Separation and labeling are the crucial steps for the carbohydrates identification and detection in the important field of biochemistry, biomedicine, glycomics, and glycobiology. Herein, for the first time, a boronic acid decorated defective metal–organic framework (B-D-MI-100) nanoreactor is designed, which integrates fast separation and labeling of carbohydrates into one step. Without the sacrifice of internal room space, the incorporation of abundant functional boronic acid groups into the framework is achieved through metal–ligand–fragment coassembly strategy. And the novel solid phase orientation labeling approach performed within elaborate Cr based B-D-MIL-100 nanoreactor is facile to avoid the conformation transition of carbohydrates occurred in classical liquid-phase labeling. As a result, the novel approach presents several merits, including high separation efficiency (almost all of the incorporated boronic acid groups are available), much fast labeling reaction speed (labeling reaction time is decreased from 7 h to 3 min), high purity of the product, and three orders of magnitude lower applicable carbohydrate concentration for labeling. Thus, this new approach advances the idea to efficiently detect and identify trace carbohydrates in important fields such as glycomics and glycobiology.

Nanostructured materials have great potential for solid phase microextraction (SPME) on account of their tiny size, distinct architectures and superior physical and chemical properties. Herein, a core–shell TiO2@C fiber for SPME was successfully fabricated by the simple hydrothermal reaction of a titanium wire and subsequent amorphous carbon coating. The readily hydrothermal procedure afforded in situ synthesis of TiO2 nanowires on a titanium wire and provided a desirable substrate for further coating of amorphous carbon. Benefiting from the much larger surface area of subsequent TiO2 and good adsorption property of the amorphous carbon coating, the core–shell TiO2@C fiber was utilized for the SPME device for the first time and proved to have better performance in extraction of polycyclic aromatic hydrocarbons. In comparison to the polydimethylsiloxane (PDMS) and PDMS/divinylbenzene (DVB) fiber for commercial use, the TiO2@C fiber obtained gas chromatography responses 3–8 times higher than those obtained by the commercial 100 μm PDMS and 1–9 times higher than those obtained by the 65 μm PDMS/DVB fiber. Under the optimized extraction conditions, the low detection limits were obtained in the range of 0.4–7.1 ng L–1 with wider linearity in the range of 10–2000 ng L–1. Moreover, the fiber was successfully used for the determination of polycyclic aromatic hydrocarbons in Pearl River water, which demonstrated the applicability of the core–shell TiO2@C fiber.Keywords: core−shell; gas chromatography−mass spectrometry; high sensitivity; polycyclic aromatic hydrocarbons; solid phase microextraction;

Carbohydrates are known to be involved in a wide range of biological and pathological processes. However, due to the presence of multiple hydroxyl groups, carbohydrate recognition is a particular challenge. Herein, we reported an ultrasensitive solid-phase microextraction (SPME) probe based on phenylboronic acid (PBA) functionalized carbon nanotubes (CNTs) for direct in vitro or in vivo recognition of carbohydrates in biofluids as well as semi-solid biotissues. The coating of the proposed probe possessed a 3D interconnected porous architecture formed by the stacking of CNTs. As a result, the binding capacity toward carbohydrates was excellent. The proposed approach was demonstrated to be much superior to most carbohydrate sensors, including higher sensitivity, wider linear range, and excellent qualitative ability in multi-carbohydrate systems. Thus, this approach opens up new avenues for the facile and efficient recognition of carbohydrates for important applications such as glycomics.

A novel solid-phase microextraction (SPME) fiber was prepared by gluing poly(diallyldimethylammonium chloride) (PDDA) assembled graphene oxide (GO)-coated C18 composite particles (C18@GO@PDDA) onto a quartz fiber with polyaniline (PANI). The fiber surface coating was sequentially modified with bioinspired polynorepinephrine, which provided a smooth biointerface and makes the coating suitable for in vivo sampling. The novel custom-made coating was used to extract acidic pharmaceuticals, and high-performance liquid chromatography tandem mass spectrometry (HPLC-MS/MS) was employed for analysis. The custom-made coating exhibited a much higher extraction efficiency than the previously used commercial polydimethylsiloxane (PDMS) and polyacrylate (PA) coatings. The custom-made coating also possessed satisfactory stability (the relative standard deviations (RSDs) ranged from 1.60% to 10.3% for six sampling-desorption cycles), interfiber reproducibility (the RSDs ranged from 2.61% to 11.5%), and resistance to matrix effects. The custom-made fibers were used to monitor the presence of acid pharmaceuticals in dorsal-epaxial muscle of living fish, and satisfactory sensitivities (limits of detection ranged from 0.13 ng/g to 7.56 ng/g) were achieved. The accuracies were verified by the comparison with liquid extraction. Moreover, the novel fibers were successfully used to monitor the presence of acidic pharmaceuticals in living fish, which demonstrated that the custom-made fibers were feasible for possible long-term in vivo continuous pharmaceutical monitoring.

Solid-phase microextraction (SPME) kinetics in semisolid samples should be different from that in aqueous and gaseous samples, as convection is negligible in semisolid samples but dominates mass transfer in bulk phases of aqueous and gaseous samples. This study developed a mathematical model for describing SPME kinetics in semisolid samples by considering the diffusion of analytes in two compartments, i.e., the fiber coating and the ever-increasing diffusion domain in the sample matrix. The mathematical model predicted that SPME and the desorption of preloaded analytes from the fiber would be isotropic in semisolid samples, while SPME in semisolid samples would not follow the first order kinetics as in aqueous and gaseous samples. The predictions were proven true in the experiment of four pharmaceuticals in agarose gel. In return, it was observed in the experiment that SPME kinetics would deviate more significantly from the first order kinetics for the analytes with higher partition coefficients between the fiber and the sample matrix, which was well explained by the mathematical model developed in this study. In addition, SPME kinetics predicted by the model coincided well with the experimental results when the diffusion coefficients were at reasonable levels, which demonstrated that the model could be satisfactory for describing SPME kinetics in semisolid samples. The illustration of the nonfirst order SPME kinetics in semisolid samples can be valuable for evaluating the applicability of the existing pre-equilibrium calibration methods in semisolid samples.

•The mathematical expression of the lability factor of bound analyte was deduced.•Effective average diffusion coefficient was introduced.•The lability factors of PAHs in the diffusion boundary layers surrounding SPME fibers were estimated.•The lability factors of PAHs were successfully used to predict the mass transfer efficiencies of PAHs.Elucidating the availability of the bound analytes for the mass transfer through the diffusion boundary layers (DBLs) adjacent to passive samplers is important for understanding the passive sampling kinetics in complex samples, in which the lability factor of the bound analyte in the DBL is an important parameter. In this study, the mathematical expression of lability factor was deduced by assuming a pseudo-steady state during passive sampling, and the equation indicated that the lability factor was equal to the ratio of normalized concentration gradients between the bound and free analytes. Through the introduction of the mathematical expression of lability factor, the modified effective average diffusion coefficient was proven to be more suitable for describing the passive sampling kinetics in the presence of mobile binding matrixes. Thereafter, the lability factors of the bound polycyclic aromatic hydrocarbons (PAHs) with sodium dodecylsulphate (SDS) micelles as the binding matrixes were figured out according to the improved theory. The lability factors were observed to decrease with larger binding ratios and smaller micelle sizes, and were successfully used to predict the mass transfer efficiencies of PAHs through DBLs. This study would promote the understanding of the availability of bound analytes for passive sampling based on the theoretical improvements and experimental assessments.

•Magnetic mixed hemimicelles SPE was used for enrichment of illegal cationic dyes.•SDS-coated Fe3O4 nanoparticles were used for magnetic separation.•Cationic dyes were selectively enriched in acidic sample solution.•The main HPLC interferences, natural pigments, were eliminated.•The magnetic SPE was used for determination of illegal dyes in food matrices.In this study, mixed hemimicelles solid-phase extraction (MHSPE) based on sodium dodecyl sulfate (SDS) coated nano-magnets Fe3O4 was investigated as a novel method for the extraction and separation of four banned cationic dyes, Auramine O, Rhodamine B, Basic orange 21 and Basic orange 22, in condiments prior to HPLC detection. The main factors affecting the extraction of analysts, such as pH, surfactant and adsorbent concentrations and zeta potential were studied and optimized. Under optimized conditions, the proposed method was successful applied for the analysis of banned cationic dyes in food samples such as chili sauce, soybean paste and tomato sauce. Validation data showed the good recoveries in the range of 70.1–104.5%, with relative standard deviations less than 15%. The method limits of determination/quantification were in the range of 0.2–0.9 and 0.7–3 μg kg−1, respectively. The selective adsorption and enrichment of cationic dyes were achieved by the synergistic effects of hydrophobic interactions and electrostatic attraction between mixed hemimicelles and the cationic dyes, which also resulted in the removal of natural pigments interferences from sample extracts. When applied to real samples, RB was detected in several positive samples (chili powders) within the range from 0.042 to 0.177 mg kg−1. These results indicate that magnetic MHSPE is an efficient and selective sample preparation technique for the extraction of banned cationic dyes in a complex matrix.

•NH2-modified graphene fiber was prepared and characterized for the first time.•NH2-modified graphene fiber exhibited superior extraction performance.•The homemade fiber was evaluated by analyzing synthetic musks in water sample.In the current study, amino modified (NH2-modified) graphene was developed as a solid-phase microextraction (SPME) coating for the first time. The structure of the NH2-modified graphene was characterized by X-ray photoelectron spectroscopy (XPS) and transmission electron microscopy (TEM). The fiber was fabricated using xylene-diluted silicone sealant as an adhesion agent. The performance and feasibility of the NH2-modified graphene fiber was evaluated through autosampler-assisted direct immersion (DI) SPME followed by gas chromatography–mass spectrometry (GC/MS) for the analysis of five synthetic musks (muscone, galaxolide, musk-xylene, tonalide and musk-ketone) in aqueous samples. The results showed that the prepared fiber had good thermal stability, excellent solvent resistance and a long service lifetime (more than 200 replicate extraction cycles). The proposed autosampler-assisted DI-SPME-GC/MS method showed low limits of detection (0.46–5.96 ng L−1), wide linear ranges (5–500 ng L−1), and acceptable reproducibility (relative standard deviation, RSD < 12%). Finally, the method was successfully applied to the analysis of synthetic musks in environmental water samples with good recoveries (82.3–112%) and satisfactory precisions (RSD < 9.9%). These results indicated that the NH2-modified graphene provided a promising alternative in sample pretreatment.

•Sulfonated nanoparticles doped electrospun nanofibers were developed as SPME coating.•Polynorepinephrine was employed for the bioinspired sheath of electrospun nanofibers.•The fibers exhibited excellent extraction performance than the previously used fibers.•The fibers were successfully applied in in vivo sampling of pharmaceuticals in fish and vegetable.In this study, the biocompatible copolymer Poly(lactic acid-co-caprolactone) (PLCL) doped with sulfonated γ-Al2O3 nanoparticles was used for electrospun on stainless wires. The electrospun fibers were further sheathed by the self-polymerization of norepinephrine, a catecholamine found both in neurotransmitters and mussel adhesive proteins, to improve the surface hydrophilicity and provide a smooth bio-interface. The modified electrospun fibers on stainless wires were developed as novel custom-made solid-phase microextraction (SPME) fibers. These fibers exhibited much higher extraction efficiency compared to the polydimethylsiloxane (PDMS) fibers, especially to the sulfonamides. The custom-made SPME fibers also showed excellent stability with the relative standard deviations (RSDs) of intra-fiber ranged from 1.98% to 9.86% and RSDs of inter-fiber ranged from 4.36% to 15.6%. Moreover, these fibers were also demonstrated to be anti-biofouling and suitable for in vivo sampling. The custom-made SPME fibers were successfully applied to determine the Pharmaceutical concentrations in living fishes and vegetables. The accuracies were verified by the comparison with liquid extraction and the sensitivities were demonstrated to be satisfying with the limits of detection (LODs) ranged from 0.16 ng/g to 5.35 ng/g in fish muscle and 0.02 ng/g to 8.02 ng/g in vegetable stem.

•Hierarchical graphene was synthesized and characterized.•A high specific surface area of hierarchical graphene was achieved.•The highly sensitive SPME fiber was fabricated with hierarchical graphene.•The fiber was successfully applied to the analysis of OCPs in the river water.Graphene, a novel class of carbon nanostructures, has received great attention as sorbents due to its fascinating structures, ultrahigh specific surface area, and good extraction ability. In this paper, a new type of hierarchical graphene was synthesized through employing a mild and environment-friendly method. Such 3D interconnected graphene own a high specific surface area up to 524 m2 g−1, which is about 2.5 fold larger than the graphene, since the synthetic material has interlayer pores between nanosheets and in-plane pores. Then a superior solid-phase microextraction fiber was fabricated by sequentially coating the stainless steel fiber with silicone sealant film and hierarchical graphene powder. Since the novel hierarchical graphene possessed large surface area and good adsorption property, the as-prepared fiber exhibited good extraction properties of the organochlorine pesticides (OCPs). As for the analytical performance, the as-prepared fiber achieved low detection limits (0.08–0.80 ng L−1) and wide linearity (10–30,000 ng L−1) under the optimal conditions. The repeatability (n=5) for single fiber were between 5.1% and 11%, while the reproducibility (n=3) of fiber-to-fiber were range from 6.2% to14%. Moreover, the fiber was successfully applied to the analysis of OCPs in the Pearl River water.

•A HF-LPME coupled GC/MS was developed to determine OCPs in textiles.•The method exhibited good detect limits to OCPs.•The method was successfully applied to the analysis of OCPs in real textile samples.In this study, the hollow fiber-liquid phase microextraction (HF-LPME) coupled gas chromatograph/mass spectrometry (GC/MS) was firstly developed to determine 10 organochlorine pesticides (OCPs) in ecological textiles. The present method can offer high separation efficiencies with minimal sample and solvent consumption. The extraction conditions were optimized, including the types of hollow fiber and organic solvent, the extraction time, the stirring and the salinity. Under the optimized conditions, the linear ranges of OCPs in cotton, terylene and fur samples were 5–1000 ng/g, 10–1000 ng/g and 10–800 ng/g, respectively, and the detection limit of the three samples were 0.07–2.30 ng/g, 0.89–1.66 ng/g and 0.06–1.04 ng/g, respectively. The optimized method was then successfully used to determine the OCPs in 3 kinds of spiked real samples, including cotton, terylene and fur. The good recoveries and RSDs of the quantification in real textile samples were obtained and the results were confirmed by the traditional liquid extraction method (GB/T 18412-2006). This study proved that the HF-LPME method, which was simple, low-cost and virtually solvent-free, was reliable for the qualitative and quantitative analysis of the harmful OCP residues in ecological textiles.

Direct detection of fluoxetine and its metabolite norfluoxetine in living fish brains was realized for the first time by using a novel solid-phase microextraction fiber, which was prepared by mixing the polyelectrolyte in the oligomer of silicone rubber and followed by in-mold heat-curing. The polyelectrolyte was finally encased in microcapsules dispersed in the cured silicone rubber. The fiber exhibited excellent interfiber reproducibility (5.4–7.1%, n = 6), intrafiber reproducibility (3.7–4.6%, n = 6), and matrix effect-resistant capacity. Due to the capacity of simultaneously extracting the neutral and the protonated species of the analytes at physiological pH, the fiber exhibited high extraction efficiencies to fluoxetine and norfluoxetine. Besides, the effect of the salinity on the extraction performance and the competitive sorption between the analytes were also evaluated. Based on the small-sized custom-made fiber, the concentrations of fluoxetine and norfluoxetine in the brains of living fish, which were exposed to waterborne fluoxetine at an environmentally relevant concentration, were determined and found 4.4 to 9.2 and 5.0 to 9.2 times those in the dorsal-epaxial muscle. The fiber can be used to detect various protonated bioactive compounds in living animal tissues.

•A C18 composite SPME fiber was prepared with a new method.•A section of capillary column was used to ensure the constant of coating thickness.•The fiber exhibited excellent extraction performance to OCPs.•The fiber was successfully applied to the analysis of OCPs in real water samples.In this work, a C18 composite solid-phase microextraction (SPME) fiber was prepared with a new method and applied to the analysis of organochlorine pesticides (OCPs) in water sample. A stainless steel wire (o.d. 127 μm) was used as the substrate, and a mixture of the C18 particle (3.5 μm) and the 184 silicone was used as the coating material. During the process of fiber preparation, a section of capillary column was used to fix the mixture onto the stainless steel wire and to ensure the constant of coating thickness. The prepared fiber showed excellent thermal stability and solvent resistance. By coupling with gas chromatography–mass spectrometry (GC–MS), the fiber exhibited wide linearity (2–500 ng L−1) and good sensitivity for the determination of six OCPs in water samples, the OCPs tested included hexachlorobezene, trans-chlordane, cis-chlordane, o,p-DDT, p,p-DDT and mirex. Not only the extraction performance of the newly prepared fiber was more than seven times higher than those of commercial fibers, the limits of detections (LODs) (0.059–0.151 ng L−1) for OCPs achieved under optimized conditions were also lower than those of reported SPME methods. The fiber was successfully applied to the determination of OCPs in real water samples by using developed SPME–GC–MS method.

•HS-SPME–GC/MS method was developed to detect PAHs in leather products.•The method is simple and fast and avoids the use of large amount of organic solvent.•Low LOD, good reproducibility, wide linear rang and good recovery were achieved.•Home-made PDMS fiber significantly decreased the cost of sample analysis.The highlight of this work is that solid-phase microextraction (SPME) coupled with gas chromatography/mass spectrometry (GC/MS) was firstly introduced to the determination of the polycyclic aromatic hydrocarbons (PAHs) in leather products. In this work, a home-made poly(dimethylsiloxane) (PDMS) fiber was employed as the extraction phase to extract 9 sample PAHs in leather products by headspace SPME. Method development including the optimization of extraction, desorption process, and salt addition was done. The analytical figures of merit showed that the sampling linear ranges of the proposed method were 0.1–20 μg/L, and the detection limits of 9 PAHs were lower than 0.05 μg/L except chrysene with 0.12 μg/L. The developed method presented a simple, rapid, sensitive, and inexpensive method to detect PAHs in leather and was successfully applied to the detection of PAHs in three kinds of leather products. The spiked recoveries for 9 PAHs ranging from 81.7% to 124.9% also demonstrated the accuracy of the proposed method.

•Recent applications of SPME in plant analysis are summarized.•Characteristics of the applications are discussed.•Future development of SPME in plant analysis is prospected.As a very popular sample preparation technique, solid-phase microextraction (SPME) coupled with various analytical instrumentation, has been widely used for the determination of trace levels of different plant compounds, such as volatile organic compounds (VOCs) emitted from the different plant organs, and environmental contaminants in plants. In this review, recent applications of in vitro and in vivo SPME in plant analysis are discussed and summarized according to the different organs of plants, including fruits, flowers, leaves, stems, roots and seeds, and the whole plant as well. Future developments and applications of SPME in plant analysis, especially in vivo sampling approaches, are also prospected.

Vinyl-SBA-15 mesoporous organosilica was synthesized and used as coating material of solid-phase microextraction (SPME) by two coating techniques (direct coating and sol–gel). The synthesized vinyl-SBA-15 organosilica had highly ordered mesoporous structure, good thermal stability and a specific surface area of 688 m2 g−1. The fibers prepared by two methods were evaluated by the extraction of non-polar compounds (BTEX, benzene, toluene, ethylbenzene, o-xylene) and polar compounds (phenols). The results showed that the vinyl-SBA-15 fibers prepared by two methods exhibited high thermal stability (310 °C for direct-coated and 350 °C for sol–gel) and excellent solvent durability in methanol and acetonitrile. The fibers also presented much better extraction performance for both polar compounds (phenols) and non-polar compounds (BTEX), compared to commercial polydimethylsiloxane (PDMS) fiber, as well as wide linear ranges, low detection limits (0.008–0.047 μg L−1 for BTEX, sol–gel; 0.15–5.7 μg L−1 for phenols, direct-coated), good repeatabilities (RSDs less than 5.4% for BTEX) and satisfying reproducibilities between fibers (RSDs less than 5.8% for BTEX). The self-made fibers were successfully used for the analysis of BTEX and phenols in three aqueous samples including tap water, mineral water and lake water, which demonstrated the applicability of the vinyl-SBA-15 fibers.Highlights► Vinyl-SBA-15 mesoporous organosilica was synthesized and used as SPME fiber coating. ► The vinyl-SBA-15 fibers has high thermal stability and excellent solvent durability. ► The fibers showed better extraction performance than commercial fibers.

A novel carbon nanotube (CNT)-coated solid-phase microextraction fiber was prepared based on sol–gel technique. Commonly used fragile fused silica fiber was replaced with stainless steel wire, which made the fiber unbreakable. An approach was also proposed for batch producing, and good reproducibilities for fiber to fiber and between fibers were achieved. Experiments showed that the sol–gel-CNT fiber exhibited high thermal stability to resist 350 °C and excellent solvent durability in methanol and acetonitrile. Compared to commercial polydimethylsiloxane (PDMS) fiber, the sol–gel-CNT fiber represented significantly improved extraction efficiencies for both polar (phenols) and non-polar (benzene, toluene, ethylbenzene, and o-xylene) compounds. Meanwhile, no replacement effect, low carry-over and wide linear range demonstrated that the newly prepared sol–gel-CNT coating has liquid properties, which allow a relatively easy quantification procedure. Moreover, the characterization of the sol–gel-CNT coating was also evaluated with McReynold probe solutes. The results showed that the coating has better affinity for all the five types of solutes compared to commercial 7 μm PDMS fiber, which suggested that the coating has the potential to be developed as GC stationary phase.

Carbohydrates are known to be involved in a wide range of biological and pathological processes. However, due to the presence of multiple hydroxyl groups, carbohydrate recognition is a particular challenge. Herein, we reported an ultrasensitive solid-phase microextraction (SPME) probe based on phenylboronic acid (PBA) functionalized carbon nanotubes (CNTs) for direct in vitro or in vivo recognition of carbohydrates in biofluids as well as semi-solid biotissues. The coating of the proposed probe possessed a 3D interconnected porous architecture formed by the stacking of CNTs. As a result, the binding capacity toward carbohydrates was excellent. The proposed approach was demonstrated to be much superior to most carbohydrate sensors, including higher sensitivity, wider linear range, and excellent qualitative ability in multi-carbohydrate systems. Thus, this approach opens up new avenues for the facile and efficient recognition of carbohydrates for important applications such as glycomics.