SPME-HPLC Method Research Articles

Multivariate surface self-assembly strategy to fabricate ionic covalent organic framework surface grafting monolithic sorbent for enrichment of aristolochic acids prior to high performance liquid chromatography analysis

Herein, an ionic covalent organic framework (iCOF) surface grafting monolithic sorbent was prepared by the multivariate surface self-assembly strategy for in-tube solid-phase microextraction (SPME) of trace aristolochic acids (AAs) in serum, traditional Chinese medicines (TCMs) and Chinese patent drug. Via adjusting the proportion of ionic COF building block during the self-assembly, the density of quaternary ammonium ions in the iCOF was modulated for the enhanced adsorption of AAs. The successful preparation of iCOF surface grafting monolithic sorbent was confirmed by different means. A multiple mode mechanism involving π-π stacking, hydrophobic, electrostatic and hydrogen-bonding interactions was primarily attributed to the adsorption. Several in-tube SPME operating conditions, such as the dosage of ionic COF building block, ACN percentage and TFA percentage in the sampling solution, ACN percentage and TFA percentage in eluent and the collection time span, were optimized to develop the online in-tube SPME-HPLC method for analysis of AAs. Under the optimized conditions, a good linearity was obtained in the concentration range of 20–1000 ng/mL for target AAs in serum samples, the limits of detection (LODs) were less than 10 ng/mL, while the recoveries ranged from 90.3 % to 98.7 % with RSDs (n = 5) below 7.9 %. This study developed a feasible approach to iCOF functionalized monolithic sorbent for SPME and further exhibited the vast potential for the application of COF based monolithic sorbent in sample preparation.

Covalent organic framework-based monolithic column with hydrophilic and π-π stacking interaction for efficient in-tube solid-phase microextraction of synthetic phenolic antioxidants

Currently, covalent organic framework-based (COF-based) monolithic columns show excellent application potential for high-efficient sorbent in sample preparation. Hydrophobic and π-π stacking interaction were their primary adsorption mechanisms for extraction. Hydrophilic interaction has not been involved yet. Herein, a novel COF-based monolithic column with hydrophilic interaction and π-π stacking interaction has been fabricated by the embedment of COFTAPB-TPA microspheres into urea–formaldehyde resin (UF) monolith. Due to the excellent adhesion performance of UF, the COFTAPB-TPA microspheres could be steadily embedded into the UF monolith. Taking the advantages of the hydrophilic interaction and the π-π stacking interaction between the COFTAPB-TPA@UF monolith and synthetic phenolic antioxidants (SPAs), the COFTAPB-TPA@UF monolith was adopted as efficient sorbent for in-tube SPME of trace SPAs in edible oils. Several SPME parameters, including the percentage of ACN in the sampling solution and eluent, the collection time span, and the pH value of the sampling solution, were optimized for satisfactory SPME performance. Under the optimized conditions, the LODs of the analytes varied from 0.2 to 1.2 ng/mL, and the recoveries ranged from 78.1 % to 98.4 % for sunflower oil samples at three spiked levels, with the RSDs lower than 7.2 %, indicating the superior extraction capacity of the COFTAPB-TPA@UF monolith as well as the promising feasibility of the proposed in-tube SPME-HPLC method. This work lighted a facile way for COF-based monoliths with hydrophilic interaction, and further expanded their applications for sample preparation.

Covalent organic framework reinforced hollow fiber for solid-phase microextraction and determination of pesticides in foods

A novel solid-phase micro extraction (SPME) system was constructed by immobilizing a three-dimensional hydroxyl-functionalized covalent organic framework (COF) into the wall pores of hollow fiber (HF). The extractant was sensitive to hydrogen bond acceptors contained analytes. Combined with high performance liquid chromatography (HPLC), a SPME-HPLC method was established for acetamiprid (Ace), dimethipin (Dim), and amitrole (Ami) simultaneous determination from rice and apple samples. Critical extraction parameters were optimized. The analytical method was proved to have good linearity with the linear coefficients above 0.99, satisfactory precision with the RSD less than 4.9%, desirable recovery ranged from 79.3% to 106.8%, and low limit of detection (LOD) ranged from 0.86 to 1.38 ng/g for Ace, Dim, and Ami. The explored analytical method has potentials for hydrogen bond acceptors contained pesticides sensitive and selective determination from food samples. • Covalent organic framework reinforced hollow fiber was explored. • Solid-phase micro extraction coupled with chromatographic method was applied. • Hydrogen bond acceptors contained analytes were selectively extracted. • Acetamiprid, dimethipin, and amitrole were analyzed from food samples.

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.

Polyaniline/titanium dioxide nanorods functionalized carbon fibers for in-tube solid-phase microextraction of phthalate esters prior to high performance liquid chromatography-diode array detection

To improve extraction performance of carbon fibers (CFs) towards phthalate esters (PAEs), titanium dioxide (TiO2) nanorods array was in-situ grown on the surface of CFs, then polyaniline (PANI) was used to modify it. PANI/TiO2 nanorods-CFs were placed into a polyetheretherketone tube for solid-phase microextraction (SPME). Combining the tube to high performance liquid chromatography (HPLC), it was evaluated and displayed good extraction performance for several PAEs. Compared with bare CFs, TiO2 nanorods and PANI, PANI/TiO2 nanorods presented best performance, attributed to the unique advantages between high surface area of TiO2 nanorods and multiple adsorption interactions (like π-π stacking, hydrogen bond) of PANI. After the optimization of the important factors (sampling volume, sampling rate, sample pH, concentrations of organic solvent and salt in sample, and desorption time), the online in-tube SPME-HPLC method was established. It provided low limits of detection (0.01-0.05 μg L−1) and wide linear ranges (0.03-30, 0.10-30, 0.17-30 μg L−1) with correlation coefficients larger than 0.9991. The relative standard deviations (n=6) between intra-day and inter-day tests were in the ranges of 3.5-10.3% and 4.7-13.9%, respectively. The method was successfully used to determine seven PAEs in real water samples. Besides of satisfactory durability, the material also exhibited superior extraction performance than some materials.

Schiff base network-1 incorporated monolithic column for in-tube solid phase microextraction of antiepileptic drugs in human plasma

A novel monolithic column incorporated with Schiff base network-1 (SNW-1) was prepared for in-tube solid phase microextraction (SPME) of antiepileptic drugs. The SNW-1 nanoparticles was synthesized by a solvent thermal method and embedded in the poly(glycidyl methacrylate-ethylene glycol dimethacrylate) (GMA-EGDMA) monolithic column by in situ polymerization. The amount of SNW-1 in polymerization solution for preparation of monolithic column was optimized. Fourier transform infrared spectrometry and scanning electron microscope were used to characterize the obtained monolithic column. The SNW-1-monolithic column was connected to the high-performance liquid chromatography (HPLC) system and applied for online extraction and analysis of antiepileptic drugs. The extraction conditions including sample solution flow rate, desorption time, acetonitrile content, pH of sample solution and sample volume were investigated. Under optimal conditions, the proposed SPME-HPLC method showed high extraction efficiency, good linearity, low limits of detection (0.2 ng/mL) and good repeatability (relative standard deviations < 2.41%). This method was also applied to the analysis of antiepileptic drugs in human plasma samples and the recoveries were in the range of 88.6–106.1% with RSDs less than 3.51%.

A melamine–formaldehyde-resorcinol aerogel as the sorbent of in-tube solid-phase microextraction

Aerogels have attracted more and more attention in many fields due to the unique properties, including large surface area, high porosity, excellent adsorption, and low thermal conductivity. Based on the specific advantages, an organic aerogel was developed as the coating for solid-phase microextraction (SPME) in this work. Melamine-formaldehyde-resorcinol aerogel was in situ prepared on the surface of basalt fibers through the copolymerization reaction, the fibers were placed into a polyetheretherketone tube to achieve SPME tube. Coupled to high performance liquid chromatography (HPLC), the tube was investigated and exhibited good extraction selectivity towards polycyclic aromatic hydrocarbons (PAHs) by π-π stacking and hydrophobic interactions. Under the optimal conditions, an online in-tube SPME-HPLC method was established with satisfactory enrichment factors (1128–2016), wide linear ranges (0.03–30 μg L−1 and 0.15–30 μg L−1), low limits of detection (0.01–0.05 μg L−1) and acceptable repeatability (RSD ≤ 3.9%, n = 5). The method was successfully applied to the determination of several PAH targets in real samples.

An in-tube aptamer/gold nanoparticles coated capillary solid-phase microextraction for separation of adenosine in serum and urine samples

As an endogenous nucleoside, adenosine was significant for the diagnosis and treatment of some diseases, such as schizophrenia. However, due to the complicated matrix interference, it was difficult to monitor trace or ultra-trace adenosine directly in bio-samples. In this contribution, a novel in-tube SPME technique based on aptamer/Au nanoparticles coated open tubular fused-silica capillary was established to separate and enrich adenosine in bio-samples with high affinity. Therefore, a uniform and dense AuNPs layer was coated on the inner surface of the open tubular capillary, and then adenosine aptamer was immobilized on AuNPs with a high capacity of 2.44 μg per 27-cm capillary. As a result, the capillary shown high selectivity to adenosine with a selectivity factor of 14.4 when compared with the scrambled aptamer/AuNPs coated capillary. Also, the extraction amount of adenosine was 2.8–24.8 times higher than those of its structural analogs and contrast, such as guanosine, uridine, cytidine, thymidine, and toluic acid. After the optimization of extraction conditions, the aptamer/AuNPs coated in-tube SPME-HPLC method was developed for the adenosine assay with the linear range of 0.002–0.100 μg mL−1 and the detection limit of 0.45 ng mL−1. Subsequently, the approach was applied for trace adenosine monitoring in human serum and urine samples. It showed a strong performance of reducing matrix interference and improving sensitivity, and the spiking recoveries of 89.9–92.6% and 91.1–94.5% were achieved respectively.

Poly (Octadecyl Methacrylate-Co-Trimethylolpropane Trimethacrylate) Monolithic Column for Hydrophobic in-Tube Solid-Phase Microextraction of Chlorophenoxy Acid Herbicides.

Chlorophenoxy acid herbicides (CAHs), which are widely used on cereal crops, have become an important pollution source in grains. In this work, a highly hydrophobic poly (octadecyl methacrylate-co-trimethylolpropane trimethacrylate) [poly (OMA-co-TRIM)] monolithic column has been specially prepared for hydrophobic in-tube solid-phase microextraction (SPME) of CAHs in rice grains. Due to the hydrophobicity of CAHs in acid conditions, trace CAHs could be efficiently extracted by the prepared monolith with strong hydrophobic interaction. Several factors for online hydrophobic in-tube SPME, including the length of the monolithic column, ACN and trifluoroacetic acid percentage in the sampling solution, elution volume, and elution flow rate, were investigated with respect to the extraction efficiencies of CAHs. Under the optimized conditions, the limits of detection of the four CAHs fell in the range of 0.9–2.1 μg/kg. The calibration curves provided a wide linear range of 5–600 μg/kg and showed good linearity. The recoveries of this method ranged from 87.3% to 111.6%, with relative standard deviations less than 7.3%. Using this novel, highly hydrophobic poly (OMA-co-TRIM) monolith as sorbent, a simple and sensitive online in-tube SPME-HPLC method was proposed for analysis of CAHs residue in practical samples of rice grains.

An effective strategy for controlled fabrication and self-assembled modification of template-supported silica nanosheets on a superelastic nickel-titanium alloy fiber for highly efficient solid-phase microextraction

Silica nanosheets (SiO2NSs) were successfully fabricated on the superelastic nickel-titanium alloy (NiTi) wire as a novel fiber for solid-phase microextraction (SPME). Before sol-gel coating, the NiTi wire was hydrothermally treated in alkaline solution for the in situ growth of NiO/TiO2 nanosheets (NiO/TiO2NSs). The sol-gel coating of SiO2 on the surface of NiO/TiO2NSs template was investigated and a thin shell of SiO2 was found to cover NiO/TiO2NSs, which can enlarge the effective surface area of the SiO2 coating. This SiO2 capped NiO/TiO2NSs coated NiTi (NiTi@NiO/TiO2@SiO2NSs) fiber shows good extraction selectivity for polycyclic aromatic hydrocarbons (PAHs) and enhanced mechanical stability. After the self-assembled modification of SiO2NSs by phenyltrichlorosilane, the NiTi@NiO/TiO2@SiO2NSs@Ph fiber shows higher extraction capability for non-polar PAHs. Thus, the conditions for the extraction of PAHs were investigated and optimized coupled to HPLC with UV detection. Under the optimized conditions, the analytical parameters of the SPME-HPLC methods with the NiTi@NiO/TiO2@SiO2NSs and the NiTi@NiO/TiO2@SiO2NSs@Ph fibers were determined and compared. The SPME-HPLC method with the NiTi@NiO/TiO2@SiO2NSs@Ph fiber was developed for the concentration and the determination of PAHs in environment water samples. The relative recovery of PAHs in real water samples spiked at 5 μg L−1, 10 μg L−1 and 30 μg L−1 ranged from 88.1% to 109%. Furthermore, this fiber is stable due to the chemical bonding between different coatings and NiTi substrates. The fabrication of the NiO/TiO2@SiO2NSs@Ph coating on the NiTi fiber substrate is precisely controllable.

One-pot preparation of an acryloyled β-cyclodextrin-silica hybrid monolithic column and its application for determination of carbendazim and carbaryl

This work describes, for the first time, an acryloyled β-cyclodextrin hybrid monolith column was synthesized, under aqueous-phase conditions, and used for solid-phase microextraction of carbendazim and carbaryl. The monolithic column was characterized using scanning electron microscopy, nitrogen adsorption–desorption, thermogravimetric analysis and Fourier transform infrared spectroscopy, and used as the adsorbent for solid phase microextraction (SPME) of carbendazim and carbaryl. After optimization of the SPME conditions, a simple and sensitive SPME-HPLC method was developed for the determination of carbendazim and carbaryl in leafy vegetables. The method exhibited a good liner response in the range 5–400 μg/kg (R2 = 0.9994) for carbendazim and 10–400 μg/kg (R2 = 0.9996) for carbaryl, respectively. The limits of detection were 1.0 and 1.5 μg/kg for carbendazim and carbaryl, respectively, in leafy vegetables. Recoveries ranged from 92.6% to 110.1%, and the relative standard deviations were less than 6.1%.

Solid phase microextraction with poly(deep eutectic solvent) monolithic column online coupled to HPLC for determination of non-steroidal anti-inflammatory drugs

Polymer monolithic column based on a green deep eutectic solvent (DES) was prepared for in-tube solid phase microextraction of non-steroidal anti-inflammatory drugs (NSAIDs) in aqueous samples. DES composed of choline chloride and itaconic acid was adopted as functional monomer to synthesize a polymeric monolith inside polydopamine-functionalized poly(ether ether ketone) (PEEK) tube. The obtained monolithic column was characterized with fourier transform infrared spectrometry, X-ray photoelectron spectrometer and field emission scanning electron microscope. An online SPME-HPLC method was developed by connecting the PEEK tube to the HPLC system. Parameters including sampling rate, desorption time, sample pH value and sample volume that can affect the performance of this method were investigated. Under the optimized conditions, the proposed SPME-HPLC method showed high extraction efficiency (enrichment factors about 100), good linearity (R ≥ 0.9997) and good reproducibility (relative standard deviation < 4.32%) for determination of three NSAIDs in aqueous solution. The limits of quantification were found to be in a range of 0.05–0.25 ng mL−1. The SPME-HPLC method was also successfully applied to detect NSAIDs in lake water and human plasma samples.

Poly (methacrylic acid-co-diethenyl-benzene) monolithic microextraction column and its application to simultaneous enrichment and analysis of mycotoxins

A poly (methacrylic acid-co-divinyl-benzene) [poly (MAA-co-DVB)] monolithic column was specially prepared according to the chemical structures of the three mycotoxins of aflatoxin B1, zearalenone and sterigmatocystin, and used for in-tube solid-phase microextraction (in-tube SPME) of the selected mycotoxins. The poly (MAA-co-DVB) monolithic column was characterized in detail, and exhibited effective hydrophobic, π-π, and hydrogen bonding interactions towards the target analytes. By coupling the poly (MAA-co-DVB) monolithic column-based in-tube SPME with high-performance liquid chromatography, a simple, sensitive and matrix effect-free method for determination of mycotoxins was developed. Some important parameters related to extraction efficiency were optimized systematically. Under the optimal conditions, the enrichment factors for the three mycotoxins ranged from 71.9 to 98.7. Recoveries of mycotoxins in rice grains with three spiked concentration levels were in the range of 78.0–102.8%, with satisfactory relative standard deviations (n = 4) of 2.96–4.74%. Good linearity was obtained with correlation coefficients larger than 0.99, and the detection limits (S/N = 3) of the three mycotoxins were between 0.69 and 2.03μgkg−1. The developed poly (MAA-co-DVB) monolithic column based in-tube SPME-HPLC method was successfully used to sensitively determine trace mycotoxins in practical samples of rice grain without interference peaks, indicating that it is promising for the detection of trace mycotoxins in complex grain samples.

Simultaneous determination of BTEX and their metabolites using solid-phase microextraction followed by HPLC or GC/MS: An application in teeth as environmental biomarkers

Applications of benzene, toluene, ethylbenzene, and o-, m-, and p-xylenes (BTEX) release them into the environment exposing living organism. These endocrine disruptors are toxic, highly volatile and easily absorbed by the lungs and can cause adverse consequences for the human health as neurological diseases and cancer.A method for the analysis of BTEX and its metabolites (phenols and aromatic acids) in teeth is presented. The method consists in a one-step simple extraction procedure from spiked tooth using NaOH solution followed by SPME-HPLC or HS-SPME-GC/MS determination. Optimization of both, spiking procedure and extraction step of these analytes from tooth, was carried out. Two fibers CAR/PDMS for BTEX and PA for BTEX metabolites were used for the SPME and variables were optimized for analytes at 30°C using spiked solutions. The optimized adsorption times were 30, 75 and 30min and desorption times were 10, 40 and 30min for BTEX, phenols and aromatic acids, respectively. Linearity for SPME-HPLC method was established using spiked solutions with both, BTEX and metabolites, at 2.5, 5.0, 10.0, 25.0μg/mL. The obtained results indicated a good linearity (r2 above 0.994) for all analytes. Triplicate analyses were performed with RSD lower than 15%. LODs were in the range 0.2–33.3ng/mL for SPME-HPLC and 0.06–0.09pg/mL for HS-SPME-GC/MS methods in spiking solutions. Once the method was optimized, bovine teeth were used as biological matrix model for the tuning of spiking and extraction steps. Optimal adsorption and desorption times were 4h for both procedures. Micrograms per tooth gram of BTEX and phenols were quantified in ten human teeth and aromatic acids were not identified.The developed method for BTEX and metabolites analyses using SPME-HPLC or HS-SPME-GC/MS shows good precision, linearity and sensitivity. The method was successfully applied in human teeth as environmental biomarker of BTEX and metabolites.

Preparation of Acryloyl β-Cyclodextrin Organic Polymer Monolithic Column and Its Application in Solid-Phase Microextraction and HPLC Analysis for Carbofuran and Carbaryl in Rice

An acryloyl β-cyclodextrin (A-β-CD) monolithic column for solid-phase microextraction (SPME) and determination of carbofuran and carbaryl by high-performance liquid chromatography (HPLC) have been prepared through a “one-step” polymerization method. The synthesis conditions, including the volume of cross-linker, the ratio and volume of mixed porogenic solvent consisted of methanol and N,N-dimethylformamide were optimized. The prepared monolithic column was characterized by thermogravimeteric analysis (TGA), scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FT-IR), and Brunner-Emmet-Teller (BET) measurement. The eluent type, volume and flow rate, sample volume, flow rate, acidity, and ionic strength were optimized in detail. Under the optimized conditions, a simple, rapid, and sensitive SPME-HPLC method was developed for determination of carbofuran and carbaryl in rice samples. The method yielded a linear calibration curve in the concentration ranges of 1.5–200 μg/kg for carbofuran and 0.3–200 μg/kg for carbaryl with correlation coefficients (R 2) of above 0.9955. Limits of detection (S/N = 3) were 0.5 μg/kg for carbofuran and 0.1 μg/kg for carbaryl, respectively. The recoveries of this method ranged from 88.1 to 105.8%. The relative standard deviations were less than 8.1%.

In-tube solid-phase microextraction based on NH2-MIL-53(Al)-polymer monolithic column for online coupling with high-performance liquid chromatography for directly sensitive analysis of estrogens in human urine

In this work, a novel NH2-MIL-53(Al) incorporated poly(styrene-divinylbenzene-methacrylic acid) (poly(St-DVB-MAA)) monolith was prepared via chemical fabrication. Moreover, it has been efficiently applied to the in-tube solid-phase microextraction (SPME) for online coupling with high-performance liquid chromatography (HPLC) to the direct determination of five estrogens in human urine samples. The NH2-MIL-53(Al)-polymer monolith was suitable for in-tube SPME owing to its good permeability, high extraction efficiency, chemical stability, good reproducibility and long lifetime. The extraction conditions including extraction solvent, pH of sample solution, flow rate of extraction and desorption, and desorption volume were investigated. Under the optimum conditions, the enrichment factors were 180–304 and saturated amounts of extraction were 2326–21393 pmol for estriol, 17β-estradiol, estrone, ethinyl estradiol and progesterone, respectively. The adsorption mechanism was also explored which contributed to its strong extraction to target compounds. The proposed method had low limit of detection (2.0–40ng/L) and good linearity (with R2 between 0.9908 and 0.9978). Four endogenous estrogens were detected in urine samples and the recoveries of all five analytes were ranged from 75.1–120% with relative standard deviations (RSDs) less than 8.7%. The results showed that the proposed online SPME-HPLC method based on NH2-MIL-53(Al)-polymer monolithic column was highly sensitive for directly monitoring trace amount of estrogens in human urine sample.

PEEK tube-based online solid-phase microextraction-high-performance liquid chromatography for the determination of yohimbine in rat plasma and its application in pharmacokinetics study.

Yohimbine is a novel compound for the treatment of erectile dysfunction derived from natural products, and pharmacokinetic study is important for its further development as a new medicine. In this work, we developed a novel PEEK tube-based solid-phase microextraction (SPME)-HPLC method for analysis of yohimbine in plasma and further for pharmacokinetic study. Poly (AA-EGDMA) was synthesized inside a PEEK tube as the sorbent for microextraction of yohimbine, and parameters that could influence extraction efficiency were systematically investigated. Under optimum conditions, the PEEK tube-based SPME method exhibits excellent enrichment efficiency towards yohimbine. By using berberine as internal standard, an online SPME-HPLC method was developed for analysis of yohimbine in human plasma sample. The method has wide linear range (2-1000 ng/mL) with an R2 of 0.9962; the limit of detection was determined and was as low as 0.1 ng/mL using UV detection. Finally, a pharmacokinetic study of yohimbine was carried out by the online SPME-HPLC method and the results have been compared with those of reported methods.

Development of a cheap and accessible carbon fibers-in-poly(ether ether ketone) tube with high stability for online in-tube solid-phase microextraction

Carbon fibers (CFs) are one kind of important industrial materials that can be obtained commercially at low price. Based on the high extraction efficiency of carbon sorbents, a cheap and accessible carbon fibers-in-poly(ether ether ketone) (PEEK) tube was developed for online in-tube solid-phase microextraction (SPME) method. Coupled to high performance liquid chromatography (HPLC), the CFs-in-tube SPME was applied to analyze eight polycyclic aromatic hydrocarbons (PAHs) in environmental aqueous samples. Extraction conditions (sampling rate, extraction time, methanol content) and desorption time were investigated for optimization of conditions. Under the optimum conditions, the CFs-in-tube SPME-HPLC method provided high extraction efficiency with enrichment factors up to 1748. Good linearity (0.05–50μgL−1, 0.5–50μgL−1) and low detection limits (0.01–0.1μgL−1) were also obtained. The online analysis method was finally applied to determine several model PAHs analytes in real environmental aqueous samples. Some target analytes were detected and relative recoveries were in the range of 92.3–111%. Due to natural chemical stability of carbon fibers and PEEK tube, the CFs-in-tube device exhibited high resistance to organic solvent, acid and alkaline conditions.

In vitro study of the binding between chlorpyrfos and sex hormones using headspace solid-phase microextraction combined with high-performance liquid chromatography: A new aspect of pesticides and breast cancer risk.

Endocrine-disrupting chemicals are compounds that alter the normal functioning of the endocrine system. Organophosphorus insecticides, as chlorpyrifos (CPS), receive an increasing consideration as potential endocrine disrupters. Physiological estrogens, including estrone (E1), 17β-estradiol (E2), and diethylstilbestrol (DES) fluctuate with life stage, suggesting specific roles for them in biological and disease processes. There has been great interest in whether certain organophosphorus pesticides can affect the risk of breast cancer. An understanding of the interaction processes is the key to describe the fate of CPS in biological media. The objectives of this study were to evaluate total, bound, and freely dissolved amount of CPS in the presence of three estrogenic sex hormones (ESHs). In vitro experiments were conducted utilizing a headspace solid phase microextraction (HS-SPME) combined with high-performance liquid chromatography (HPLC) method. The obtained Scatchard plot based on the proposed SPME-HPLC method was employed to determine CPS-ESHs binding constant and the number of binding sites as well as binding percentage of each hormone to CPS. The number of binding sites per studied hormone molecule was 1.10, 1, and 0.81 for E1, E2, and DES, respectively. The obtained results confirmed that CPS bound to one class of binding sites on sex hormones.

Determination of polycyclic aromatic hydrocarbons by solid-phase microextraction coupled to HPLC using a fiber with mesoporous silica coating

A novel SPME-HPLC method was developed for the determination of trace amounts of polycyclic aromatic hydrocarbons (PAHs). It was found that the SPME device with C8H17-SBA-15 (C8-SBA-15) mesoporous silica coating had high extraction efficiency, sufficient chemical and hydrothermal stability and good reversibility. The determination conditions for environmental pollutants like PAHs including extraction and desorption time, extraction temperature, ionic strength and stirring rate were optimized. Under optimized experimental conditions, results with good accuracy (with a recovery of 97.5–101.7%), precision (with a standard deviation of 0.15–1.07%) and low detection limit (LOD, 0.05–0.25 μg/L) were obtained, suggesting the SPME devices using chemical modified SBA-15 as coating material are promising in preconcentration, separation and determination of interested analytes in the future.