On-line Solid-phase Extraction Research Articles

A hybrid nano-MOF/polymer material for trace analysis of fluoroquinolones in complex matrices at microscale by on-line solid-phase extraction capillary electrophoresis

A hybrid material (nano-metal organic framework@organic polymer, named as nano-MOF@polymer) was applied for the first time as sorbent for on-line solid-phase extraction capillary electrophoresis with ultraviolet detection (SPE-CE-UV). The resulting material was prepared building layer-by-layer a HKUST-1 (Hong Kong University of Science and Technology-1) nano-MOF onto the polymer surface, which allowed controlling the thickness and maximizing the active surface area. The sorbent was widely characterized at micro- and nano-scale to validate the synthesis and to establish the material properties. Then, fritless microcartridges (2 mm) were assembled by packing only a few micrograms of sorbent particles and investigated for preconcentration of fluoroquinolones (FQs) in several real samples (river water, human urine and whole cow milk). Under the optimized conditions, the sample (ca. 60 μL) was loaded in separation background electrolyte (BGE, 50 mM phosphate (pH 7)), and retained analytes were eluted using a small volume of 2% v/v formic acid in methanol (ca. 50 nL). The SPE-CE-UV method was validated in terms of linearity, limit of detection (LOD), limit of quantification (LOQ), repeatability, reproducibility and reusability. The developed method showed a LOD decreasing until 1 ng L−1 when larger volumes of sample were loaded (ca. 180 μL), which was 500,000 times lower than by CE-UV. This undescribed sensitivity enhancement would arise from the homogenous and populated MOF nano-domains and the appropriate permeability of the hybrid material, which would promote high extraction efficiency and loading capacity. Furthermore, the sorbent showed appropriate selectivity regardless the analyzed complex environmental, biological or food matrix samples, achieving excellent detectability and recoveries (>90%).

Fast determination of vitamin A, vitamin D and vitamin E in food by online SPE combined with heart-cutting two dimensional Liquid Chromatography

An automatic method combing online solid phase extraction (SPE) and heart-cutting two dimensional Liquid Chromatography (2DLC) was developed for the simultaneous determination of vitamins A, vitamin D and four vitamins E homologues in foodstuff. In this method, the target analytes were released from their coated state of lipoprotein after saponification. Then the saponified solution was directly injected into the constructed system combining online SPE and heart-cutting 2DLC for enrichment, purification, separation and quantification. Online dilution was incorporated into the online SPE process to weaken the solvent effect on the first-column separation. The analysis of vitamins A and four E homologues were carried out by using PFP as the first column. The analysis of vitamin D was performed by using PAH as the second column. The results showed good linearity (R2>0.9999) of the analytes and good reproducibility (RSD < 2 %, n = 5). The limit of quantification of vitamin A, D2, D3 and α-, β-, γ-, δ-vitamin E (calculated by S/N = 10:1) were 0.030, 0.013, 0.014, 0.51, 0.33, 0.31 and 0.33 ng, respectively. The spiked recoveries ranged from 93.29 % to 103.66 %. The proposed method greatly simplifies the analytical workflow and improves the efficiency.

Strong links between load and manure and a comprehensive risk assessment of veterinary antibiotics with low KOW in intensive livestock farming watersheds

Various veterinary antibiotics (VAs) are used in large quantities as an essential component for intensive livestock farming, and can flow into the environment from various pollution sources. In this study, VAs in surface water and groundwater in the Gwangcheon stream watershed, an intensive livestock farming area in Korea, were analyzed using ultra-high-performance liquid chromatograph-quadrupole orbitrap high-resolution mass spectrometer with online solid phase extraction. Although the selected VAs are relatively mobile and have low KOW values it is significant to assess their fates and ecological risks in the environment. The concentration of VAs in the surface water was higher than that in groundwater by approximately 23-fold, indicating that the former were directly introduced from pollution sources such as livestock manure. An analysis of the correlation between livestock manure production and the residuals of VAs in the stream showed a high linearity (R2 > 0.70), confirming that livestock excreta significantly contributed to the VAs in the watershed. A combined evaluation of environmental behaviors and ecological risks of VAs was performed for the first time using persistence, bioaccumulation potential, and toxicity properties and risk quotient values of VAs. Trimethoprim showed persistence and a potential impact on the ecosystem. The cumulative risk quotient values at one sampling point exceeded 1 indicating that several VAs can cumulatively cause local risk. The risk assessment method considering pollution sources, different locations, and correlation analysis applied in this study will be useful in evaluating the impacts of trace pollutants in watersheds.

Alternative Routes for the Production of Natural 4-Vinylguaiacol from Sugar Beet Fiber Using Basidiomycetous Enzymes

Traditional smoking generates not only the impact flavor compound 4-vinylguaiacol, but concurrently many unwanted and potent toxic compounds such as polycyclic aromatic hydrocarbons. Enzyme technology provides a solution without any side-product formation. A feruloyl esterase from Rhizoctonia solani (RspCAE) liberated ferulic acid from low-priced sugar beet fiber. Decarboxylation of ferulic acid to 4-vinylguaiacol was achieved by a second enzyme from Schizophyllum commune (ScoFAD). Both enzymes were covalently immobilized on agarose to enable reusability in a fixed-bed approach. The two enzyme cascades showed high conversion rates with yields of 0.8 and 0.95, respectively, and retained activity for nearly 80 h of continuous operation. The overall productivity of the model process with bed volumes of 300 µL and a substrate flow rate of 0.25 mL min−1 was 3.98 mg 4-vinylguaiacol per hour. A cold online solid phase extraction using XAD4 was integrated into the bioprocess and provided high recovery rates during multiple elution steps. Attempting to facilitate the bioprocess, a fused gene coding for the two enzymes and a set of different linker lengths and properties was constructed and introduced into Komagataella phaffii. Longer and rigid linkers resulted in higher activity of the fusion protein with a maximum of 67 U L−1.

Simulation-Based Interpretation of Therapeutically Monitored Cabozantinib Plasma Concentration in Advanced Adrenocortical Carcinoma with Hemodialysis.

Adrenocortical carcinoma is an orphan but aggressive malignancy with limited treatment options. Cabozantinib (CAB), a tyrosine kinase inhibitor, has emerged as a new potential treatment. However, no data are available on whether and how CAB can be administered to patients undergoing hemodialysis. An liquid chromatography with tandem mass spectrometry detection method was developed and validated according to the European Medicines Agency and United States Food and Drug Administration guidelines for bioanalytical method validation. The samples were prepared using protein precipitation and online solid-phase extraction. The method was applied to clinical samples of an adrenocortical carcinoma patient receiving CAB treatment (80 mg daily). During the 10 days of observation, the patient received periodic hemodialysis on 7 days. Pharmacokinetic (PK) simulations were performed using Bayesian forecasting according to an existing population PK model for CAB. Based on the PK simulation, a mean plasma trough concentration of 1375 ng/mL [90% prediction interval (PI), 601-2602 ng/mL] in the steady state at a daily dose of 80 mg was expected for CAB. However, an individual simulation involving the measured plasma levels of the patient resulted in a mean trough concentration of 348 ng/mL (90% PI, 278-430 ng/mL). The model based on individual PK parameters estimated accessible plasma levels of 521, 625, and 834 ng/mL by dose adjustment to 100, 120, and 160 mg, respectively. After establishing an liquid chromatography with tandem mass spectrometry detection method for therapeutic drug monitoring of CAB, our analyses involving a single patient undergoing hemodialysis indicated that higher than expected doses of CAB were required to achieve reasonable plasma concentrations. Our study demonstrates the usefulness of therapeutic drug monitoring for the evaluation of "new" drugs in patients with renal impairment.

Evaluation of inhibitors of the arachidonic acid cascade with intact platelets using an on-line dilution and on-line solid phase extraction HPLC–MS method

An automatic on-line dilution/on-line solid phase extraction (SPE) system has been developed for the detection of metabolites of the arachidonic acid cascade in platelets. The method allows the direct injection of larger quantities of centrifugates from cell suspensions previously treated with an equal volume of an acetonitrile/methanol mixture for protein precipitation. The method was used to study the effect of inhibitors of platelet arachidonic acid cascade enzymes (cytosolic phospholipase A2α, cyclooxygenase-1, thromboxane synthase, 12-lipoxygenase) and related targets (cyclooxygenase-2, microsomal prostaglandin E synthase-1, 5-lipoxygenase) in intact platelets after stimulation with calcium ionophore A23187. In addition to enzyme inhibition, the cell-damaging properties of the test compounds was determined by measuring the release of serotonin from the platelets into the incubation buffer.

A cluster of tetrodotoxin poisoning in Oman

Introduction Tetrodotoxin (TTX) is a potent sodium channel blocker, with significant neurotoxicity, found in marine animals like pufferfish and blue-ringed octopus. The severity of toxicity depends on the amount of toxin ingested and the outcome depends on the time-lapse to appropriate medical care. Cases report We report five patients who presented with tetrodotoxin poisoning after consuming fried internal organs of local pufferfish from the coast of Oman. The patients’ clinical manifestations were consistent with the expected TTX toxidrome of perioral and generalized paresthesia, weakness of upper and lower extremities, gastrointestinal manifestations, dyspnea, dysarthria, ascending paralysis, hypotension, bradycardia and coma. The severity varied among the patients who recovered completely except one patient who developed a subarachnoid hemorrhage without underlying aneurysms on computed tomography-angiogram. This complication was potentially related to TTX poisoning and has not been previously reported. In addition to standard supportive management, patients with severe illness should potentially receive the intravenous acetylcholinesterase inhibitor neostigmine, and intermittent dialysis. Urine specimens were sent to CDC in Atlanta, where they were analyzed using online solid phase extraction (SPE) with LC-MS/MS and confirmed the diagnosis in all five cases. Discussion In general, the patients’ clinical manifestations were consistent with the expected TTX toxidrome except patient 3 who developed a subarachnoid hemorrhage early during his clinical course. Two patients received neostigmine and underwent dialysis with complete recovery.

A modified method of on-line solid phase extraction and fluorometric detection for underway monitoring and onboard analysis of trace ammonium in seawater

A sensitive and automated method for underway and onboard analysis of trace ammonium in seawater was established using on-line solid phase extraction and fluorescence detection. Ammonium reacted with o-phthalaldehyde and sulfite to produce isoindole derivative that was concentrated on a hydrophilic lipophilic balanced (HLB) cartridge and then rapidly eluted with ethanol and measured using a fluorescence detector. The work was modified from our previous developed method, where 30 mL of a seawater sample was introduced into a reaction bottle with a 10 mL pipette. In the modified method a 10 mL sample loop was adopted for sample introduction to reduce possible contamination caused by manual operation. More importantly, the present method makes underway monitoring much more automatic. The detection limit was 3.5 nmol L−1, and the relative standard deviation was 3.52% (n = 12) for a sample spiked with 40 nmol L−1 ammonium standard. The method was free of the effects of salinity, carry-over and dissolved organic matter, with recoveries between 94.0% and 106.1%. An equation was introduced to correct matrix effects, and pure water and seawater blank were found to be equivalent to ammonium concentration of 8.1 ± 2.2 nmol L−1 and 6.0 ± 0.8 nmol L−1, respectively. The correction method can also be introduced to determination of other trace analytes where matrix effect cannot be neglected. A technique of stopped-flow was adopted and stopped-flow time could be adjusted depending on the concentration of ammonium in the seawater samples. The sample throughput was 7–9 h−1, and the method permitted the analysis of samples over a wide range of concentrations. The modified method has been successfully applied for shipboard underway determination of ammonium in a coastal area and shipboard determination the ammonium concentration of discrete samples in three vertical profiles during a cruise in the South China Sea.

Automated separation and measurement of 226Ra and trace metals in freshwater, seawater and fracking water by online ion exchange chromatography coupled with ICP-MS

An online solid-phase extraction method combined with ICP-MS was developed to separate and quantify low levels of 226Ra and other metals in drinking water, lake, river and sea water, and fracking fluids. A dual-column lab-on-valve and multi-syringe flow injection analysis (LOV-MSFIA) system was developed to provide precise measurement of 226Ra in samples with total dissolved solids (TDS) less than 2%. For samples with higher levels of TDS (up to 20%), a triple-column LOV-MSFIA system was developed, which used AG 50 W-X8 cation exchange, Sr spec andNobias Chelate resins. Compared to earlier automated systems for Ra analysis, the dual and triple column systems described here were optimized to accommodate smaller sample volumes, more precise flow control and lower limits of detection (LOD). The LOV-MSFIA system coupled with ICP-MS is a significant improvement over traditional methods for low level 226Ra measurements, which require extended sample holding and/or analysis time. External calibration and standard addition were used to quantify the concentration of Ra for the LOV-MSFIA system. After method optimization, LODs for 226Ra as low as 4.3 mBq L−1 (1.75 fg L−1) were obtained in different sample matrices. The concentrations of selected metals were also measured on the triple-column system, together with Ra, with a total online processing time of 28.5 min per sample. Thus, the online LOV-MSFIA system is shown to be a powerful tool for the rapid analysis of low levels of 226Ra, as well as other metals, in various types of aqueous samples.

Determination of pharmaceuticals in solid samples in municipal wastewater treatment plants by online SPE LC-MS/MS using QuEChERS extraction.

In this study, a pretreatment method based on the QuEChERS method has been applied for simultaneously extracting 27 residual pharmaceuticals from wastewater solids. The extracted compounds have been analyzed using online solid-phase extraction (SPE) coupled to liquid chromatography with tandem mass spectrometry (LC-MS/MS). A recovery test was conducted according to the absorbent type, and buffers were added in the sample extraction step. The highest recovery efficiency could be observed when Na2SO4 was used as an absorbent and Na2EDTA was injected during the extraction process; the recovery efficiencies of the proposed method for the target compounds ranged from 61.3 to 137.2%, and the repeatability was 6.8%. These recovery and repeatability data showed that the proposed method could reliably analyze the 27 target residual pharmaceuticals. The concentrations of the target compounds were all below the limits of quantification: 830 ng g-1 for the target compounds in suspended solids, 2353 ng g-1 in activated sludge, and 1929 ng g-1 in waste sludge. The analytical method established in this study can be applied to quantify residual pharmaceuticals in solid samples and to investigate their behaviors in a municipal wastewater treatment plant.

Removal of low-calorie sweeteners at five Brazilian wastewater treatment plants and their occurrence in surface water

The consumption of low-calorie sweeteners (LCSs) such as acesulfame (ACE), sucralose (SUC), saccharin (SAC), cyclamate (CYC), aspartame (ASP), neotame (NEO), and stevioside (STV) is increasing worldwide to meet the demand for reduced-calorie foods and beverages. However, there are no consumption data available in Brazil, as well as their concentration in sewage and removal on wastewater treatment plants (WWTPs). In the present study, ACE, SUC, SAC, CYC, ASP, NEO, and STV were assessed at five WWTPs located in the metropolitan region of Campinas (São Paulo State, Brazil), in operation with different treatment processes. Surface water was also analyzed. Analyses were carried out by on-line solid-phase extraction ultra-high performance liquid chromatography-tandem mass spectrometry. The major points are the following: LCS concentrations in the influents ranged from 0.25 to 189 μg L−1 and followed the order CYC > ACE > SAC > SUC. NEO, ASP, and STV were not detected at any sampling site. Sweetener concentrations in the WWTP outputs differed mainly due to the different treatment setups employed. CYC and SAC were completely removed by biodegradation-based processes, while ACE removal was favored by the anaerobic-anoxic-aerobic process. SUC presented the highest concentration in the treated sewage, even at the WWTP operating with ultrafiltration membranes and therefore could be a marker compound for evaluation of the efficiency of removal of contaminants in WWTPs. Risk quotient estimation, using the PNEC and MEC values, indicated that the levels of the LCS reported here were harmless to the biota. The consumption of ACE, CYC, SAC, and SUC was estimated to be 2634 t year−1.

Boronic Acid-Functionalized Scholl-Coupling Mesoporous Polymers for Online Solid-Phase Extraction of Brassinosteroids from Plant-Derived Foodstuffs.

Brassinosteroids (BRs) are natural, nontoxic, non-hazardous, biosafe, and eco-friendly plant hormones, possessing diverse pharmacological activities. However, little is known about the type and content of BRs in frequently consumed plant-derived foodstuffs because of their low abundance and high abundance of interference. In this study, a selective, accurate, and sensitive method based on the online solid-phase extraction using the boronic acid-functionalized Scholl-coupling microporous polymer was developed for the analysis of BRs in plant-derived foodstuffs. Under optimum conditions, an excellent linearity (R2 ≥ 0.9970) and lower limits of detection (0.010-0.070 pg mL-1) were obtained. The high relative recoveries were in the range of 90.33-109.34% with relative standard deviations less than 9.73%. The method was successfully used for the determination of BRs in fifteen plant-derived foodstuffs. The present work offers a valuable tool for exploring BRs from the plant-derived foodstuffs and can provide useful information for developing functional foods.

High-Throughput Trace-Level Suspect Screening for Per- and Polyfluoroalkyl Substances in Environmental Waters by Peak-Focusing Online Solid Phase Extraction and High-Resolution Mass Spectrometry

Per- and polyfluoroalkyl substances (PFASs) occur widely in environmental waters. PFAS risk assessment necessitates the identification of unanticipated PFASs at trace levels and therefore requires ...

Determination of Polybrominated Diphenyl Ethers and Hydroxylated Analogues in Serum Using High Performance Liquid Chromatography-Inductively Coupled Plasma Mass Spectrometry with Online Solid Phase Extraction

Online solid phase extraction-high performance liquid chromatography-inductively coupled plasma mass spectrometry (Online SPE-HPLC-ICP-MS) technique was developed for simultaneous determination of 6 kinds of polybrominated diphenyl ethers and 5 kinds of hydroxyl metabolites in serum. A serum sample (200 μL) was directly analyzed after protein precipitation and dilution. The target analytes were automatically enriched on a solid phase extraction column, and then separated and analyzed by liquid chromatography-inductively coupled plasma mass spectrometry with methanol/acetonitrile/water as mobile phase. The main parameters such as loading rate, elution time and elution solvent were optimized. As a result, Oasis HLB was selected as the SPE column, the loading solvent was pure water at a rate of 3.0 mL/min, the elution solvent was methanol-acetonitrile-water (54:26:20, V/V), the elution flow rate was 1.0 mL/min, and the liquid chromatography column was ZORBAX Eclipse Plus C18. The limits of quantification (LOQ) of the method were 0.14–0.74 ng/L, the recoveries were 61.8%–77.7%, and the relative standard deviations (RSDs) of the results were 3.7%–10.1% (n = 3). The established method was successfully applied to the analysis of 30 serum samples. A total of 4 kinds of polybrominated diphenyl ethers and 2 kinds of hydroxy polybrominated diphenyl ethers were detected, and their occurrence characteristics were consistent with previous reports. The results showed that this method could be applied to analyze actual samples in large quantities, which was of great practical value.

A validated LC-MS/MS method for the quantification of climbazole metabolites in human urine

Climbazole is a preservative and an anti-dandruff ingredient with applications in various cosmetic products. The general population is therefore exposed to this chemical, and exposure monitoring is desirable. We have postulated a pathway for the human metabolism of climbazole, leading to two specific metabolites which can be excreted via urine. An analytical method for the determination of these metabolites in human urine was developed and validated. The sample preparation includes an enzymatic hydrolysis protocol. The measurement as such is based on online solid phase extraction (SPE), coupled to ultra-high-performance liquid chromatography-tandem mass spectrometry (UHPLC-MS/MS). Intra- and inter-series coefficients of variation (CV) were determined in the concentration range from 1 µg/l to 100 µg/l with spiked pooled urine samples, and they were consistently below 15%, mostly below 10%. The corresponding accuracies (mean relative recovery rates) in spiked pooled urine varied from 97% to 103%. The robustness of the method was estimated by spiking individual urine samples. At 1 µg/l, the robustness was rather limited due to interfering matrix peaks in several samples, but excellent results were obtained at 10 µg/l and 100 µg/l, with CVs between 7% and 14% and accuracies from 101% to 110%. Matrix interferences often seemed to be associated with higher creatinine contents (≥2.0 g/l) of the samples. We subsequently applied the method to urine specimens from a human metabolism study involving documented climbazole exposures. We were able to identify and quantify the postulated metabolites in those real samples, thus validating our metabolism hypothesis. We also investigated the precision and accuracy of the enzymatic deconjugation with the real samples. The deconjugation step was found to be highly repeatable and largely quantitative. Both metabolites formed glucuronides, though varying fractions were also excreted in unconjugated (free) forms. Phase II conjugates other than glucuronides did not seem to be produced in significant amounts. With our method, both climbazole metabolites can be reliably quantified in the range between about 1.5 µg/l (depending on matrix interferences in individual samples) and at least 500 µg/l.

Occurrence, spatiotemporal distribution, and risk assessment of current-use pesticides in surface water: A case study near Taihu Lake, China

This study involved the monitoring and risk assessment of current-use pesticides in surface water from the northwestern section of the Taihu Lake Basin (China) in 2019. In particular, 114 current-use pesticides were measured in samples collected during four campaigns spread across the wet, dry, and normal seasons. Pesticide concentrations were measured by means of a novel analytical method involving online solid-phase extraction coupled to LC-MS/MS. In total, 1 plant growth regulator, 34 herbicides, 23 insecticides, and 25 fungicides were detected. Detection frequencies greater than 90% were recorded for 26 pesticides; furthermore, acetamiprid, azoxystrobin, bentazone, carbendazim, isoprothiolane, metolachlor, paclobutrazol, and triadimenol were present in every sample. The measured pesticide concentrations varied widely, from below the detection limit to 10,600 ng/L (tricyclazole). The highest median concentrations for the fungicide, herbicide, and insecticide families were observed for carbendazim (135 ng/L), metolachlor (40 ng/L), and imidacloprid (31 ng/L), respectively. Twenty-two pesticides were quantitatively reported in Chinese surface water for the first time. The number and concentration of detected pesticides were significantly higher in June and September (wet season) compared to March and December (dry season). Agricultural areas of the study area were more contaminated than the residential and industrial sections. Imidacloprid was the only pesticide that exhibited high risk to sensitive ecological species (RQmedian > 1) in all four seasons. Isoproturon, isoprothiolane, and pretilachlor were identified as high risk in March (RQmedian = 4.5), September (1.3), and June (1.1), respectively; moreover, another eight pesticides posed a high ecological risk at specific sites. Seven pesticides recorded moderate risks (i.e., RQmedian = 0.1–1.0). Of the 18 pesticides with cases of high risk, a novel risk index, which accounted for frequency of PNEC exceedance, ranged from 6.7 (imidacloprid) to 7.1 × 10−5 (propiconazole). The integrated consideration of ecological risk and frequency of risk inform priorities for regional pesticide management and control.

Simultaneous enrichment of inorganic and organic species of lead and mercury in pg L−1 levels by solid phase extraction online combined with high performance liquid chromatography and inductively coupled plasma mass spectrometry

Quantification of ultra-trace inorganic and organic species of lead and mercury in unpolluted environmental water is crucial to estimate the mobility, toxicity and bioavailability and interactions. Simultaneous pre-concentration of Pb and Hg species in pg L−1 levels followed by multi-elemental speciation analysis makes great sense to a large set of unstable samples because of time advantages. Herein simultaneous enrichment and speciation analysis of ultra-trace lead and mercury in water was developed by online solid-phase extraction coupled with high performance liquid chromatography and inductively coupled plasma mass spectrometry (SPE-HPLC-ICP-MS) for this aim. Pb(II), trimethyl lead (TML), triethyl lead (TEL), Hg(II), methylmercury (MeHg) and ethylmercury (EtHg) were baseline separated in 11 min under gradient elution using 5 mM l-cysteine (Cys) at pH 2.5 in the 0–1 and 4–15 min and 5 mM Cys + 0.5 mM tetrabutyl ammonium hydroxide solution at pH 2.5 in the 1–4 min. Lead and mercury species in 10 mL intact water samples were adsorbed on a 1 cm C18 enrichment column pre-conditioned with 10 mL of 1 mM 2-mercaptoethanol at 10 mL min−1, and then directly desorbed by the mobile phases. High enrichment factors (459 for Pb(II), 1248 for TML, 1627 for TEL, 2485 for Hg(II), 1984 for MeHg and 1866 for EtHg) were obtained with good relative standard deviations (<5%), leading to low LODs (0.001–0.011 ng L−1) and LOQs (0.004–0.036 ng L−1). Good accuracy of this method was validated by two certified reference materials of total lead in water (GBW08601) and total mercury in water (GBW08603) along with spiked recoveries (89–93%). The method was applied to analyze trace lead and mercury species in river, lake, tap and rain water, and purified and mineral water. Inorganic lead of 13–68 ng L−1 and inorganic mercury of 21–49 ng L−1 were measured in the nine water samples whereas TML, TEL and MeHg were not detected with 2–5 ng L−1 EtHg presented only in one river water and tap water.

Development an automated and high-throughput analytical platform for screening 39 glucocorticoids in animal-derived food for doping control

For the purpose of doping control, increasing demand has been highlighted for the determination of glucocorticoids in animal derived foods. Although several methods have been established, the barrier of low throughput still exists for doping control. Herein, we report an on-line purification and high throughput platform for fast screening of 39 glucocorticoids in animal-derived food (pork, chicken, milk and eggs) using on-line solid-phase extraction (SPE) technology and liquid chromatography-tandem high-resolution mass spectrometry (LC-HRMS). An in-house developed, low-cost monolithic column was applied in this work which prevented the requirement of laborious and costly off-line solid-phase extraction columns. With one-step extraction and replacement of solvent, the sample can be directly and automatically injected as well as purified to screen 39 glucocorticoids in a single run time. The overall recoveries ranged from 62.0%–116.3% with intraday and inter-day relative standard deviation lower than 10.9% and 12.4%, respectively. The limits of quantitation for different matrices were between 0.84 and 4.94 μg/kg. Compared to the previous methods, the platform developed in this study shows excellent performance for rapid analysis of large numbers of samples and a wide variety of compounds with respect to short running time, analytical specificity and sensitivity as well as overall method accuracy and precision. In conclusion, this platform can function as a high-throughput tool in the field of doping analysis and contribute to a better safety assurance of animal-derived food.

Fabrication of nanomaterials incorporated polymeric monoliths and application in sample pretreatment

聚合物整体柱是由单体、交联剂、引发剂和致孔剂在模具中通过原位聚合而成的棒状整体。与传统的填充式固相萃取柱相比,聚合物整体柱吸附剂凭借制备简单、柱压低、传质快及pH使用范围宽泛等优点已广泛应用于食品分析、生物医药和环境卫生等领域的前处理中。然而,通常由于聚合方式难以控制,聚合物整体柱在制备过程中容易产生颗粒堆积、孔道不均匀从而导致孔隙率低和比表面积有限等问题。近年来,将纳米材料掺杂至聚合物整体柱以获得有序结构分布、良好吸附效率以及优越选择性能的新型吸附剂成为研究热点。纳米材料种类繁多,尺寸小,利用其表面丰富的活性基团、作用位点和超大的比表面积等优势,通过简单掺杂、共聚合和原位修饰等方法合成纳米掺杂聚合物整体柱,不仅能够改善其微观结构、柱床机械强度和稳定性,同时可以显著提高掺杂聚合物整体柱吸附剂的萃取性能和选择性。该文综述了碳材料、金属和金属氧化物、金属有机骨架、共价有机骨架和无机纳米粒子等不同纳米材料掺杂的聚合物整体柱、常用的构筑方法以及该类吸附剂在固相萃取、固相微萃取、搅拌棒吸附萃取和在线固相萃取等样品前处理领域的应用,并展望这一研究的发展趋势和应用前景,以期为前处理领域的研究提供参考。

Extraction and Separation of Chiral Amino Acids for Life Detection on Ocean Worlds Without Using Organic Solvents or Derivatization.

In situ instrumentation that can detect amino acids at parts-per-billion concentration levels and distinguish an enantiomeric excess of either d- or l-amino acids is vital for future robotic life-detection missions to promising targets in our solar system. In this article, a novel chiral amino acid analysis method is described, which reduces the risk of organic contamination and spurious signals from by-products by avoiding organic solvents and organic additives. Online solid-phase extraction, chiral liquid chromatography, and mass spectrometry were used for automated analysis of amino acids from solid and aqueous environmental samples. Carbonated water (pH ∼3, ∼5 wt % CO2 achieved at 6 MPa) was used as the extraction solvent for solid samples at 150°C and as the mobile phase at ambient temperature for chiral chromatographic separation. Of 18 enantiomeric amino acids, 5 enantiomeric pairs were separated with a chromatographic resolution >1.5 and 12 pairs with a resolution >0.7. The median lower limit of detection of amino acids was 2.5 μg/L, with the lowest experimentally verified as low as 0.25 μg/L. Samples from a geyser site (Great Fountain Geyser) and a geothermal spring site (Lemon Spring) in Yellowstone National Park were analyzed to demonstrate the viability of the method for future in situ missions to Ocean Worlds.