed materials as adsorbents in NTDs. In the packing-material section, the commercial and synthetic adsorbents such as carbon materials, metal-organic frameworks, aerogel, and polymers are considered. Furthermore, the limitations and potential areas for future development of the NTD technique are presented.

Polydopamine inner wall-coated hypodermic needle as microextraction device and electrospray emitter for the direct analysis of illicit drugs in oral fluid by ambient mass spectrometry

In this article, polydopamine inner wall-coated hypodermic needles (PDA-HNs) are evaluated as both microextraction devices and electrospray ionization (ESI) emitters for determining selected illicit drugs (methamphetamine, cocaine, and methadone) in oral fluid samples. The PDA film, located in the inner wall of the needle, allows the extraction of the analytes at alkaline pH, where their hydrophobic character is promoted. The extracted analytes are finally eluted in a methanol/formic acid mixture that also acts as ESI solution. For this purpose, a dedicated interface based on the connection of a PEEK tube with the needle hub is proposed. This assembly allows delivering the ESI solution by the infusion syringe pump of the mass spectrometer, providing an efficient ESI on the tip of the needle. The double use of the PDA-HNs as microextraction devices and ESI emitters permits the determination of the target analytes with limits of detection and precision (expressed as relative standard deviation) values better than 2.4 μg/L and 17.6%, respectively. The accuracy was evaluated by analyzing independent spiked oral fluid samples, obtaining good results.

Graphene-based metal and nitrogen-doped carbon composites as adsorbents for highly sensitive solid phase microextraction of polycyclic aromatic hydrocarbons

Herein, a graphene-based metal and nitrogen-doped carbon (GNC-Co) composite, derived from zeolite imidazolate framework-67 (ZIF-67)-graphene oxide composites, was successfully developed and applied as an excellent fiber coating for solid phase microextraction (SPME) with enhanced performance. The fabricated carbon has a hierarchically micro/mesoporous structure with a high specific surface area of 123 m2 g-1. The study found that pyrolytic graphene (G) has good adsorption properties for anthracene, phenanthrene, fluoranthene and pyrene, while pyrolytic ZIF-67 (NC-Co) has good adsorption properties for naphthalene, acenaphthylene, acenaphthylene and fluorene. Combined with the advantage of G and NC-Co, the synthesized composite GNC-Co enabled the integration of the unique properties of these two fascinating materials and proved to show better performance in the extraction of all polycyclic aromatic hydrocarbons (PAHs). Compared to the commercial PDMS fiber, the self-made fiber achieved GC responses about 2-9 times as high as those obtained by the commercial 30 μm PDMS fiber. Furthermore, the self-made fiber obtained low detection limits in the range of 0.01-0.74 ng L-1 and wide linearity under the optimized extraction conditions. Finally, the GNC-Co coated fiber was successfully used for the detection of PAHs in real river water samples, which proved the applicability of the method.

Analysis of formaldehyde and acrolein in the aqueous samples using a novel needle trap device containing nanoporous silica aerogel sorbent

In this research, a needle trap device (NTD) packed with nanoporous silica aerogel as a sorbent was used as a new technique for sampling and analysis of formaldehyde and acrolein compounds in aqueous and urine samples. The obtained results were compared with those of the commercial sorbent Carboxen1000. Active sampling was used and a 21-G needle was applied for extraction of gas in the sample headspace. The optimization of experimental parameters like salt addition, temperature and desorption time was done and the performance of the NTD for the extraction of the compounds was evaluated. The optimum temperature and time of desorption were 280 °C and 2 min, respectively. The ranges of limit of detection, limit of quantification and relative standard deviation (RSD) were 0.01-0.03 μg L^-1, 0.03-0.1 μg L^-1 and 2.8-7.3%, respectively. It was found that the NTD containing nanoporous silica aerogel had a better performance. Thus, this technique can be applied as an effective and reliable method for sampling and analysis of aldehyde compounds from different biological matrices like urine, exhalation and so on.

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.