Application of dexmedetomidine for lung injury in elderly patients undergoing one-lung ventilation.

Introduction: This study aimed to evaluate the effects of dexmedetomidine (DEX) on lung injury, the oxygenation index and perioperative pulmonary complications in elderly patients who underwent thoracotomy with one-lung ventilation (OLV). Material and methods: A total of 120 elderly patients with lung cancer were included in the present study. According to the random number table method, these patients were randomly divided into two groups: group D and group C. Patients in group D were intravenously pumped with 0.5 µg/kg/h of DEX before anesthesia. The infusion was completed within 15 min, and anesthesia was induced by venous injection. Patients in group C were pumped with equal volumes of normal saline. Results: At T2 and T3, compared with group C, group D had a significant decrease in cardiac index, mean arterial pressure and central venous pressure (p < 0.05). At T2, T3 and T4, compared with group C, group D had a significant increase in pH and PaO2 (p < 0.05). At T2, T3 and T4, compared with group C, group D had a significant decrease in Qs/Qt (p < 0.05). At T6, compared with group C, group D had a significant decrease in the supernatant of bronchoalveolar lavage fluid of tumor necrosis factor-α and interleukin 6 (p < 0.05). At T5, compared with group C, group D had a significant decrease in Visual Analogue Scale score (p < 0.05), and a significant increase in Ramsay Sedation Scale score (p < 0.05), and the number of respiratory and cardiovascular events also decreased (p < 0.05). Conclusions: In elderly patients, dexmedetomidine can reduce Qs/Qt and increase PaO2 during OLV in surgery. It can reduce lung injury. Moreover, DEX reduced respiratory and cardiovascular complications in the perioperative period.

Clinical therapeutic effects of eradication of Helicobacter pylori in treating patients with type 2 diabetes mellitus: A protocol for systematic review and meta-analysis.

BACKGROUND: Previous studies have demonstrated that Helicobacter pylori is a critical factor in the development of gastrointestinal diseases. However, only limited studies have reported results on the relationship between H pylori infection and patients with type 2 diabetes mellitus (T2DM). Moreover, the conclusions from these past studies are variable. Because there are contradictory results on this issue, the present study aims to examine the clinical therapeutic impacts of H pylori eradication to treat patients experiencing T2DM. METHODS: The present protocol is drafted according to the provisions of the Preferred Reporting Items for Systematic Review and Meta-analyses Protocols guidelines. PubMed, Cochrane Central Register of Controlled Trials databases, EMBASE, Web of Science, China National Knowledge Infrastructure, and Chinese BioMedical Literature Database will be searched up to May 2021 to obtain randomized controlled trials evaluating the clinical therapeutic effects of H pylori eradication to treat patients experiencing T2DM. We will use 2 investigators independently to carry out study selection, data extraction, and employ the Cochrane Collaboration criteria to evaluate their risks of bias. Furthermore, we will apply Stata 16.0 software to perform data analysis. RESULTS: We intend to evaluate the clinical therapeutic impacts of H pylori eradication to treat patients suffering from T2DM. CONCLUSIONS: Our findings may support existing evidence on the clinical therapeutic impacts of H pylori eradication to treat patients with T2DM. ETHICS AND DISSEMINATION: Since all data will be extracted from the published literature, the study does not require an ethical approval. OSF REGISTRATION NUMBER: May 31, 2021.osf.io/qtexu. (https://osf.io/qtexu/).

Ventilation with a low tidal volume vs. an intermediate tidal volume during pleural decortication.

OBJECTIVE: This study aims to evaluate the effects of low tidal volume and positive end expiratory pressure (PEEP) combined with pressure-controlled ventilation-volume guaranteed (PCV-VG) ventilation on one lung ventilation (OLV) in patients with tuberculous destroyed lung (TDL). METHODS: Patients of two groups were all treated with volume controlled ventilation (VCV) on two-lung ventilation, and the tidal volume was set to 8 ml/kg according to standard body weight, breath rate was set to 10-14 times/min, inspiration and expiration ratio was set to 1:1.5. During OLV, VCV was used in group C, and the tidal volume was set to 8 ml/kg; PCV-VG was given to group P patients, and the tidal volume was set to 6 ml/kg, followed by PEEP at 7 cm H2O. Breath rate was set to 12-16 times/min, and inspiration and expiration ratio was set to 1:1.5 in both groups on OLV. RESULTS: Pplat, Ppeak and intrapulmonary shunt (Qs/Qt) were lower at T2 and T3 in group P, when compared to group C (P<0.05). At T2, T3 and T4, the oxygenation index (OI) increased, Qs/Qt decreased and arterial carbon dioxide partial pressure (PaCO2) increased in group P (P<0.05). At T5, the concentration of IL-6, TNF-α and BNP decreased in group P. CONCLUSION: Low tidal volume and PEEP combined with PCV-VG ventilation might be helpful for alleviating pulmonary injury in OLV, and reducing airway pressure and Qs/Qt during OLV in surgery. KEY WORDS: Destroyed lung, Low tidal volume, Low tidal volume, Positive end-expiratory pressure, Pressure-controlled ventilation, One lung ventilation.

Ventilation with a low tidal volume vs. an intermediate tidal volume during pleural decortication.

OBJECTIVE: This study aims to evaluate the effects of low tidal volume and positive end expiratory pressure (PEEP) combined with pressure-controlled ventilation-volume guaranteed (PCV-VG) ventilation on one lung ventilation (OLV) in patients with tuberculous destroyed lung (TDL). METHODS: Patients of two groups were all treated with volume controlled ventilation (VCV) on two-lung ventilation, and the tidal volume was set to 8 ml/kg according to standard body weight, breath rate was set to 10-14 times/min, inspiration and expiration ratio was set to 1:1.5. During OLV, VCV was used in group C, and the tidal volume was set to 8 ml/kg; PCV-VG was given to group P patients, and the tidal volume was set to 6 ml/kg, followed by PEEP at 7 cm H2O. Breath rate was set to 12-16 times/min, and inspiration and expiration ratio was set to 1:1.5 in both groups on OLV. RESULTS: Pplat, Ppeak and intrapulmonary shunt (Qs/Qt) were lower at T2 and T3 in group P, when compared to group C (P<0.05). At T2, T3 and T4, the oxygenation index (OI) increased, Qs/Qt decreased and arterial carbon dioxide partial pressure (PaCO2) increased in group P (P<0.05). At T5, the concentration of IL-6, TNF-α and BNP decreased in group P. CONCLUSION: Low tidal volume and PEEP combined with PCV-VG ventilation might be helpful for alleviating pulmonary injury in OLV, and reducing airway pressure and Qs/Qt during OLV in surgery. KEY WORDS: Destroyed lung, Low tidal volume, Low tidal volume, Positive end-expiratory pressure, Pressure-controlled ventilation, One lung ventilation.

Chiral stationary phase based on cellulose derivative coated polymer microspheres and its separation performance.

Chiral stationary phases (CSPs) have always been research hotspot in enantiomer separation. Currently, most of the CSPs are based on silica platform. In this research, monodisperse, porous glycidyl methacrylate-divinylbenzene copolymer particles (poly(GMA-DVB)) were designed and prepared. Then the GMA was further reacted with ethylenediamine to introduce amino groups onto the polymer, which provide anchoring sites for cellulose derivatives. Herein, Cellulose-tris (3,5-dimethylphenylcarbamate) (CDMPC) was successfully coated onto the polymer microspheres, achieving a stable and successful CSP. The porous structure and the surface moieties of the CSPs were studied in detail. The chromatographic separation was optimized. Hexaconazole,methyl DL-mandelate,benzoin and tebuconazole have been successfully separated on the CSP column, with column efficiency as high as 10,200 plates/m, which is comparable with some silica-based CSPs. The research has indicated that the poly(GMA-DVB) is a promising candidate for constructing CSPs for chiral separation.

Fast separation of water-soluble vitamins by hydrophilic interaction liquid chromatography based on submicrometer flow-through silica microspheres.

In the present study, submicrometer flow-through silica microspheres (Sub-FTSiO2) was for the first time obtained via a suspension polymerization method coupled with sol-gel transition and phase separation. The Sub-FTSiO2 was characteristic of rich mesopores, penetrable macropores and small particle size, which would be beneficial to fast mass transfer, low column backpressure and high column efficiency. It was directly used as the hydrophilic interaction liquid chromatographic (HILIC) stationary phase, and the fast separation of seven water-soluble vitamins in 2.2 min was realized. The proposed method was successfully applied to the determination of water-soluble vitamins in two functional beverages on the market. The prepared Sub-FTSiO2 was well demonstrated for fast HILIC, and would be potential as the stationary phase matrix for fast liquid chromatography in diverse separation modes.

Application of alveolar recruitment strategy and positive end-expiratory pressure combined with autoflow in the one-lung ventilation during thoracic surgery in obese patients.

BACKGROUND: The present study aims to evaluate the influence of alveolar recruitment strategy (ARS) and positive end-expiratory pressure (PEEP) combined with autoflow on respiratory mechanics, the oxygen index (OI), pulmonary shut [Qs/Qt(%)], and the concentrations of IL-6 and TNF-α in venous blood after surgery in obese patients who experienced thoracic surgery with one-lung ventilation (OLV). METHODS: A total of 36 obese patients with ASAII-III degree, who experienced selective pulmonary lobectomy, were within 36-74 years old, and had a BMI of 30-40 kg/m2, were randomly divided into two groups: control group (C group) and protective ventilation group (P group). In the P group, ARS was given once when OLV began. Then, ventilation at 7 mmHg of PEEP and autoflow were given. The Ppeak before OLV (T1), at 30 minutes after OLV (T2), and at the 5 minutes after two-lung ventilation (TLV) (T3), and the changes of Pplat and Cdyn were recorded. Then, arteriovenous blood was drawn at T1, T2, T3 and T4 (6 hours after the operation), blood-gas indicators, including SPO2, PaCO2 and PaO2, were measured, and the value of Qs/Qt(%) was calculated. Afterwards, venous blood was collected at T1 and T5 (18 hours after surgery), and the concentrations of IL-6 and TNF-α were detected. The clinical pulmonary infection score (CPIS) was determined at the first day and seventh day after the operation. RESULTS: In both groups, Cdyn and OI decreased, while Pplat, Ppeak and Qs/Qt(%) increased (P<0.05) at T2, when compared with those at T1. At T2 and T3, Pplat and Ppeak decreased (P<0.05) in the P group, when compared with the C group. At T2, T3 and T4, OI increased (P<0.05) in the P group, when compared with the C group. At T2, T3 and T4, PaCO2 and Qs/Qt(%) decreased in the P group, when compared with the C group. The concentrations of IL-6 and TNF-α decreased in the P group, when compared with the C group. CONCLUSIONS: The ventilation model of ARS and PEEP combined with autoflow can better reduce airway pressure and the production of injurious inflammatory cytokines in blood in obese patients. Furthermore, it can reduce Qs/Qt during and at 6 hours after thoracotomy, improve OI and maintain the acid-base balance of the internal environment, which may be applied in clinical work. This brings new enlightenment and needs to be clarified through further studies.

Waxberry-like hierarchically porous ethyl-bridged hybrid silica microsphere: A substrate for enzyme catalysis and high-performance liquid chromatography.

In this study, the ethyl-bridged hybrid silica microsphere with hierarchically meso-macroporous structure was initially synthesized through a method combining dispersion polymerization with sol-gel transition and phase separation. The flow-through macropores rendered the microsphere a rough surface like a waxberry, and thus the material was named as waxberry-like ethyl-bridged hybrid silica sphere (WEHS). WEHS was characteristic of appropriate alkali-stability, which was highly difficult for the pure silica. Additionally, WEHS possessed hierarchical meso- and macropores, which added additional value for faster mass transfer than the conventional fully porous silica materials. Taking the advantages of WEHS, it was successfully applied as the substrate to immobilize lipase; the prepared immobilized lipase exhibited high catalytic activity and favorable reusability under alkaline conditions, which was significant in pitch control of neutral-alkaline papermaking industry. Moreover, as the high-performance liquid chromatographic stationary phase matrix, WEHS made the separation under alkaline mobile phase into a reality for the silica-based materials. Besides, an ultra-fast and efficient separation in minutes was achieved with lower consumption of solvents and saving analytical time, which is highly desired in modern analysis. In general, WEHS was a novel and promising candidate in the myriads of silica-based materials.

A simple approach to prepare a sulfone-embedded stationary phase for HPLC.

In the present study, a polar-embedded reversed-phase liquid chromatographic stationary phase that contained internal sulfone groups was prepared. The synthesis involved the "thiol-ene" click chemistry between the vinyl functionalized silica and 1-octadecanethiol, followed by the oxidization of sulfide to sulfone groups. The resulting material simultaneously possessed the alkyl chain, i.e. C18, and the internal sulfone groups. Elemental analysis demonstrates that the element contents of the C18/sulfone silica were C 8.94%, H 1.87% and S 0.66%. Chromatographic evaluations indicate that the C18/sulfone stationary phase exhibited a little less retention than the C18/sulfide one. A comparable chromatographic performance of neutral analytes was obtained on these two columns, but much better chromatographic performance in the case of basic and acid analytes was obtained on C18/sulfone stationary phase with additional features such as lower silanol activity, better stability (stable working conditions of pH 1.0-10.0), and better compatibility with 100% aqueous mobile phases. The batch-to-batch reproducibility was acceptable (the RSDs of retention times for the probes were no higher than 1.73%), demonstrating the suitability of the applied synthetic strategy for the new stationary phase. The C18/sulfone is a promising polar-embedded RPLC stationary phase.

Flow-through silica: A potential matrix for fast chromatographic enantioseparation with high enantioselectivity.

The demand for fast chromatographic enantioseparation aroused the hot research in stationary phase matrix. In the present study, the flow-through silica, which is characterized by hierarchical pores of through pores in several hundred nanometer range and mesopores about 20nm, was attempted for fast enantioseparation. Thanks to the large surface area and full openness of the through pores, the flow-through silica had comparable cellulose derivative loading amount as the commercial wide-pore silica, which was impracticable for most of the core-shell particles and sub-2-µm fully porous silica. In addition, the backpressure was about two times lower in the case of the flow-through silica of the same particle size to the commercial wide-pore silica, due to the highly porous structure of the former. Another appreciated merit of the flow-through silica in small size (~2µm) was the less dependence of column efficiency on the flow rate. All of the above features rendered the flow-through silica a tremendous potential for fast enantioseparation with desired enantioselectivity, especially suitable for the polysaccharide chiral selector.

Penehyclidine ameliorates acute lung injury by inhibiting Toll-like receptor 2/4 expression and nuclear factor-κB activation.

The aim of the present study was to investigate the effect of penehyclidine (PHC) on endotoxin-induced acute lung injury (ALI), as well as to examine the mechanism underlying this effect. A total of 60 rats were randomly divided into five groups, including the control (saline), LPS and three LPS + PHC groups. ALI was induced in the rats by injection of 8 mg lipopolysaccharide (LPS)/kg body weight. The rats were then treated with or without PHC at 0.3, 1 or 3 mg/kg body weight 1 min following LPS injection. After 6 h, serum levels of tumor necrosis factor (TNF)-α and interleukin (IL)-6 were determined by ELISA. In addition, the mRNA expression levels of toll-like receptor (TLR)2 and TLR4 were examined by reverse transcription-quantitative polymerase chain reaction in the lung tissue samples, and nuclear factor (NF)-κB p65 protein expression levels were examined by western blot analysis. The results demonstrated that lung injury was ameliorated by treatment with PHC (1 and 3 mg/kg body weight) as compared with treatment with LPS alone. Injection of LPS significantly increased the mRNA expression levels of TLR2 and TLR4, as well as the protein expression levels of NF-κB p65 in the lung tissue samples. Serum levels of TNF-α and IL-6 were also upregulated by LPS injection. Treatment of the rats with PHC following LPS injection suppressed the LPS-induced increase in TLR2/4 mRNA and NF-κB p65 protein expression levels. PHC also inhibited the increase in TNF-α and IL-6 serum levels. In addition, PHC reduced LPS-induced ALI and decreased the serum levels of TNF-α and IL-6, possibly by downregulating TLR2/4 mRNA expression and inhibiting NF-κB activity, and consequently alleviating the inflammatory response.

A simple method for the synthesis of a polar-embedded and polar-endcapped reversed-phase chromatographic packing with low activity of residue silanols.

Octadecyl bonded silica (ODS) is the most popular packing for reversed-phase chromatography. However, it generally demonstrates bad resolution for polar analytes because of the residue silanols and its poor stability in aqueous mobile phase. To address the problem, a new reversed-phase packing containing both polar-embedded and polar-endcapped moieties was proposed. It was prepared by a very simple method, in which the epoxide addition reaction of 3-glycidoxypropyltrimethoxysilane with 1-octadecanethiol proceeded simultaneously with the reaction of silane coupling onto silica particles. By controlling the molecular ratio of 3-glycidoxypropyltrimethoxysilane to 1-octadecanethiol higher than 1.0 (1.56 for the present study), both polar-embedded and polar-endcapped moieties were achieved onto the packing. The performance of the packing was evaluated in detail. The results demonstrated that neutral, acidic and basic analytes were well separated on the packing. The column efficiency for phenanthrene was 34,200 theoretical plates per meter. In addition, four nucleotides can be separated in 100% phosphate buffered saline solution with good reproducibility, which indicates the packing has good stability in aqueous mobile phase. Amitriptyline, a typical basic analytes, was eluted out with relatively symmetric peak shape (asymmetry factor of 1.36), which implies that the packing has not suffered from the negative effect of residue silanols significantly. Good stability in buffer solution of pH ranging from 2.0 to 10.0 was also documented for the packing.

Novel mode of liquid-phase microextraction: A magnetic stirrer as the extractant phase holder.

In the present study, a novel configuration of liquid-phase microextraction was proposed, in which a magnetic stirrer with a groove was used as the extractant phase holder. It was termed as magnetic stirrer liquid-phase microextraction. In this way, the stability of the organic solvent was much improved under high stirring speed; the extraction efficiency was enhanced due to the enormously enlarged contact area between the organic solvent and aqueous phase. The extraction performance of the magnetic stirrer liquid-phase microextraction was studied using chlorobenzenes as the probe analytes. A wide linearity range (20 pg/mL to 200 ng/mL) with a satisfactory linearity coefficient (r(2) > 0.998) was obtained. Limits of detection ranged from 9.0 to 12.0 pg/mL. Good reproducibility was achieved with intra- and inter-day relative standard deviations <4.8%. The proposed magnetic stirrer liquid-phase microextraction was simple, environmentally friendly and efficient; compared to single-drop microextraction, it had obvious advantages in terms of reproducibility and extraction efficiency. It is a promising miniaturized liquid-phase technology for real applications.

Penetrable silica microspheres for immobilization of bovine serum albumin and their application to the study of the interaction between imatinib mesylate and protein by frontal affinity chromatography.

In the current study, novel featured silica, named penetrable silica, simultaneously containing macropores and mesopores, was immobilized with bovine serum albumin (BSA) via Schiff base method. The obtained BSA-SiO2 was employed as the high-performance liquid chromatographic (HPLC) stationary phase. Firstly, D- and L-tryptophan were used as probes to investigate the chiral separation ability of the BSA-SiO2 stationary phase. An excellent enantioseparation factor was obtained up to 4.3 with acceptable stability within at least 1 month. Next, the BSA-SiO2 stationary phase was applied to study the interaction between imatinib mesylate (IM) and BSA by frontal affinity chromatography. A single type of binding site was found for IM with the immobilized BSA, and the hydrogen-bonding and van der Waals interactions were expected to be contributing interactions based on the thermodynamic studies, and this was a spontaneous process. Compared to the traditional silica for HPLC stationary phase, the proposed penetrable silica microsphere possessed a larger capacity to bond more BSA, minimizing column overloading effects and enhancing enantioseparation ability. In addition, the lower running column back pressure and fast mass transfer were meaningful for the column stability and lifetime. It was a good substrate to immobilize biomolecules for fast chiral resolution and screening drug-protein interactions.

Nickel Oxide Nanoparticle-Deposited Silica Composite Solid-Phase Extraction for Benzimidazole Residue Analysis in Milk and Eggs by Liquid Chromatography-Mass Spectrometry.

A novel nickel oxide nanoparticle-deposited silica (SiO2@NiO) composite was prepared via liquid-phase deposition (LPD) and then employed as a solid-phase extraction (SPE) sorbent. When the SPE was coupled with liquid chromatography-electrospray ionization mass spectrometry (LC-ESI/MS) analysis, an analytical platform for the sensitive determination of benzimidazole residues in egg and milk was established. The limits of detection of nine benzimidazoles were in the range of 0.8-2.2 ng/mL in milk and 0.3-2.1 ng/g in eggs, respectively, which was 5-10 times superior to the methods with other adsorbents for SPE. The recoveries of nine benzimidazoles spiked in milk and egg ranged from 70.8 to 118.7%, with relative standard deviations (RSDs) being less than 18.9%. This work presented the excellent extraction performance of NiO on benzimidazoles for the first time, and the applicability of the LPD technique used as sorbents for trace analysis in complex matrices was also demonstrated.

Preparation, characterization and application of a reversed phase liquid chromatography/hydrophilic interaction chromatography mixed-mode C18-DTT stationary phase.

A mixed-mode chromatographic stationary phase, C18-DTT (dithiothreitol) silica (SiO2) was prepared through "thiol-ene" click chemistry. The obtained material was characterized by fourier transform infrared spectroscope, nitrogen adsorption analysis and contact angle analysis. Chromatographic performance of the C18-DTT was systemically evaluated by studying the effect of acetonitrile content, pH, buffer concentration of the mobile phase and column temperature. It was demonstrated that the novel stationary phase possessed reversed phase liquid chromatography (RPLC)/hydrophilic interaction liquid chromatography (HILIC) mixed-mode property. The stop-flow test revealed that C18-DTT exhibited excellent compatibility with 100% aqueous mobile phase. Additionally, the stability and column-to-column reproducibility of the C18-DTT material were satisfactory, with relative standard deviations of retention factor of the tested analytes (verapamil, fenbufen, guanine, tetrandrine and nicotinic acid) in the range of 1.82-3.72% and 0.85-1.93%, respectively. Finally, the application of C18-DTT column was demonstrated in the separation of non-steroidal anti-inflammatory drugs, aromatic carboxylic acids, alkaloids, nucleo-analytes and polycyclic aromatic hydrocarbons. It had great resolving power in the analysis of various compounds in HILIC and RPLC chromatographic conditions and was a promising RPLC/HILIC mixed-mode stationary phase.

A reversed-phase/hydrophilic interaction mixed-mode C18-Diol stationary phase for multiple applications.

A mixed-mode chromatographic packing material, C18 and diol groups modified silica (C18-Diol), was prepared with controllable hydrophobicity and hydrophilicity. It demonstrated excellent aqueous compatibility and stability in aqueous mobile phase; compared to the traditional C18 column, improved peak shape of basic analytes was also obtained. Additionally, it exhibited both reversed-phase liquid chromatographic (RPLC) and hydrophilic interaction chromatographic (HILIC) performance; the analyte separation scope was thus enlarged, demonstrated by simultaneous separation of twenty acids, bases and neutrals. More interestingly, a novel on-line two-dimensional liquid chromatography on the single column (2D-LC-1C) was established by modifying the high performance liquid chromatographic instrument only with the addition of an extra six-port two-position valve. The early co-eluted components of the extract of Lonicera japonica on the 1st-dimension (RPLC) were collected for the online re-injection to the 2nd-dimension (HILIC) by conveniently varying the mobile phase components. Six more peaks were obtained. The established system was simple, easy operation and low cost, which had advantages in analyzing complicated samples.

Magnetic nanoparticles with hydrophobicity and hydrophilicity for solid-phase extraction of polycyclic aromatic hydrocarbons from environmental water samples.

Magnetic nanoparticles (MNPs) featured with divinylbenzene (DVB) and sulfonate functionalities (Fe3O4-DVB-SO3(-)) were prepared via "thiol-ene" click chemistry. The hydrophobic DVB moieties were dedicated for extraction while the hydrophilic sulfonate groups were designed for dispersing the MNPs in aqueous sample solution. Thus, the specially designed material could ensure operational convenience and improve reproducibility during extraction. The application of the material was demonstrated by the extraction of polycyclic aromatic hydrocarbons (PAHs) from environmental water samples followed by gas chromatography-mass spectrometric analysis. The main factors influencing the extraction, including the type of the desorption solvent, the agitation mode, the amount of MNPs, extraction and desorption time and salt addition in sample solution, were investigated in detail. Under the optimized conditions, the proposed method showed satisfactory reproducibility with intra-day and inter-day relative standard deviations less than 16.5% and 21.2%, and low limits of detection of 1.1pgmL(-1), 0.8pgmL(-1), 1.1pgmL(-1), 1.4pgmL(-1), 0.6pgmL(-1), 2.1pgmL(-1) and 0.7pgmL(-1) for naphthalene, acenaphthene, fluorine, phenanthrene, anthracene, fluoranthene and pyrene, respectively. The developed method was also successfully used for determination of the PAHs in genuine lake and river environmental water samples by standard addition method. All the studied PAHs were detected in these waters with comparable results by the standard liquid-liquid extraction method. The developed MNPs with dual property of hydrophobicity and hydrophilicity were suitable for the treatment of water samples. The magnetic solid phase extraction based on this material was reliable and convenient. It has great potential in the preconcentration of trace analytes in complex matrix.

A novel two-dimensional liquid-chromatography method for online prediction of the toxicity of transformation products of benzophenones after water chlorination.

Benzophenone-type UV filters (BPs) are ubiquitous in the environment. Transformation products (TPs) of BPs with suspected toxicity are likely to be produced during disinfection of water by chlorination. To quickly predict the toxicity of TPs, in this study, a novel two-dimensional liquid-chromatography (2D-LC) method was established in which the objective of the first dimension was to separate the multiple components of the BPs sample after chlorination, using a reversed-phase liquid-chromatography mode. A biochromatographic system, i.e. bio-partitioning micellar chromatography with the polyoxyethylene (23) lauryl ether aqueous solution as the mobile phase, served as the second dimension to predict the toxicity of the fraction from the first dimension on the basis of the quantitative retention-activity relationships (QRARs) model. Six BPs, namely 2,4-dihydroxybenzophenone, oxybenzone, 4-hydroxybenzophenone, 2-hydroxy-4-methoxybenzophenone-5-sulfonic acid, 2,2'-dihydroxy-4,4'-dimethoxybenzophenone and 2,2'-dihydroxy-4-methoxybenzophenone, were the target analytes subjected to chlorination. The products of these BPs after chlorination were directly injected to the 2D-LC system for analysis. The results indicated that most TPs may be less toxic than their parent chemicals, but some may be more toxic, and that intestinal toxicity of TPs may be more obvious than blood toxicity. The proposed method is time-saving, high-throughput, and reliable, and has great potential for predicting toxicity or bioactivity of unknown and/or known components in a complex sample. Graphical Abstract The scheme for the 2D-LC online prediction of toxicity of the transformation products of benzophenone-type UV filters after chlorination.

Preparation and chromatographic evaluation of zwitterionic stationary phases with controllable ratio of positively and negatively charged groups.

The present study described the preparation and application of zwitterionic stationary phases (ACS) with controllable ratio of positively charged tertiary amine groups and negatively charged carboxyl groups. Various parameters, including water content, pH values and ionic strength of the mobile phase, were investigated to study the chromatographic characteristics of ACS columns. The prepared ACS columns demonstrated a mix-mode retention mechanism composed of surface adsorption, partitioning and electrostatic interactions. The elemental analysis of different batches of the ACS phases demonstrated good reproducibility of the preparation strategy. Additionally, various categories of compounds, including nucleosides, water-soluble vitamins, benzoic acid derivatives and basic compounds were successively employed to evaluate the separation selectivity of the prepared ACS stationary phases. These ACS phases exhibited entirely different selectivity and retention behavior from each other for various polar analytes, demonstrating the excellent application potential in the analysis of polar compounds in HILIC.