Headspace solid phase microextraction of nicotine using thin layer chromatography plates modified with carbon dots

A Review on the Applications of Quantum Dots in Sample Preparation

In recent years, despite significant advances in preconcentration and preparation techniques that have led to efficient recovery and accurate measurement of target compounds. There is still a need to develop adsorbents with unique and efficient features such as high pore volume and surface area, reactivity, easy synthesis, low toxicity, and compatibility with the environment, which increase the adsorption capacity and increase extraction efficiency. Semiconductor nanocrystals called quantum dots (QDs) with a size of less than 10 nm are three-dimensional nanoparticles with a spherical, rod, or disc structure that have significant potential in extraction as adsorbents due to their excellent properties such as low toxicity, reactivity, environmental friendliness, and hydrophilic and hydrophobic interactions. One of the most basic issues in the development of adsorbents is to increase the effective surface and, as a result, their extraction efficiency. QDs, having an effective surface much higher than conventional nanomaterials, are a suitable option for extracting target compounds in different environments. This work comprehensively reviews QD-based extraction methods and surface modification strategies of QDs based on functional groups, ligands, and materials from 2013 to 2024. In addition, the applications of QD-based composites for the extraction of organic and inorganic analytes (residues of drugs in human blood and plasma, toxins, pesticides, pollutants from chemical industries, heavy metals, etc.) in different matrices are investigated.

A low-cost eco-friendly fast drug extraction (FaDEx) technique for environmental and bio-monitoring of psychoactive drug in urban water and sports-persons' urine samples

Nicotine is the most prominent psychoactive/addictive chemical substance consumed worldwide among young players in team sports. Moreover, urinary nicotine discharge and nicotine-based products disposal in environmental waters has been unavoidable in recent years. Therefore, sensitive monitoring of nicotine content in environmental waters and human urine samples is essential. In this study, we developed a miniaturized novel green, low-cost, sensitive, in-syringe-based semi-automated fast drug extraction (FaDEx) protocol coupled with gas chromatography-flame ionization detection (GC-FID) for the efficient environmental and bio-monitoring of nicotine in aqueous samples. The FaDEx method consists of two steps; firstly, the target analyte was extracted using dimethyl carbonate (a green solvent) and extraction salts. After that, the extraction solvent was passed automatically through the solid-phase extraction cartridge at a constant flow rate for the cleanup process to achieve the sensitive nicotine analysis by GC-FID. Under optimized experimental conditions, the developed method showed excellent linearity over the concentration ranges between 20-2000 ng mL^-1 with a correlation coefficient >0.99. The detection and quantification limits were 4 and 20 ng mL^-1, respectively. The presented method was applied to monitor and assess nicotine exposure in sports-persons' urine and environmental water samples. The method accuracy and precision in terms of relative recovery and relative standard deviation (for triplicate analysis) were 85.4-110.2% and ≤8%, respectively. Finally, the impact of our procedure on the environment from a green analytical chemistry view was assessed using a novel metric system called AGREE, and obtained the greenness score of 0.87, indicating its an efficient alternative green analytical protocol for routine environmental and bio-monitoring of nicotine in environmental and biological samples.

Nicotine in Complex Samples: Recent Updates on the Pretreatment and Analysis Method

Nicotine is a significant evaluation index of tobacco and its related products' quality, but nicotine overdose can pose serious health hazards and cause addiction and dependence, thus it can be seen that it is necessary to find suitable and efficient detection methods to precisely detect nicotine in diverse samples and complex matrices. In this review, an updated summary of the latest trends in pretreatment and analytical techniques for nicotine is provided. We reviewed various sample pretreatment methods, such as solid phase extraction, solid phase microextraction, liquid phase microextraction, QuEChERS, etc., and diverse nicotine assay methods including liquid chromatography, gas chromatography, electrochemical sensors, etc., focusing on the developments since 2015. Furthermore, the recent progress in the applications and applicability of these techniques as well as our prospects for future developments are discussed.HighlightsUpdated pretreatment and analysis methods of nicotine were systematically summarized.Microextraction and automation were main development trends of nicotine pretreatment.The introduction of novel materials added luster to nicotine pretreatment.The evolutions of ion source and mass analyzer were emphasized.

Simultaneous enrichment and analysis of tobacco alkaloids by microextraction coupled with mass spectrometry using a poly (N-isopropyl-acrylamide-co-divinyl-benzene-co-N, N'-methylene diacrylamide) monolithic column

Herein, we realized the simultaneous online detection of six tobacco alkaloids (TAs) by in-tube solid-phase microextraction (In-tube SPME) coupled with mass spectrometry by a rapid, sensitive, and matrix effect-free method requiring no chromatographic separation and only minimal sample pre-treatment. A poly (N-isopropylacrylamide-co-divinylbenzene-co-N, N'-methylenediacrylamide) [Poly (NIPAAm-co-DVB-co-MBAA)] monolithic column was designed according to the chemical structures of selected TAs and used as an extraction medium engaging in hydrophobic, π-π, and hydrogen bonding interactions with analytes, allowing them to be effectively extracted. A number of important parameters were systematically optimized to achieve maximal extraction efficiency. The ion intensity of the TAs signals obtained by in-tube SPME-MS were higher than the direct MS mode by about 400 folds with the signal-to-noise ratio improved by 2-7 folds. The detection limits of the six TAs were determined as 1.99-4.06 ng g^-1, with good linearity with correlation coefficients exceeding 0.99 obtained under optimal extraction conditions. Besides, TA recoveries in cigarette tobacco spiked at three concentration levels were in the range of 76.4-100.2%, and the corresponding RSDs (n = 5) were obtained as 4.32-7.16%. The extraction performance of the poly (NIPAAm-co-DVB-co-MBAA) monolithic column was well reproducible, with intra- or inter-day precision RSDs determined not to exceed 7.38%. Finally, no marked matrix effects were observed when the developed method was applied to the analysis of both high-abundance and trace-level TAs in practical samples, and the above technique was therefore concluded to be well suited for the detection of TAs in cigarette tobacco or other products.

Fabrication of a magnetic metal–organic framework molecularly imprinted polymer for extraction of anti-malaria agent hydroxychloroquine

A new magnetic metal–organic framework molecularly imprinted polymer was synthesized by the sol–gel method for the determination of hydroxychloroquine sulfate.

Monolithic Solid Based on Single-Walled Carbon Nanohorns: Preparation, Characterization, and Practical Evaluation as a Sorbent

A monolithic solid based solely on single walled carbon nanohorns (SWNHs) was prepared without the need of radical initiators or gelators. The procedure involves the preparation of a wet jelly-like system of pristine SWNHs followed by slow drying (48 h) at 25 °C. As a result, a robust and stable porous network was formed due to the interaction between SWNHs not only via π-π and van der Waals interactions, but also via the formation of carbon bonds similar to those observed within dahlia aggregates. Pristine SWNHs and the SWNH monolith were characterized by several techniques, including scanning electron microscopy (SEM), transmission electron microscopy (TEM), confocal laser scanning microscopy, Raman spectroscopy, X-ray photoelectron spectroscopy (XPS), and nitrogen intrusion porosimetry. Taking into account the efficiency of carbon nanoparticles in sorption processes, the potential applicability of the SWNH-monolith in this research field was explored using toluene; m-, p-, and o-xylene; ethylbenzene; and styrene, as target analytes. Detection limits were 0.01 µg·L⁻¹ in all cases and the inter-day precision was in the interval 7.4–15.7%. The sorbent performance of the nanostructured monolithic solid was evaluated by extracting the selected compounds from different water samples with recovery values between 81.5% and 116.4%.

Comparison of the Conventional and Electroenhanced Direct-Immersion Solid-Phase Microextraction for Sampling of Nicotine in Biological Fluids of the Human Body

A stainless steel fiber was made porous and adhesive by platinization and then coated by nanostructured polypyrrole (PPy), using an appropriate electrophoretic deposition (EPD) method. The morphological surface structure and functional groups of the PPy-coated fiber were studied using SEM (Scanning electron microscope) instrument. The prepared fiber was used for comparison of direct immersion (DI) and electroenhanced direct immersion solid-phase microextraction (EE-DI-SPME) of nicotine in human plasma and urine samples followed by gas chromatography flame ionization detector (GC-FID) determination. The effects of the influential experimental parameters on the efficiency of the DI-SPME and EE-DI-SPME methods, including the pH and ionic strength of the sample solution, applied Direct current (DC) voltage, extraction temperature and time and stirring rate, were optimized. Under the optimal conditions, the calibration curves for the DI-SPME-GC-FID and EE-DI-SPME-GC-FID methods were linear over the ranges of 0.1⁻10.0 μg mL^-1 and 0.001⁻10.0 μg mL^-1, respectively. The relative standard deviations (RSDs, n = 6) were found to be 6.1% and 4.6% for the DI and EE strategies, respectively. The LODs (limit of detection) of the DI-SPME-GC-FID and EE-DI-SPME-GC-FID methods were found to be 10 and 0.3 ng mL^-1, respectively. The relative recovery values (for the analysis of 1 µg mL^-1 nicotine) were found to be 91⁻110% for EE-DI-SPME and 75⁻105% for DI-SPME. The enrichment factors for DI-SPME and EE-DI-SPME sampling were obtained as 38,734 and 50,597, respectively. The results indicated that EE-SPME was more efficient for quantitation of nicotine in biological fluids. The developed procedure was successfully carried out for the extraction and measurement of nicotine in real plasma and urine samples.

Carbon dots as absorbance promoter probes for detection of Cu(ii) ions in aqueous solution: central composite design approach

In this work, the use of carbon dots (CDs) as a complexing agent and sensitizer in a polymeric matrix for determination of copper(ii) by UV-vis spectroscopy is reported for the first time.

Design of novel and modified dual optode membrane based on carbon dots for both ultratrace copper(ii) and cobalt(ii): derivative spectrophotometric and central composite design study

A selective, accurate and highly sensitive optical chemical sensor (optode) for the simultaneous determination of copper(ii) and cobalt(ii) without any prior separation or purification ion sensing was developed.

Design and construction of a new optical solid-state mercury(ii) sensor based on PVC membrane sensitized with colloidal carbon dots

A new Hg²⁺ ion solid-state double layer sensor impregnated with colloidal carbon dots and N′-(3-(4-(dimethylamino)phenyl)allylidene)isonicotinohydrazide (NDPAI, as a second layer) was inserted in plasticized polyvinyl chloride (PVC) as the first layer.

Dispersion of hydrophobic magnetic nanoparticles using ultarsonic-assisted in combination with coacervative microextraction for the simultaneous preconcentration and determination of tricyclic antidepressant drugs in biological fluids

A two-step sample preparation technique based on dispersive micro solid-phase extraction combined with coacervative microextraction is presented for preconcentration and determination of tricyclic antidepressant drugs in biological samples. An important feature of the method is the application of hydrophobic magnetic nanoparticles, which in combination with coacervative microextraction method enables development of rapid and efficient extraction procedure in order to achievement of a high extraction efficiency. Simultaneous optimization by experimental design lead to improvement of method with low cost which supply useful information about interaction among variables. Under the optimized conditions, a linear range of 5-1000ngmL(-1) with detection limits from 0.51 to 1.4ngmL(-1) were obtained for target analytes. The method was successfully used for the determination of analytes in biological fluids (plasma and urine) with relative recoveries in the range of 89-105% (RSDs<3.5%).