Solid-phase Extraction Research Articles

MCM-41 based dispersive micro-solid phase extraction of selected cephalosporin antibiotic residues from water samples prior to liquid chromatographic quantification

The occurrence of antibiotics in water bodies is of concern owing to the serious risk they pose to the environment, water security, aquatic organisms, and human health. In this study, mesoporous silica (MCM-41) nanostructured material was synthesised and characterized by various analytical techniques to determine its morphology and dimension, functional groups, surface charge, and textural properties. The nanostructured MCM-41 was used as an adsorbent in ultrasound-assisted dispersive micro solid-phase extraction (UA-D-µ-SPE) of cefadroxil (CFDX) and cephalexin (CPLX) in water samples. The concentration of the analytes in aqueous solution and real water samples was determined using high-performance liquid chromatography coupled with diode array detection (HPLC-DAD). The developed method for CFDX and CPLX in various water samples exhibited relative linear ranges of 0.1–600 µg/L and 0.1–550 µg/L, respectively, and correlation coefficients ranging from 0.9923–0.9993. Under optimum condition, the UA-D-µ-SPE/HPLC-DAD method displayed low limits of detection (LOD) and quantification (LOQ), with values ranging from 0.02–0.16 µg/L and 0.067–0.53 µg/L, respectively. The investigated intraday and interday accuracy in spiked water samples showed acceptable extraction efficiencies with a range of 73.5–98.1% and a relative standard deviation less than 6.0%. Moreover, the performance of MCM-41 was also assessed for the removal of cephalosporin antibiotics aqueous solutions. The kinetic and isotherm studies revealed that the adsorption process followed pseudo-second order and the Langmuir model, respectively. Furthermore, the maximum adsorption capacities for CFDX and CPLX were 43.2 and 47.8 mg/g. Lastly, the UA-D-µ-SPE/HPLC-DAD method was successfully applied in extracting, preconcentrating, separating and determining CFDX and CPLX in wastewater and surface water samples. These results demonstrated that MCM-41 can be applied in the removal of cephalosporin antibiotics from aquatic environments.

Optimization of a disposable pipette tips extraction (DPX) for the analysis of psychoactive substances in sweat specimens using Design of Experiments.

Novel psychoactive substances (NPS) continue to emerge in the marketplace and are often found as substances in traditional illicit drug materials, and users are often unaware of the presence of other drugs. The proper identification and confirmation of the exposure to a drug is made possible when a biological specimen is collected and tested. Sweat is an alternative biological matrix of great interest for clinical, and forensic analysis. One of the reasons is attributed to its expanded drug detection window, enabling a greater monitoring capacity, and provision of information on prospective drug use. However, the concentrations of drugs in sweat samples are often low, which requires highly sensitive and selective methods. Disposable pipette tips extraction (DPX) is a new miniaturized solid phase extraction technique capable of efficiently extracting analytes from biological specimens, providing high recoveries, and requiring minimized solvent use. This study describes the development and optimization of two methods for the extraction of basic and neutral psychoactive substances from sweat samples using GC-MS and Design of Experiments (DoE). The following extraction parameters were optimized by DoE techniques: sample volume, elution solvent volume, washing solvent volume, sample aspiration time, elution solvent aspiration time, and number of cycles performed, including the elution step. It was possible to design a simple extraction protocol that provided optimized recoveries for both basic and neutral compounds. The sum of analyte areas increased at a rate of 54.7% for compounds of basic character and 39.2% for compounds of neutral character. Therefore, our results were satisfactory, demonstrating that DPX can be successfully used for extracting the target drugs from sweat samples.

Engineered Mg-modified biochar-based sorbent for arsenic separation and pre-concentration

The utilization of biochar as a relatively efficient sorbent or stationary phase for the separation and preconcentration of a wide range of analytes represents an innovative approach in current sample pretreatment methods. Appropriate pre- and post-pyrolysis modification of the input precursor and pyrolysis product, respectively, allows targeted design of the physicochemical properties and sorption characteristics of the resulting sorbent. The present work deals with the preparation of pyrolysis materials based on unmodified cattail leaf biomass (BC) and its Mg-modified analogue (MgBC) by a slow pyrolysis process at 500 °C and a residence time of 1 h in a pyrolysis reactor. Physicochemical characterization of BC and MgBC carried out by pH, total C, N, surface size analysis (SSA), 13C NMR, SEM-EDX and XRD confirmed significant morphological and mineralogical differences between the prepared sorbents. By performing sorption experiments using a model anionic analyte (As) and application of Langmuir isotherm, we found that the predicted maximum sorption capacity of MgBC for As is 13.5-fold higher than that of BC. The sorption process of As by both sorbents is best described by the Sips adsorption isotherm (R2 ≥ 0.995) and a pseudo-nth order kinetic model (R2 ≥ 0.997). The optimum pH for As sorption by BC and MgBC sorbents is in the interval 5–6. The presence of competitive phosphate anions (equimolar concentration of 1:1) in the solution significantly reduces the sorption capacity of MgBC for As by 40% for BC by 70%. The presence of Cl- ions showed no significant effect on the sorption capacity of Bc and MgBC for As. Both sorbents were best recovered using 0.1 mol/L NaOH solution when the desorption efficiency for both sorbents was more than 95%. The MgBC sorbent showed 35% retention of As from the real sample in the model SPE column at a flow rate of 0.12 mL/s. Based on the obtained knowledge, it is evident that biochar-based sorbent prepared from Mg-modified precursor represents an effective sorbent for anionic forms of analytes and opens the possibility of its use also in preconcentration and separation techniques.

Porous Polymer Sorbents in Micro Solid Phase Extraction: Applications, Advantages, and Challenges.

In recent years, porous polymers have gained significant attention for their application as powerful and selective sorbents in micro solid phase extraction (µSPE). In this review we explore the preparation and utilization of various porous polymer sorbents, highlighting their impact on enhancing µSPE techniques. Molecularly imprinted polymers (MIPs), graphene oxide-modified frameworks, and zeolitic imidazole frameworks (ZIFs) are among the innovative materials discussed. These innovative materials have significantly improved µSPE methods, offering enhanced extraction efficiencies, superior selectivity, and reduced solvent consumption, all of which align with the principles of green chemistry. Key findings of this review include the demonstration that MIPs exhibit excellent target specificity, making them ideal for complex matrices, while graphene oxide frameworks and ZIFs provide increased surface area and stability for diverse analytical applications. Despite these advancements, challenges remain, particularly the high cost of certain innovative materials, limited reusability, and the absence of automation in µSPE workflows. Furthermore, controlling the precise synthesis and functionalization of these sorbents continues to be a limiting factor. To address these issues, future research should focus on developing cost-effectiveness methods, the use of biopolymer or sustainable feedstocks, and scalable synthesis methods; integrating automation into µSPE; and exploring new polymeric materials with enhanced properties. Additionally, novel hybrid materials that combine the strengths of multiple sorbents offer a promising direction for future exploration. We critically analyze the advantages and limitations of each sorbent type, providing a comprehensive overview of their applications in µSPE. This paper also examines the synthesis, characterization, and unique properties of these porous polymers, emphasizing their role in advancing analytical chemistry towards more efficient and environmentally friendly practices. The need for continued development of high-performance, low-cost, and sustainable sorbents is underscored to further enhance the effectiveness of µSPE techniques.

Simultaneous determination of nineteen azo dyes in water samples by gas chromatography-mass spectrometry after Fe3O4@COF based dispersive solid phase extraction

This study was performed for the determination of nineteen azo dyes at trace levels in stream water sample by gas chromatography-mass spectrometry (GC-MS). The selected analytes were preconcentrated with the help of dispersive solid phase extraction (DSPE). Fe3O4 magnetic nanoparticle was modified with covalent organic framework (COF) and the synthesized Fe3O4@COF nanocomposite was used as adsorbent for the separation of the analytes from aqueous solution. The synthesized Fe3O4@COF was introduced to the literature for the first time in this study. Five different parameters (pH, volume of buffer solution, volume of desorption solvent, mixing period and amount of adsorbent) were univariately optimized to acquire high extraction outputs for each analyte. Under the optimum Fe3O4@COF-DSPE-GC-MS conditions, limit of detection (LOD), limit of quantitation (LOQ), linear range (LR), coefficient of determination (R2) and percent relative standard deviation (%RSD) were calculated using external calibration plots belonging to each analyte. LOD values were found between 2.8 and 70.7 μg/kg with corresponding LOQ values ranging between 9.5 and 235.7 μg/kg. In addition, %RSD values were lower than 12.8%. Matrix matching calibration method was used in spiking experiments. Percent recovery results obtained for spiked stream water samples were between 83.1 and 122.4%, with %RSD ≤ 17.5. The high percent recoveries confirmed the accuracy and applicability of the developed Fe3O4@COF-DSPE-GC-MS method for stream water samples.

Solid phase extraction to measure B-vitamins in aquatic systems

Solid phase extraction to measure B-vitamins in aquatic systems

Synthesis of β-cyclodextrin magnetic-graphene-oxide pyrenyl (β-mGOP) gels for high-throughput enrichment and detection of various trace mycotoxins in food using UHPLC-cIMS

In this research, β-cyclodextrin magnetic-graphene-oxide pyrenyl gel composite (β-mGOP) was employed to remove trace mycotoxins from food products. The β-mGOP gels exhibited a three-dimensional macroporous structure that facilitated the rapid diffusion of target molecules into the nanoporous structure of the covalent organic frameworks embedded within the gel. The adsorption process of mycotoxins onto the β-mGOP gels conformed to the pseudo-second-order kinetics and the Freundlich adsorption model. These findings demonstrated exceptional rapid adsorption kinetics without pore collapse, making the material suitable as fillers for solid-phase extraction adsorbents. Additionally, a novel screening technique utilizing β-mGOP gels in conjunction with cyclic ion mobility mass spectrometry was developed to illustrate the efficacy of β-mGOP gels in capturing various trace substances in food and enhancing detection resolution. The versatile, uncomplicated, and scalable characteristics of β-mGOP gels indicate their promising potential for future applications in high-throughput analysis of trace contaminants in food.

Repurposing eggshell membrane, a natural food waste, for in-syringe membrane solid phase extraction: Mercury determination in water samples

A rapid, simple, and cost-effective method for the determination of mercury in water samples using an eggshell membrane (ESM) as a sorbent material in the in-syringe membrane solid-phase extraction (ISMSPE) technique has been developed. The utilization of ESM, a natural waste product and a cost-effective sorbent material for ISMSPE, presents a promising approach for the determination of mercury ions, Hg(II), in water samples prior to cold vapor AAS (CV-AAS) analysis. The selectivity study of ESM shows that ESM's adsorption performance for Hg(II) is the highest among other metals, by 44.2%. The optimization for Hg(II) preconcentration, which includes the choice of eluting reagent, concentration, and volume of the eluting reagent, the number of cycles of adsorption and desorption, and sample volume, is discussed in this study. The range of linearity of this method was 0.5–100 μg/L, with a preconcentration factor of 80. This method exhibited good sensitivity, with an LOD and LOQ of 0.44 μg/L and 1.32 μg/L, respectively. The precision and accuracy of the method were also satisfactory, as indicated by the recoveries for three real water samples in the range of 89.3–99.7% and RSD% (n = 3), ranging from 1.0 to 8.0%. These findings demonstrate that the developed method is reliable and performs well in determining Hg(II) ions in real water samples. This study has successfully demonstrated ESM's potential as a valuable material for the preconcentration of Hg(II), offering an environmentally friendly approach that promotes sustainability.

An orthogonal approach for analysis of underivatized steroid hormones using ultrahigh performance supercritical fluid chromatography-mass spectrometry (UHPSFC-MS).

The crucial role of steroid hormones in health and diseases merits their high-throughput, accurate and affordable measurements in biological specimens. Despite advances in analytical methods, sensing and quantifying steroid hormones remains challenging. Immunoassays offer excellent sensitivity but are inherently labour-intensive, costly, and prone to false positives. Mass spectrometry (MS) has been increasingly utilised, with the main hurdle being the isobaric tendencies of similar analytes, which complicates their separation and accurate quantification. This study compares ultrahigh-performance supercritical fluid chromatography separation (UHPSFC) and ultra-high-performance liquid chromatography (UHPLC) for MS detection. It optimises the column chemistry, temperature, and pressure to provide an operational protocol for the resolution and quantification of analytes. It presents the systematic characterisation of UHPSFC-MS performance by investigating spiked blood samples using Solid-Phase Extraction (SPE) and describes the matrix effects associated with MS measurements. Although both separation methods showed adequate resolution, specificity, and retention time, UHPSFC-MS was superior for five out of seven columns tested. With added high-throughput capacities, UHPSFC-MS, thus, offers an optimal solution for the analysis of steroid hormones for research, medical chemistry, and clinical diagnostics.

Optimization of the Combined Use of Z-Sep Plus and EMR-Lipid in QuEChERS Procedure for the Analysis of Eight Pesticides in Real Milk Samples

AbstractOne of the most applied procedures for the determination of trace analytes in complex matrices is QuEChERS (an acronym for Quick, Easy, Cheap, Effective, Rugged, and Safe). QuEChERS procedures include an extraction step followed by a dispersive solid-phase extraction (dSPE) for analytes cleaning-up from the matrix components. A challenging task in QuEChERS procedures is extracting and determining pesticides from samples of high fat such as milk samples. This challenge induced the innovation of new adsorbents for the clean-up step such as Z-Sep Plus® and EMR-Lipid® to enable removal of fatty matrix components without affecting the recovery of hydrophobic analytes. This work aims to apply experimental design to optimize the combined application of both QuEChERS clean-up adsorbents; Z-Sep Plus® and EMR-Lipid® in addition to other QuEChERS parameters in the determination of eight pesticides: hexachlorocyclohexane, dichlorodiphenyldichloroethane, dichlorodiphenyltrichloroethane, primiphos ethyl, diazinon, malathion, endrin, and dimethoate in milk matrix. This was augmented by optimization of GC–MS/MS and UPLC-MS/MS to detect and determine analytes in extracts. The experimental design of QuEChERS procedure enabled the optimization of Z-Sep Plus®- and EMR-Lipid®-added adsorbent amounts with other method parameters to enable the maximum recovery of analytes. Furthermore, the optimized methods enabled low detection limits of the studied pesticides within a short analysis time (28 min for GC and 12 min for LC methods, respectively). The procedure was validated according to European SANTE/11312/2021 Guideline. Quantitation limit ranged from 1.7 to 3.2 ng/mL for GC–MS/MS method and from 1.7 to 3 ng/mL for UPLC-MS/MS method. Greenness assessment of the methods followed four approaches indicating an excellent value of greenness for the proposed methods. Furthermore, 45 real milk samples collected from the Egyptian market were tested with the developed procedure for the presence of pesticides.

Pharmacokinetic-Pharmacodynamic Modeling of the Immune-Enhancing Effect of Shikimic Acid in Growing Pigs.

Shikimic acid (SA), extracted from the fruit of shikimi-no-ki, is used both as a preservative in the food industry and as an intermediate for a variety of active ingredients with a wide range of pharmacological functions. A deeper understanding of the pharmacokinetic process of SA in pigs and its impact on humoral immunity could prove invaluable in facilitating its clinical application in veterinary and human medicine. The pharmacokinetic study employed a two-period, two-sequence, crossover design to animal experiments and developed a novel method of pig plasma preparation using water as an extractant and ionization promoter, followed by purification and enrichment on a MAX solid phase extraction (SPE) column. The results showed that SA is rapidly absorbed after intragastric administration (50 mg/kg BW), reaching a plasma Cmax of 10,823.44 ng/mL at 1.78 h, followed by rapid elimination, with a t1/2 of 1.81 h, consistent with a one-compartment model. The results for intravenous administration (2 mg/kg BW) were consistent with a two-compartment open model with a t1/2 of 3.66 h, with concentrations below the limit of quantification (LOQ) observed beyond 12 h postdose. The absolute bioavailability of SA in pigs was calculated to be 21.68%. Furthermore, the Pearson's correlation analysis demonstrated a strong positive correlation between SA concentration in pig plasma and the changes of C3, C4 and IgG, IgA, and IgM (0.6 < R < 1, P < 0.0001). A more detailed pharmacokinetic-pharmacodynamic (PK-PD) modeling analysis of the intravenous group revealed the EC50/Cmax values of approximately 10%, with all γ values exceeding 3. This study was the inaugural investigation into the pharmacokinetics of SA in growing pigs, and it also revealed that SA has the potential to act as an immunopotentiator.

Ultra-Sensitive Quantification of Coproporphyrin-I and -III in Human Plasma Using Ultra-Performance Liquid Chromatography Coupled to Quadrupole Time-of-Flight Mass Spectrometry.

Organic anion transporting polypeptides (OATP) 1B1 and 1B3 are expressed in liver cells and are involved in drug uptake in the liver. OATP1B activity varies due to polymorphisms and is decreased by OATP1B inhibitors. Variability of OATP1B activity impacts the pharmacokinetics of OATP1B substrate drugs through drug-drug interactions. Lately, coproporphyrin-I (CP-I) and -III (CP-III) have been featured as quantitative endogenous biomarkers for evaluating the activity of OATP1B. CP-III has been reported to be transported not only by OATP1B but also by OATP2B1 in vitro. We have established a highly sensitive assay for the simultaneous measurement of CP-I and CP-III using a small volume of human plasma. The sample was pretreated by solid-phase extraction and analyzed by ultra-performance liquid chromatography coupled to quadrupole time-of-flight mass spectrometry (UPLC-QTOF/MS). This method that uses 100 μL of plasma met the acceptance criteria of the US Food and Drug Administration guidance for bioanalytical method validation, and the lower limit of quantification was 0.01 ng/mL for both coproporphyrins. The clinical application of the method was evaluated by measuring plasma CP-I and CP-III concentrations in healthy volunteers and rheumatoid arthritis (RA) patients. The measured concentrations were within the calibration range (0.01-50 ng/mL). Using this novel method to measure plasma concentrations of CP-I and CP-III may contribute to the evaluation of the activities of OATP1B1, OATP1B3, and OATB2B1 in healthy individuals and patients with various clinical conditions including RA.

Developing a novel pyridine-based ionic porous organic polymer with functional group for highly efficient extraction of phenolic endocrine disruptors in natural water and tilapia fish

A pyridine-based ionic porous organic polymer bearing hydroxyl groups (OH-iPOP) was developed for the first time by quaternization and crosslinking of 4-pyridinemethanol with 4,4′-bis(chloromethyl)biphenyl. OH-iPOP exhibited strong adsorption capacity for endocrine disruptors (EDs) including bisphenol A, bisphenol F, p-tert-butylphenol and bisphenol B (82.59–183.9 mg g−1), much higher than that of commercial adsorbents. The adsorption mechanism of OH-iPOP to EDs involved π-π⁎ interaction, hydrogen bond and electrostatic interaction. Using OH-iPOP as solid phase extraction adsorbent combined with high-performance liquid chromatography, a reliable method for the sensitive detection of trace EDs in natural water and tilapia fish was established. The detection limits (S/N = 3) were 0.01–0.04 ng mL−1 and 1.00–3.80 ng g−1 for natural water and tilapia fish, respectively. The method recoveries ranged from 81.5 % to 116 %. This work not only develops an efficient adsorbent for the enrichment of EDs, but also provides a new strategy for the synthesis of novel cationic POPs.

On-Site Sensitive Colorimetry for Free Cyanide by Using Ion-Pair Solid-Phase Extraction with Sedimentable Dispersed Particulates and Mobile Photography Box.

We propose a sensitive and simple colorimetric method using dispersed particle extraction for the highly sensitive detection of free cyanide in water samples. The method involves the direct capture of the color-producing compound by dispersed microparticles in a sample vessel containing colorimetric reagents and an adsorbent. The color of the microparticles that have naturally settled to the bottom of the microtube can be directly measured by visual observation or image analysis. A mobile photography box (MPB) suitable for use with a smartphone was developed to ensure reproducibility in the lighting environment during image acquisition. The MPB was then used to develop a highly sensitive analytical method for cyanide. This newly developed method allows direct measurement of the color tone of the target component collected on particles by irradiating light from below and photographing it perpendicularly. The method offers excellent portability, sensitivity, and reproducibility and is less affected by interfering color components. When applied to cyanide analysis, the detection limit reached 0.005 mg/L and measurements could be completed within 10 min, significantly shorter than the conventional absorbance spectrophotometric method, which requires 30 min. Thus, this method achieves highly sensitive cyanide analysis.

Optimization, Validation, and Application of Cleanup-Coupled Liquid Chromatography-Tandem Mass Spectrometry for the Simultaneous Analyses of 35 Mycotoxins and Their Derivatives in Cereals.

Mycotoxins occur singly or as co-contaminants and are primarily present in carbohydrate-rich foods such as cereals and cereal-based products. To effectively monitor mycotoxin co-contamination in cereals and cereal-based products, the simultaneous analysis of mycotoxins and their derivatives is required. Therefore, we coupled cleanup with LC-MS/MS for the rapid and robust quantitation of 35 analytes in wheat samples, including ergot alkaloids (EAs), which are rarely included in such analyses. To investigate the effects of different mycotoxin types on adsorbents, various dispersive solid-phase extraction sorbents were evaluated; a C18 end-capped sorbent exhibited the most effective cleanup performance. The method was validated by analyzing samples fortified with the mycotoxins at three concentration levels. The results exhibited high linearity, high recoveries, and repeatability. The methodology was applied for commercial cereal samples. The cereal samples were found to be 74% contaminated, and two samples measured levels of EAs at 609.63 μg/kg and 294.93 μg/kg, exceeding the limits defined by the EU for rye milling products. These findings highlight the validity of our novel method and the necessity of continuously monitoring mycotoxin levels in cereals to ensure food safety.

Optimization of pretreatment protocol for strontium-90 analysis in marine fish bone samples.

For systematic monitoring of radioactive nuclides in marine products, this study aimed at streamlining and simplifying the analysis method for the prominent radioisotope, strontium-90 (90Sr). The DGA chelate solid-phase extraction technique was employed for enhanced efficiency. The study focused on optimizing the necessary pretreatment procedures while minimizing the steps involving HNO3 leaching. This protocol enabled the quantitative recovery of strontium, and it facilitated a rapid analysis without the need for a time-consuming evaporation step and without waiting for secular equilibrium between 90Sr and its progeny to be reached. The method incorporating the optimized pretreatment protocol was applied to three diverse marine fish species and the accurate quantification of 90Sr at background levels in surface seawater was achieved. The method obtained concentrations in bone samples from these species that ranged from 0.036 to 0.120 mBq per kg-dry, and chemical yield values were notably high, ranging from 87.7% to 92.5%.

Study on the Determination of Polycyclic Aromatic Hydrocarbons (PAHs) in Fingernail and Hair Samples by Gas Chromatography Mass Spectrometry (GC/MS)

Information about human exposure to polycyclic aromatic hydrocarbons (PAHs) in Vietnam is still very limited. In this study, an accurate method for the determination of 16 PAHs in human hair and fingernail samples was developed. The nail and hair samples were digested in sodium hydroxide solution. PAHs in the digested solutions were extracted using organic solvents such as hexane and dichloromethane. The extracts were cleaned up by using solid phase extraction (SPE) cartridges containing silica gel with dichloromethane/hexane mixture as elution solvent. PAHs were quantified by a gas chromatography/mass spectrometry (GC/MS) system operated in electron impact ionization and selected ion monitoring (EI/SIM) mode. The liquid-liquid extraction and SPE clean-up steps were investigated to obtain acceptable recovery of PAHs before application to nail and hair samples. Recovery of PAHs in spiked nail and hair samples ranged from 66% to 112%, indicating acceptable method accuracy. Concentrations of 16 PAHs in the nail and hair samples were 160 and 733 ng/g, respectively. Major PAHs found in the nail and hair samples were naphthalene, phenanthrene, fluoranthene, and pyrene. Additional studies on human biomonitoring of PAHs and their related compounds should be conducted in Vietnam.

The role of hydroponic solution of Ulva fasciata in modulating the antibiotic resistance of Vibrio alginolyticus.

This study aimed to ascertain the active substances in the hydroponic solution of Ulva (U.) fasciata (HSUF) and their effects on antibiotics resistance of pathogenic bacteria Vibrio alginolyticus (Va.) at environmental levels. Analytical results of HSUF by solid-phase extraction and gas chromatography-mass spectrometry showed that HSUF contained rich active substances and dominated by 2,4,6-tribromophenol, acetal, mono (2-ethylhexyl) phthalate and 2- (4-hydroxybenzene) ethanol, etc. Thereinto, 2,4,6-tribromophenol had the lowest minimal inhibitory concentrations (MICs) of 64-128μg mL-1 for Va. strains. The rich antibacterial substances of HSUF inhibited 47%-63% of isolated Va. strains. After 20 generations of subculture for Va. strains in three dilutes (1/2 (HT), 1/20 (MT) and 1/50 (LT)) of HSUF (20g L-1), the resistance to streptomycin of Va. S1 and Va. M3 changed from intermediate resistance ability to susceptible level. The large promotion of reactive oxygen species was observed in different HSUF levels, but the biofilm formation of Va. S1 did not changed significantly. Transcriptome sequencing of Va. S1 demonstrated that antibiotic resistance gene lpxA was down-regulated at different HSUF levels. Live U. fasciata excreted a variety of active secondary metabolites (SMs) in HSUF, which exhibited strong inhibitory effects on three isolated Va. strains. HSUF changed the antibiotic resistance of Va. Strain, especially at a higher HSUF concentrations.

UHPLC-QTOFMS Urine Drug Screening With Dilute-and-Shoot Sample Preparation and Vacuum-Insulated Probe-Heated Electrospray Ionization.

We developed a method for comprehensive urine drug screening by applying dilute-and-shoot extraction and vacuum-insulated probe-heated electrospray ionization with ultra-high performance liquid chromatography high-resolution quadrupole time-of-flight mass spectrometry (DS-UHPLC-VIP-HESI-QTOFMS). The method involved five-fold post-hydrolysis dilution of urine samples and chromatography on a C18 UHPLC column prior to QTOFMS analysis. The recently introduced VIP-HESI ion source was chosen due to its enhanced ionization efficiency and compatibility with UHPLC-QTOFMS. Extensive data was acquired in positive ion mode with a low collision energy (7 eV) and an elevated collision energy (30 eV), using the broadband collision-induced dissociation data acquisition scan mode that continuously generated high-resolution and accurate mass for parent and fragment qualifier ions, and parent ion isotopic patterns. Compound identification was performed against an in-house database with 1263 compound entries, using an automated post-run reverse target database search with preset identification criteria. Method validation with 56 different drugs showed acceptable results for the limit of identification (median 5 ng/mL), matrix effects (70-130%), repeatability of retention times (< 1%), mass accuracy (< 1 mDa), as well as for specificity and stability. As compared with an established UHPLC-QTOFMS method relying on solid-phase extraction and conventional electrospray ionization, DS-UHPLC-VIP-HESI-QTOFMS produced comparable results from authentic clinical urine samples for most drugs, but showed clearly improved detectability for pregabalin, gabapentin, and ritalinic acid. We anticipate that the new method will be a step forward for laboratories performing routine urine drug screening due to its fast turnaround time, reduced manual workload, cost efficiency, and broad substance coverage.

Sustainability assessment in food analysis: the application of Green Analytical Chemistry tools to phthalate residue analysis in edible oils

Edible oils are essential in daily diet due to their high contribution of fatty acids, fat-soluble vitamins, and triglycerides. During the processes of growing, processing, storage, transport, or packaging, they can be contaminated by ubiquitous phthalate esters, considered endocrine disruptors. Thus, analytical methodologies to allow tight control of their presence are mandatory. Several sample treatments have been considered in this study: microwave-assisted extraction (MAE), liquid-liquid extraction (LLE), dispersive solid phase extraction (DSPE), magnetic SPE (MSPE), solid phase microextraction (SPME), Surface-enhanced Raman spectroscopy (SERS) or its combinations. However, the selection of an analytical procedure is usually performed from an Analytical Chemistry perspective, without considering factors such as the sustainability of the selected methodology and/or its impact on the environment. In this sense, the Green Analytical Chemistry strategy can play an important role. To demonstrate this fact, six different analytical procedures have been evaluated in terms of sustainability by using several greenness evaluation tools. Procedures from MAE-gel permeation chromatography (GPC)-SPE till SERS, showing adequate analytical characteristics, have been selected. The application of Analytical GREEnness calculator (AGREE), AGREE preparation (AGREE prep), and blue applicability grade index (BAGI) tools showed that MAE-GPC-SPE was the less green analytical procedure while SERS was the greener one. The BAGI evaluation showed that headspace (HS) and SERS were the most applicable procedures.