On-line In-tube Solid-phase Microextraction Research Articles

Silver nanoparticle-functionalized melamine-formaldehyde aerogel for online in-tube solid-phase microextraction of polycyclic aromatic hydrocarbons followed by HPLC-DAD analysis

Based on the π-metal interaction between silver nanoparticles (AgNPs) and aromatic compounds, AgNPs were in-situ grown to melamine-formaldehyde (MF) aerogel for improving the extraction performance to polycyclic aromatic hydrocarbons (PAHs). The AgNPs/MF aerogel was regulated through varing the concentration of reactants, and characterized by scanning electron microscopy, X-ray photoelectron spectroscopy and X-ray powder diffraction. As a new extraction coating, the AgNPs/MF aerogel was coated to stainless-steel wires for in-tube solid-phase microextraction (IT-SPME). The extraction effects of MF aerogels before and after the modification of AgNPs were compared, and the AgNPs greatly improved the extraction ability for PAHs reaching to 166.4 %. Combining IT-SPME with high performance liquid chromatographic detection, an online analytical system was constructed. Furthermore, the sampling volume and rate, concentration of organic solvent, and desorption time were optimized factor by factor. The online analytical method with low detection limits (0.003–0.010 μg L−1) and efficient enrichment factors (1998–3237) for PAHs was established, which fastly detected trace level of PAHs in drinking and environmental water samples. Compared with other methods, the method was comparable or better in the detection limit and linear range, indicating prospective application of the AgNPs/MF aerogel for sample preparation.

Simultaneous analysis of carcinogenic N-nitrosamine impurities in metformin tablets using on-line in-tube solid-phase microextraction coupled with liquid chromatography-tandem mass spectrometry

Contamination of active pharmaceutical ingredients (APIs) and pharmaceutical preparations with carcinogenic N-nitrosamines has led to recalls of these products and supply shortages to patients. The present study describes the development of a highly sensitive method for simultaneous analysis of seven N-nitrosamines using on-line in-tube solid-phase microextraction (IT-SPME) coupled with liquid chromatography-tandem mass spectrometry (LC-MS/MS) to determine their actual contamination in metformin tablets. Using a Carboxen 1006 PLOT capillary as the extraction device for IT-SPME, these compounds were efficiently extracted and concentrated 6‒24-fold by subjecting 40 µL of sample to 25 repeated draw/eject cycles at a rate of 0.2 mL/min. The seven N-nitrosamines were separated within 11 min by gradient elution with 0.1 % formic acid solution and acetonitrile as the mobile phase using a CAPCELL PAK C18 MGII column and detected by multiple reaction monitoring in positive ion mode. The calibration curve showed linearity in the range 0.2‒50 ng/mL and detection limits (S/N = 3) in the range 3‒112 pg/mL. The intra-day and inter-day precisions were less than 5.5 % and 7.0 % (n = 6), respectively, with accuracies ranging from 93‒117 %. Following ultrasonic extraction with water, centrifugation and filtration of the supernatant liquid through a membrane filter, the N-nitrosamine impurities in metformin tablets could be analyzed by IT-SPME/LC‒MS/MS. Their limits of quantification (S/N = 10) were 0.1‒5.1 pg/mg API and recoveries ranged from 87‒102 %. Analysis of eight metformin tablets from eight manufacturers showed that 5.8‒7.5 pg/mg N-nitrosodimethylamine were present in three tablets, with no other N-nitrosamines detected in any of the eight tablets. This method may be useful in testing for N-nitrosamine impurities in pharmaceutical preparations.

Electrochemically deposition of metal-organic framework onto carbon fibers for online in-tube solid-phase microextraction of non-steroidal anti-inflammatory drugs

Electrochemical deposition has been proposed as a promising approach for in situ immobilization of metal-organic framework (MOF) on conductive surfaces. It is favorable as it is time-saving, green, and does not require vigorous reaction conditions, which can be applied to the synthesis and immobilization of extraction materials for fiber in-tube solid phase microextraction. In this work, PPF-1 was immobilized on the surface of the carbon fibers by electrochemical method. The novel method overcame the problems including strict conditions and time-consuming operation. The modified carbon fibers were packed into the PEEK tube for extraction and analysis of three non-steroidal anti-inflammatory drugs (NSAIDs), which performed good extraction efficiency due to strong hydrogen bonding, hydrophobic interaction and π-π interaction between PPF-1 and analytes. The established method obtained good enrichment performance (enrichment factor between 230-540), low limits of detection (between 0.01-0.03 ng/mL), good linearity and good reproducibility (RSDs≤4.93%), which was successfully applied for the quantitative analysis of NSAIDs in human plasma samples.

Smart Titanium Wire Used for the Evaluation of Hydrophobic/Hydrophilic Interaction by In-Tube Solid Phase Microextraction.

Evaluation of the hydrophobic/hydrophilic interaction individually between the sorbent and target compounds in sample pretreatment is a big challenge. Herein, a smart titanium substrate with switchable surface wettability was fabricated and selected as the sorbent for the solution. The titanium wires and meshes were fabricated by simple hydrothermal etching and chemical modification so as to construct the superhydrophilic and superhydrophobic surfaces. The micro/nano hierarchical structures of the formed TiO2 nanoparticles in situ on the surface of Ti substrates exhibited the switchable surface wettability. After UV irradiation for about 15.5 h, the superhydrophobic substrates became superhydrophilic. The morphologies and element composition of the wires were observed by SEM, EDS, and XRD, and their surface wettabilities were measured using the Ti mesh by contact angle goniometer. The pristine hydrophilic wire, the resulting superhydrophilic wire, superhydrophobic wire, and the UV-irradiated superhydrophilic wire were filled into a stainless tube as the sorbent instead of the sample loop of a six-port valve for on-line in-tube solid-phase microextraction. When employed in conjunction with HPLC, four kinds of wires were comparatively applied to extract six estrogens in water samples. The optimal conditions for the preconcentration and separation of target compounds were obtained with a sample volume of 60 mL, an injection rate of 2 mL/min, a desorption time of 2 min, and a mobile phase of acetonile/water (47/53, v/v). The results showed that both the superhydrophilic wire and UV-irradiated wire had the highest extraction efficiency for the polar compounds of estrogens with the enrichment factors in the range of 20–177, while the superhydrophobic wire exhibited the highest extraction efficiency for the non-polar compounds of five polycyclic aromatic hydrocarbons (PAHs). They demonstrated that extraction efficiency was mainly dependent on the surface wettability of the sorbent and the polarity of the target compounds, which was in accordance with the molecular theory of like dissolves like.

Polyhedral Oligomeric Silsesquioxane–Based Hybrid Monolithic Column On-line In-Tube Solid-Phase Microextraction Coupled with High-Performance Liquid Chromatography for the Determination of Five Phthalate Esters in Bottled Water

Polyhedral Oligomeric Silsesquioxane–Based Hybrid Monolithic Column On-line In-Tube Solid-Phase Microextraction Coupled with High-Performance Liquid Chromatography for the Determination of Five Phthalate Esters in Bottled Water

A novel polyhedral oligomeric silsesquioxane-based hybrid monolith as a sorbent for on-line in-tube solid phase microextraction of bisphenols in milk prior to high performance liquid chromatography-ultraviolet detection analysis

An on-line in-tube solid-phase microextraction (in-tube SPME) coupled with high-performance liquid chromatography (HPLC) method was proposed based on a novel polyhedral oligomeric silsesquioxane (POSS)-hybrid monolith for the determination of four bisphenols (BPs) in milk. The monolith was synthesized using acrylamide (AM) and monomethacrylate-functionalized POSS (mono-MA-POSS) as functional monomers to copolymerize with ethylene dimethacrylate (EDMA). Due to the abundant hydrogen bonding, π-π and hydrophobic interaction sites, the synthetic monolith displayed satisfying extraction performance for target BPs. Under the optimized conditions, the developed on-line in-tube SPME-HPLC method exhibited low limits of detection (LODs) (0.030–0.055 ng mL−1). The spiked recoveries were between 85.4 % and 111.8 %, and the relative standard deviations (RSDs) were less than 3.5 % for all the analytes. The results showed that the proposed method provided alternative for the analysis of BPs in complex samples.

Dendritic mesoporous silica nanospheres@porous carbon for in-tube solid-phase microextraction to detect polycyclic aromatic hydrocarbons in tea beverages

It is pretty necessary to detect effectively polycyclic aromatic hydrocarbons (PAHs, including naphthalene, acenaphthylene, acenaphthene, fluorene, phenanthrene, anthracene, fluoranthene, and pyrene) in foods due to their widespread distribution, trace concentration, and harmful risk to humans beings. Herein, dendritic mesoporous silica nanospheres@porous carbon was developed for solid-phase microextraction of PAHs. Firstly, three-dimensional dendritic mesoporous silica nanospheres (DMSNs) with high surface area and large pore volume were synthesized via an oil–water biphase stratification approach, then porous carbon was further prepared by utilizing DMSNs and asphalt as the template and carbon source, respectively. A core–shell DMSNs@porous carbon material was successfully developed and characterized by Raman spectroscopy, elemental analysis, Brunauer-Emmett-Teller test, scanning electron microscopy, and transmission electron microscopy. DMSNs@porous carbon was proved to be a potential extraction material based on large surface area (442 m2 g−1), suitable pore sizes (about 45 nm), and high carbon content (17.36%). Subsequently, it was developed as an extraction coating and applied to online in-tube solid-phase microextraction of PAHs from tea beverages. Through coupling with high-performance liquid chromatography, an analytical method was established under optimal extraction conditions and desorption, low limits of detection (0.010–0.070 μg L−1), wide linear ranges in 0.033–10 μg L−1, and excellent correlation coefficients (most of the r reach 0.999) were received. The relative standard deviations (RSDs, n = 3) of intra-day test and inter-day test were obtained corresponding to the ranges of 0.1–2.5% and 1.0–4.1%. Finally, the method was used for detecting trace PAHs in different tea beverages from the market.

Graphene oxide-functionalized mesoporous silica for online in-tube solid-phase microextraction of polycyclic aromatic hydrocarbons from honey and detection by high performance liquid chromatography-diode array detector

In order to develop an online detection method for polycyclic aromatic hydrocarbons (PAHs) in honey, graphene oxide-functionalized mesoporous silica was prepared and introduced as the coating in the field of in-tube solid-phase microextraction. An extraction tube was coupled to high performance liquid chromatography with diode array detector, and the online analytical system was constructed. After the main extraction and desorption conditions were optimized, a sensitive and online method based on matrix-matched calibration was established towards trace PAHs in honey. The method exhibited wide linear range from 0.8 ng g−1 to 250 ng g−1 and low detection limit of 0.25 ng g−1, and the enrichment effect reached 2719. The proposed method was validated and successfully applied to the analysis of six honey samples. The extraction tube showed good durability and acceptable chemical stability during the experiment.

Online In-Tube Solid-Phase Microextraction Coupled to Liquid Chromatography-Tandem Mass Spectrometry for the Determination of Tobacco-Specific Nitrosamines in Hair Samples.

Active and passive smoking are serious public health concerns Assessment of tobacco smoke exposure using effective biomarkers is needed. In this study, we developed a simultaneous determination method of five tobacco-specific nitrosamines (TSNAs) in hair by online in-tube solid-phase microextraction (SPME) coupled to liquid chromatography-tandem mass spectrometry (LC–MS/MS). TSNAs were extracted and concentrated on Supel-Q PLOT capillary by in-tube SPME and separated and detected within 5 min by LC–MS/MS using Capcell Pak C18 MGIII column and positive ion mode multiple reaction monitoring systems. These operations were fully automated by an online program. The calibration curves of TSNAs showed good linearity in the range of 0.5–1000 pg mL–1 using their stable isotope-labeled internal standards. Moreover, the limits of detection (S/N = 3) of TSNAs were in the range of 0.02–1.14 pg mL–1, and intra-day and inter-day precisions were below 7.3% and 9.2% (n = 5), respectively. The developed method is highly sensitive and specific and can easily measure TSNA levels using 5 mg hair samples. This method was used to assess long-term exposure levels to tobacco smoke in smokers and non-smokers.

Triazine-based covalent porous organic polymer for the online in-tube solid-phase microextraction of polycyclic aromatic hydrocarbons prior to high-performance liquid chromatography-diode array detection

A triazine-based covalent organic porous polymer (COP) was synthesized from the monomers 1,3,5-triphenylbenzene and tricyanogen chloride via the Friedel-Crafts reaction and characterized in detail using Brunauer-Emmett-Teller analysis, X-ray photoelectron spectroscopy, elemental analysis, and scanning electron microscopy, which confirmed that the COP had a rough surface and suitable extraction site. It was then employed in in-tube solid-phase microextraction combined with a high-performance liquid chromatography-diode array detector. The COP adsorbent was evaluated with different types of analyte, including estrogens, polycyclic aromatic hydrocarbons (PAHs), and plasticizers. The COP produced its best performance with PAHs. In order to obtain the highest extraction efficiency for PAHs, the main influential factors were optimized. Furthermore, a sensitive analytical method was established with the limits of detection of 0.004-0.010 µg L−1, high enrichment factor of 1110-2763, and wide linear ranges (0.013-20.0 µg L−1, 0.016-20.0 µg L−1 and 0.033-20.0 µg L−1). The relative standard deviation in intra-day and inter-day tests was also controlled to be within 0.3-3.1%. The proposed method was employed in the online detection of trace PAHs in real water samples, with satisfactory results obtained.

Corncob biochar as a coating for trace analysis of polycyclic aromatic hydrocarbons in water samples by online in-tube solid-phase microextraction coupled to high performance liquid chromatography

Biochar materials have been focused on enormous attention in the fields of capacitance, catalysis, adsorption due to its renewability, abundant in content and widespread distribution. In this work, corncob biochar materials were prepared under different carbonized temperature and characterized by scanning electron microscopy and Raman spectroscopy for surface morphology and graphitization degree. Then the materials were separately attached onto stainless steel wires as the coatings for solid-phase microextraction (SPME). Four wires with the same coating were placed into a polyetheretherketone tube to develop several extraction tubes. Coupled to high performance liquid chromatography (HPLC) with diode array detector (DAD), the tubes were evaluated using several polycyclic aromatic hydrocarbons (PAHs) as model analytes. According to the comparison of extraction efficiency, the best tube was selected. To achieve high sensitivity, both main extraction and desorption processes were optimized. Under the optimum conditions, an in-tube SPME-HPLC-DAD method for PAHs was established with low limits of detection (0.003–0.030 ng mL−1), wide linear ranges (0.010–15 ng mL−1, 0.017–15 ng mL−1, 0.033–15 ng mL−1 and 0.099–15 ng mL−1), high enrichment factors (1864–2615) and acceptable repeatability (relative standard deviations (RSDs, n = 3) less than 2.9% and 6.7% for intra-day and inter-day tests). Furthermore, the accuracy of the method was investigated via analyzing trace PAHs in real water samples and good recoveries (81.7%-116.8%) were obtained. In addition, the extraction tube exhibited satisfactory durability and chemical stability (RSDs ≤ 8.0%, n = 3) and acceptable reproducibility (RSD ≤ 7.8%, n = 3).

Cotton thread modified with ionic liquid copolymerized polymer for online in-tube solid-phase microextraction and HPLC analysis of nonsteroidal anti-inflammatory drugs.

Cotton fiber is a biodegradable material that possesses properties such as high specific area, adjustable shape, and hygroscopicity. In this work, organic polymer was directly in situ grown on the surface of cotton thread and packed into a poly(ether ether ketone) tube for online in-tube solid-phase microextraction. The novel strategy solves the problems like high backpressure and tedious optimization process of normal monolithic polymer-based in-tube solid-phase microextraction capillary. The quaternary ammonium typed ionic liquid of 1-allyl-methylimidazolium chloride, 4-vinylbiphenyl, and ethylene dimethacrylate were co-polymerized and in situ grown on the surface of cotton thread as extraction phase. The solid-phase microextraction tube showed excellent performance for the extraction of three nonsteroidal anti-inflammatory drugs including ketoprofen, naproxen, and flurbiprofen due to the strong ion exchange and hydrophobic interactions. After online coupling with a high-performance liquid chromatography system by six-port valve, the method was applied for the quantitative analysis of nonsteroidal anti-inflammatory drugs in human plasma samples showing good enrichment performance (enrichment factor between 263 and 279), high sensitivity, good linearity, and good reproducibility.

Flower-like layered double hydroxide-modified stainless-steel fibers for online in-tube solid-phase microextraction of Sudan dyes.

Layered double hydroxides are a family of inorganic crystals that have gained a lot of attention due to its special structure and properties such as high porosity, large specific area, and excellent anion exchange ability. In this work, flower-like NiAl-layered double hydroxides with high specific area were in situ immobilized onto the stainless steel fibers by bioinspired polydopamine modification method and packed into poly (ether ether) ketone tube for online solid-phase microextraction with high performance liquid chromatography analysis. Thanks to the high specific surface area and excellent extraction ability of the NiAl-layered double hydroxides, the fibers showed excellent extraction performance to three Sudan dyes with enrichment factors between 260 to 650 folds. After optimization of the reaction and extraction conditions, an online solid-phase microextraction method was developed for determination of Sudan dyes in water samples and chili samples. The method has limits of detection of 0.01 to 0.02ng/mL, good linearity and good reproducibility (≤1.45%).

On-line in-tube solid phase microextraction coupled to capillary liquid chromatography-diode array detection for the analysis of caffeine and its metabolites in small amounts of biological samples

In-tube solid phase microextraction (IT-SPME) coupled on-line to capillary liquid chromatography with diode array detection provides a simple and fast analytical methodology for the simultaneous quantitation of caffeine and its three primary metabolites (theobromine, paraxanthine and theophylline) in micro samples of serum, saliva and urine matrices. The sample amount required for one analysis was only 2.5 μL of saliva, 6.25 μL of serum or 40 μL of urine, a requirement for its implementation in a hospital laboratory for preterm newborns, where sample availability is a major problem. In standard conditions, 25 μL of diluted saliva or serum (or 100 μL of urine) were processed by IT-SPME in 30 cm of commercially available capillary GC column coated with ZB-FFAP (100% nitroterephthalic modified polyethylene glycol). The retained compounds were desorbed from the IT-SPME capillary by the mobile phase (a gradient mixture of water and methanol) and the separation was carried out in a C18 column (150 mm × 0.5 mm i.d., 5 μm particle size). Analytes eluted before 14 min, at a flow rate of 15 μL min−1, and were detected by absorbance at 275 nm. The calibration graphs presented good linearity (R2 > 0.99), without the presence of matrix effect, and recoveries between 84 and 112% were obtained. Limits of detection (S/N = 3) were 0.1 μg·mL−1 in serum and 0.5 μg·mL−1 in saliva and urine samples, for all compounds, and the intra- and inter-day variation coefficients (n = 3) were between 3 and 17%. Analytical figures of merit were similar to those proposed by other methodologies, but using lower sample volume and a faster and simpler sample treatment and analysis. Paired samples of serum and saliva from preterm newborns treated with caffeine at the pediatric intensive care unit were analyzed by the method, with statistically equivalent results for caffeine concentrations.

Determination of PAHs content in hair samples of smokers and non-smokers using gas chromatography in hyphenation with mass spectrometry

Abstract: PAHs are known as toxic, persistent organic pollutants produced by incomplete combustion of organic materials including smoking. To assess the exposure of PAHs through smoking habits, 16 PAHs in hair samples of 32 smokers and 20 non-smokers were analyzed using gas chromatography in hyphenation with mass spectrometry. The results showed that total content of PAHs in hair samples of smokers ranged from 46.8 ng/g to 1,257 ng/g (mean: 388.3 ng/g) and that of non-smokers ranged from 65.3 ng/g to 910.8 ng/g (mean: 266.1 ng/g). Application of the Student statistical method indicated that the dataset of PAHs in hair samples between two subject groups were significantly different. Phenanthrene, pyrene, fluoranthene were the most dominant PAHs in hair samples of both smokers and non-smokers. The mean content of total toxicity equivalent of 16 PAHs compared to benzo (a) pyrene in hair samples of smokers and non-smokers were 13.32 ng/g and 11.29 ng/g, respectively. Some considerable values of PAHs including PAH4, PAH8 and BaPeq were higher than other similar studies in the world except one study in Japan. The analysis of PAHs in a new biomarker such as hair samples is a potential research trend to assess the exposure of PAHs in the human body.
 Keywords: PAHs, hair sample, smoker, non-smoker.
 References
 [1] World Health Ozganization, 1998. Selected Non-Heterocyclic Polycyclic Aromatic Hydrocacbons, Geneva. https://monographs.iarc.fr/ wp-content/uploads/2018/06/mono92-14.pdf.[2] L. Duedahl-Olesen, M. Aaslyng, L. Meinert, T. Christensen, A.H. Jensen, M.-L. Binderup, Polycyclic aromatic hydrocarbons (PAH) in Danish barbecued meat, Food Control 57 (2015) 169-176. https://doi.org/10.1016/j. foodcont. 2015.04.012.[3] O. Santino, P.C. Viviana, C. Loredana, Polycyclic aromatic hydrocarbons (PAHs) in coffee brew samples: analytical method by GC–MS, profile, levels and sources, food and chemical toxicology 47 (4) (2009) 819-826. https://doi.org/10.1016/j.fct.2009.01.011.[4] L. Duedahl-Olesen, M.A. Navaratnam, J. Jewula, and A. H. Jensen, PAH in Some Brands of Tea and Coffee, Polycyclic Aromatic Compounds 35 (2015) 74–90. https://doi.org/ 10.1080/10406638.2014.918554.[5] F. J. van Schooten, E. J. C. Moonen, L. van der Wal, P. Levels, J.C.S. Kleinjans, Determination of Polycyclic Aromatic Hydrocarbons (PAH) and Their Metabolites in Blood, Feces, and Urine of Rats Orally Exposed to PAH Contaminated Soils, Archives of Environmental Contamination and Toxicology 33 (3) (1997) 317–322. https://doi.org/ 10.1007/ s00 2449900259[6] E. Nethery, A.J. Wheeler, M. Fisher, A. Sjödin, Z. Li, L.C. Romanoff, W. Foster, T.E. Arbuckle, Urinary polycyclic aromatic hydrocarbons as a biomarker of exposure to PAHs in air: a pilot study among pregnant women, J Expo Sci Environ Epidemiol. 22 (1) (2012) 70-81. https:// doi. org/10.1038/jes.2011.32.[7] Bộ Y tế, Chương trình phòng chống tác hại của thuốc lá quốc gia, 2015. http://vinacosh.gov.vn/ vi/hoat-dong/tai-lieu-truyen thong/2015/07/81E 20103/to-thong-tin-ve-tac-hai-cua-thuoc-la.[8] Y. Yamamoto, A. Ishizaki, H. Kataoka, Biomonitoring method for the determination of polycyclic aromatic hydrocarbons in hair by online in-tube solid-phase microextraction coupled with high performance liquid chromatography and fluorescence detection, J. Chromatogr. B Anal. Technol. Biomed. Life Sci. 1000 (2015) 187–191. https://doi.org/10.1016/ j.jchromb.2015.07.033.[9] A. Toriba, Y. Kuramae, T. Chetiyanukornkul, R. Kizu, T. Makino, H. Nakazawa, K. Hayakawa, Quantification of polycyclic aromatic hydrocarbons (PAHs) in human hair by HPLC with flourescence detection: A biological monitoring method to evaluate the exposure to PAHs, Biomedical Chromatography, 17 (2-3) (2003) 126-32. https://doi.org/10.1002/bmc.222.[10] P. Palazzi, S. Mezzache, N. Bourokba, E.M. Hardy, A. Schritz, P. Bastien, C. Emond, J. Li, J. Soeur, B.M.R. Appenzeller, Exposure to polycyclic aromatic hydrocarbons in women living in the Chinese cities of BaoDing and Dalian revealed by hair analysis, Environ Int., 121 (Pt 2) (2018) 1341-1354. https://doi.org/ 10.1016/j.envint.2018.10.056[11] W. Wang, F. Wu, J. Zheng, M.H. Wong, Risk assessments of PAHs and Hg exposure via settled house dust and street dust, linking with their correlations in human hair, J Hazard Mater. 263 Pt 2 (2013) 627-37. https://doi.org/10.1016/ j.jhazmat.2013.10.023.[12] Z. Li, B. Wang, S. Ge, L. Yan, Y. Liu, Z. Li, A. Ren, A simultaneous analysis method of polycyclic aromatic hydrocarbons, nicotine, cotinine and metals in human hair, Environ Pollut. 219 (2016) 66-71. https://doi.org/10. 1016/j.envpol.2016.09.045.[13] I.C.T. Nisbet and P.K. LaGoy, Toxic equivalency factors (TEFs) for polycyclic aromatic hydrocarbons (PAHs), Regul. Toxicol. Pharmacol. 16 (3) (1992) 290-300. https://doi.org/ 10.1016/0273-2300(92)90009-X.

A sensitive method for the determination of tobacco-specific nitrosamines in mainstream and sidestream smokes of combustion cigarettes and heated tobacco products by online in-tube solid-phase microextraction coupled with liquid chromatography-tandem mass spectrometry

A simple and sensitive method, using automated online in-tube solid-phase microextraction (SPME) coupled with liquid chromatography-tandem mass spectrometry (LC-MS/MS), was developed for the determination of four tobacco-specific nitrosamines (TSNAs) in mainstream and sidestream smoke of combustion cigarettes and heated tobacco products. These TSNAs were separated within 4 min on a Capcell Pak C18 MGⅢ column and detected in the positive ion mode by multiple reaction monitoring. The optimum in-tube SPME conditions were 30 draw/eject cycles of 40 μL of sample at a flow rate of 200 μL min−1 using a Supel-Q PLOT capillary column as an extraction device. The extracted TSNAs were easily desorbed from the column by passage of the mobile phase, with no carryover observed. This in-tube SPME LC–MS/MS method showed good linearity for four TSNAs in the 0.5–100 pg mL−1 ranges, with correlation coefficients above 0.9998 (n = 24), using stable isotope-labeled TSNAs as internal standards. The validation assays for limit of detection, limit of quantification, specificity, precision and accuracy of the analytes were consistent with the requirements recommended by the ICH guidelines. The validated method was utilized successfully to analyze four TSNAs in mainstream and sidestream smoke samples without any interference peaks. Overall recoveries of TSNAs spiked into smoke sample solutions were 97.3–104.6%. The developed method can automate the extraction, concentration and analysis of samples, and is sensitive and selective for TSNAs. This method was used to analyze TSNAs in mainstream and sidestream smoke samples of several commercially available combustion cigarettes and heated tobacco products.

Simultaneous HPLC-MS determination of 8-hydroxy-2'-deoxyguanosine, 3-hydroxyphenanthrene and 1-hydroxypyrene after online in-tube solid phase microextraction using a graphene oxide/poly(3,4-ethylenedioxythiophene)/polypyrrole composite.

The exploration of monohydroxy polycyclic aromatic hydrocarbons and 8-hydroxy-2'-deoxyguanosine (8-OHdG) produced by oxidative stress and DNA damage is a powerful and non-invasive tool to study the health risk of exposure to polycyclic aromatic hydrocarbons (PAHs). A nanocomposite prepared from graphene oxide, poly(3,4-ethylenedioxythiophene) and polypyrrole was electrodeposited on the internal surface of a stainless-steel tube for online in-tube solid phase microextraction (IT-SPME) of 8-OHdG, 3-hydroxyphenanthrene and 1-hydroxypyrene from urine. The coating possesses excellent chemical and mechanical stability, high extraction efficiency, good resistance to matrix interference, and a long lifespan. An online IT-SPME-high performance liquid chromatography-mass spectrometry method was developed for the determination of these three metabolite biomarkers in human urine. Figures of merit include (a) enrichment factors of 30-48; (b) low limits of detection (4-41pg·mL-1 at S/N = 3); (c) wide linear ranges (0.05-50ng·mL-1); (d) good recoveries from spiked samples (71.6-109.5%); and (e) acceptable repeatability (2.3-14.6%). The method offers the advantages of low cost, simplicity, sensitivity, rapidity and automation. Graphical abstract Schematic illustration of online in-tube solid phase microextraction using graphene oxide/poly(3,4-ethylenedioxythiophene)/polypyrrole composites as adsorbent in astainless-steel (SS) tubefor the enrichment and simultaneous determination of 8-hydroxy-2'-deoxyguanosine, 3-hydroxyphenanthrene and 1-hydroxypyrene prior to HPLC-MS analysis.

Estimating Diphenylamine in Gunshot Residues from a New Tool for Identifying both Inorganic and Organic Residues in the Same Sample

A method involving the collection and determination of organic and inorganic gunshot residues on hands using on-line in-tube solid-phase microextraction (IT-SPME) coupled to miniaturized capillary liquid chromatography with diode array detection (CapLC-DAD) and scanning electron microscopy coupled to energy dispersion X-ray (SEM-EDX), respectively, for quantifying both residues was developed. The best extraction efficiency for diphenylamine (DPA) as the main target among organic residues was achieved by using a dry cotton swab followed by vortex-assisted extraction with water, which permits preservation of inorganic residues. Factors such as the nature and length of the IT-SPME extractive phase and volume of the sample processed were investigated and optimized to achieve high sensitivity: 90 cm of TRB-35 (35% diphenyl, 65% polydimethylsiloxane) capillary column and 1.8 mL of the processed sample were selected for the IT-SPME. Satisfactory limit of detection of the method for analysis of DPA deposited on shooters’ hands (0.3 ng) and precision (intra-day relative standard deviation, 9%) were obtained. The utility of the described approach was tested by analyzing several samples of shooters’ hands. Diphenylamine was found in 81% of the samples analyzed. Inorganic gunshot residues analyzed by SEM-EDX were also studied in cotton swab and lift tape kit samplers. Optical microscopy was used to see the inorganic gunshot residues in the cotton swab samplers. The lift tape kits provided lesser sensitivity for DPA than dry cotton swabs—around fourteen times. The possibility of environmental and occupational sources could be eliminated when DPA was found together with inorganic residues. Then, the presence of inorganic and organic residues in a given sample could be used as evidence in judicial proceedings in the forensic field.

Butyl Methacrylate-Co-Ethylene Glycol Dimethacrylate Monolith for Online in-Tube SPME-UHPLC-MS/MS to Determine Chlopromazine, Clozapine, Quetiapine, Olanzapine, and Their Metabolites in Plasma Samples.

This manuscript describes a sensitive, selective, and online in-tube solid-phase microextraction coupled with an ultrahigh performance liquid chromatography-tandem mass spectrometry (in-tube SPME-UHPLC-MS/MS) method to determine chlopromazine, clozapine, quetiapine, olanzapine, and their metabolites in plasma samples from schizophrenic patients. Organic poly(butyl methacrylate-co-ethylene glycol dimethacrylate) monolith was synthesized on the internal surface of a fused silica capillary (covalent bonds) for in-tube SPME. Analyte extraction and analysis was conducted by connecting the monolithic capillary to an UHPLC-MS/MS system. The monolith was characterized by scanning electron microscopy (SEM) and Fourier transform infrared spectrometry (FTIR). The developed method presented adequate linearity for all the target antipsychotics: R2 was higher than 0.9975, lack-of-fit ranged from 0.115 to 0.955, precision had variation coefficients lower than 14.2%, and accuracy had relative standard error values ranging from −13.5% to 14.6%, with the exception of the lower limit of quantification (LLOQ). The LLOQ values in plasma samples were 10 ng mL−1 for all analytes. The developed method was successfully applied to determine antipsychotics and their metabolites in plasma samples from schizophrenic patients.

Polymeric ionic liquid open tubular capillary column for on-line in-tube SPME coupled with UHPLC-MS/MS to determine endocannabinoids in plasma samples

This manuscript describes the development of wall-coated open tubular capillary column with polymeric ionic liquids (PILs) for on-line in-tube solid phase microextraction coupled with ultra high-performance liquid chromatography tandem mass spectrometry (in-tube SPME/UHPLC-MS/MS) to determine anandamide (AEA) and 2-arachidonoyl glycerol (2 A G) in plasma samples. Selective PILs were synthetized from the [VC6IM][Cl], [VC16IM][Br], and [(VIM)2C10]2 [Br] - ionic liquids - by in-situ thermal-initiated polymerization in a fused silica capillary column for in-tube SPME. The synthesis procedure was optimized, and the capillary columns were characterized using spectroscopic and chromatography techniques. The chemically bonded and cross-linked PIL-based sorbent phase (thickness coating: 1.7 μm) presented high chemical and mechanical stability. Among the sorbents evaluated, the PIL-based capillary, [VC16IM][Br]/[(VIM)2C10]2 [Br] presented the best performance with a sorption capacity of 37,311 ng cm−3 and 48,307 ng cm−3 for AEA and 2 A G, respectively. This capillary was reused more than ninety times without significant changes in extraction efficiency. The in-tube SPME-UHPLC-MS/MS method presented a linear range from 0.1 ng mL−1 to 100 ng mL−1 for AEA, and from 0.05 ng mL−1 to 100 ng mL−1 for 2 A G, with coefficients of determination higher than 0.99, p-value for Lack-of-fit test higher than 0.05 (α of 0.05), precision with coefficient of variation (CV) values ranging from 1.6 to 14.0% and accuracy with relative standard deviation (RSD) values from −19.6% to 13.2%. This method was successfully applied to determine AEA and 2 A G in plasma patients with Parkinson's disease. The concentrations in these plasma samples ranged from 0.14 to 0.46 ng mL−1 for AEA and from <0.05 ng mL−1 to 0.51 ng mL−1 for 2-AG.