Solid-phase Extraction Column Research Articles

Determination of Bovine Lactoferrin in Powdered Infant Formula and Adult Nutritionals by Heparin Affinity Extraction and Reverse-Phase High Performance Liquid Chromatography/Ultraviolet Detection (HPLC/UV): Single-Laboratory Validation, First Action 2021.10.

Infant formulas, pediatric and adult nutritional products are being fortified with bovine lactoferrin (bLF) due to its beneficial impacts on immune development and gut health. Lactoferrin supplementation into these products requires an analytical method to accurately quantify the concentrations of bLF to meet global regulatory and quality standards. To develop and validate a lactoferrin method capable of meeting the AOAC Standard Method Performance Requirements (SMPR requirements 2020.005). Powder formula samples are extracted using warm dibasic phosphate buffer, pH 8, then centrifuged at 4 °C to remove insoluble proteins, fat, and other solids. The soluble fraction is further purified on a HiTrap heparin solid-phase extraction column to isolate bLF from interferences. Samples are filtered, then analyzed by LC-UV using a protein BEH C4 analytical column and quantitated via external calibrant. The limit of quantitation (2 mg/100g), repeatability (2.0-4.8% RSD), recovery (92.1-97.7%) and analytical range (∼4-193 mg/100g) all meet the method requirements as stated in SMPR 2020.005 for lactoferrin. The reported single lab validation results demonstrate the ability of this lactoferrin method to meet or exceed the method performance requirements to measure soluble, intact, non-denatured bLF in infant and adult nutritional powder formulas. The use of a heparin affinity column to isolate lactoferrin from bovine milk products combined with a selective analytical chromatographic column provides suitable analyte specificity without requiring proprietary equipment or reagents.

Determination of 12 prohibited veterinary drug residues in pig urine by ultra high performance liquid chromatography-tandem mass spectrometry

A method was established for the simultaneous detection of 12 prohibited veterinary drugs, including β2-receptor agonists, nitrofuran metabolites, nitroimidazoles, chlorpromazine, and chloramphenicol, in pig urine. The sample was pretreated by enzymolysis, acid hydrolysis/derivatization, and liquid-liquid extraction combined with solid-phase extraction. Detection was performed using ultra high performance liquid chromatography-tandem mass spectrometry (UHPLC-MS/MS). Ammonium acetate solution (0.2 mol/L, 4.5 mL) and β-glucuronidase/aryl sulfatase (40 μL) were added to the sample, which was subsequently enzymolized at 37 ℃ for 2 h. Then, 1.5 mL of 1.0 mol/L hydrochloric acid solution and 100 μL of 0.1 mol/L o-nitrobenzaldehyde solution were added to the sample. The mixture was incubated at 37 ℃ for 16 h, and the analytes were extracted with 8 mL of ethyl acetate by liquid-liquid extraction. The lower aqueous phase obtained after extraction was extracted and purified using a mixed cation-exchange solid-phase extraction column. The extracts were combined, the extraction solution was blow-dried with nitrogen, and the residue was redissolved for determination. The samples were analyzed under multiple-reaction monitoring mode with both positive and negative electrospray ionization, and quantified using an isotope internal standard method. The correlation coefficients (r) of the 12 compounds were >0.99. The limits of detection (LODs) and quantification (LOQs) of chloramphenicol were 0.05 and 0.1 μg/L, respectively, and the LODs and LOQs of the other compounds were 0.25 and 0.5 μg/L, respectively. The mean recoveries and RSDs at 1, 2, and 10 times the LOQ were 83.6%-115.3% and 2.20%-12.34%, respectively. The proposed method has the advantages of high sensitivity, good stability, and accurate quantification; thus, it is suitable for the simultaneous determination of the 12 prohibited veterinary drug residues in pig urine.

Plasma drug screening using paper spray mass spectrometry with integrated solid phase extraction.

Drug overdoses have risen dramatically in recent years. We developed a simple nontargeted method using a disposable paper spray cartridge with an integrated solid phase extraction column. This method was used to screen for ~160 fentanyl analogs, synthetic cannabinoids, other synthetic drugs, and traditional drugs of abuse in over 300 authentic overdose samples collected at emergency departments in Indianapolis. A solid phase extraction step was implemented on the paper spray cartridge to enable subnanograms per milliliter synthetic drugs screening in plasma. Analysis was performed on a quadrupole orbitrap mass spectrometer using the sequential window acquisition of all theoretical fragment ion spectra approach in which tandem mass spectrometry was performed using 7 m/z isolation windows in the quadrupole. Calibration curves with isotopically labeled internal standards were constructed for 35 of the most frequently encountered synthetic and traditional illicit drugs by US toxicology labs. Additional qualitative-only drugs in a suspect screening list were also included. Limits of detection in plasma for synthetic cannabinoids ranged from 0.1 to 0.5 and 0.1 to 0.3ng/mL for fentanyl and its analogs and between 1 and 5ng/mL for most other drugs. Relative matrix effects were evaluated by determining the variation of the calibration slope in 10 different lots of biofluid and found to be between 3% and 20%. The method was validated on authentic overdose samples collected from two emergency departments in Indianapolis, Indiana, from suspected or known overdoses. Commonly detected synthetic drugs included fentanyl related substances, designer benzodiazepines such as flubromazolam, and the synthetic cannabinoid 5F-PB-22.

Determination of two perfluorinated compounds in urine by liquid chromatography-tandem mass spectrometry

Objective: To establish a method for the determination of two perfluorinated compounds in urine by liquid chromatography-tandem mass spectrometry. Methods: In November 2022, urine samples were extracted by acidic methanol, purified by WAX solid phase extraction column, and eluted with methanol water, then Waters ACQUITY UPLC BEH C18 column (100 mm×2.1 mm, 1.7 μm) was used with 1.0 mmol/L ammonium acetate solution and methanol as mobile phase. The gradient elution was carried out, the detection was carried out by electrospray negative ion multiple response monitoring (MRM) mode, and the quantitative method was internal standard method. Results: Perfluorooctanoic acid and perfluorooctane sulfonic acid had a good linear relationship in the concentration range of 0.5-50.0 μg/L, and the correlation coefficient was >0.999. The limit of detection was 0.017 μg/L, and the limit of quantitation was 0.005 μg/L. The average recoveries were 96.3% and 101.8%, respectively. Days of precision were 3.5%-6.2% and 3.1%-7.4%, respectively, daytime precision were 4.3%-6.8% and 4.7%-8.1%, respectively. Conclusion: The established method of liquid chromatography-tandem mass spectrometry is high sensitivity and accuracy, and is suitable for the determination of perfluorooctanoic acid and perfluorooctane sulfonic acid in human urine.

Determination of pesticide residue in soil samples by molecularly imprinted solid-phase extraction method

Abstract Porous molecularly imprinted polymer (MIP) microspheres were synthesized via iniferter-suspension polymerization method, employing lenacil (LA) as the template molecule and methacrylic acid (MAA) as the functional monomer. The host–guest complexes formed using LA and MAA were characterized by hydrogen nuclear magnetic resonance and ultraviolet–visible absorption spectroscopy. The obtained results showed that the interaction between LA and MAA mainly relied on hydrogen bonding. The surface morphologies and chemical structures of the MIPs were characterized by scanning electron microscopy. MIPs were spherical in shape with a relatively regular sphericity, rough surface structure, and numerous small holes, which significantly reduced the mass transfer resistance of the template molecules and exhibited excellent recognition performance for template molecules. In addition, soil samples were pretreated with solid-phase extraction columns molecularly imprinted with LA, and analyzed by high-performance liquid chromatography. The recoveries of LA, bromacil, and terbacil were up to 89.65%, 53.17%, and 44.63%, respectively. The developed method showed a minimum detection limit of 10–50 µg·mL−1. In view of the continuous increase of public requirements for pesticide residue detection, a versatile pretreatment method was developed that is green, rapid, simple, and can be miniaturized.

Application of surface-imprinted polymers in pretreatment for detection of sulfamonomethoxine in water samples

A novel surface molecularly imprinted polymer, NH2-MIL-125@MIPs (formed by wrapping a molecularly imprinted polymer around the surface of a MOF carrier NH2-MIL-125) was successfully synthesized by using sulfamonomethoxine as the template. It was used as the adsorbent for solid-phase extraction of sulfonamide antibiotics. The morphology and structure of this polymer was characterized. The polymer was used as the column packing for the homemade solid phase extraction column. The solid phase extraction conditions were optimized to obtain the optimal operation parameters. A method for the detection of trace sulfonamide antibiotics in water was established. The method was evaluated with good linearity in the range of 0.01 μg mL−1 –5.00 μg mL−1. The recoveries of eight SAs ranged from 89.7 % to 107.0 % at the spiked levels of 1, 2 and 3 μg mL−1, and the relative standard deviations of 6 repetitive experiments for eight SAs are always less than 10 %. Real sample results demonstrated that the homemade solid-phase extraction column could be successfully applied to pretreat and quantify sulfonamide in aqueous samples at a trace level.

Customized anion-exchange covalent organic frameworks for efficient extraction of natural products

Extracting highly value-added products from natural systems with low concentrations and complex constituents is of great significance but remains a massive challenge. Herein, a series of dual-functional covalent organic frameworks with both anion exchange and pore adsorption abilities are designed and fabricated using the quaternary amine monomer doping strategy. Attributed to abundant ion exchange sites and selective pore adsorption, the COFs demonstrate high selectivity and loading capacity and fast adsorption for natural products (glycyrrhetinic acid, a high-value natural product), surpassing commercially available materials. Additionally, high-purity (>99%) glycyrrhetinic acid with a >90% extraction efficiency from natural fermentation systems is successfully achieved using a solid-phase extraction column with COFs as the separation medium. The separation column demonstrates outstanding reusability and reproducibility, providing great potential for COFs to serve as robust separation mediums for challenging natural product purification.

Molecularly imprinted photopolymers combined with smartphone-based optical sensing for selective detection of bisphenol A in foods.

Bisphenol A (BPA), known for its endocrine-disrupting properties and potential to leach into food products, has led to significant food safety concerns. Therefore, the development of sensitive and selective BPA rapid detection methods is crucial. In this study, molecularly imprinted solid-phase extraction coupled to a colorimetric method was adopted for the smartphone-based determination of BPA. The molecularly imprinted polymer (MIP) was prepared via photopolymerization and used as a selective adsorbent material for SPE columns. The solid-phase extraction (SPE) columns with multiple cycles significantly reduced the extraction time to only 30 min. The developed method demonstrates useful sensitivity for BPA (LOD = 30 ppb). Furthermore, BPA migration from plastic packaging was evaluated under different storage conditions, revealing that microwave treatment for 5 min led to BPA release from polycarbonate packaging in juice and basic solutions. The MIP selective extraction/clean-up and smartphone-based optical sensor were successfully applied to BPA standard solutions and complex food samples (e.g., juice and tap water), resulting in reproducible and selective BPA determination (RSD ≤ 6%, n = 3). This rapid and cost-effective method of producing MIPs for BPA offers a promising solution for fast and low-cost sensing for on-site fresh food analysis.

Internal multiple interactions-adsorption and external zwitterionic polymer-exclusion of restricted access materials as adsorbent for offline and online extraction of neonicotinoid pesticides in Goji samples

A method based on novel restricted access materials (RAMs) for the determination of neonicotinoid pesticides in Goji samples using offline and online solid phase extraction (SPE) coupled with high-performance liquid chromatography (LC). RAMs were synthesized using poly(chloromethylstyrene-co-divinylbenzene) (PVBC/DVB) microspheres as substrate, styrene (St) and n-vinylpyrrolidone (NVP) were first copolymerized on the interior to construct adsorption sites, and sulfobetaine methacrylate (SBMA) was then polymerized on the exterior to form exclusion sites via two-step surface initiated-atom transfer polymerization. The prepared PVBC/DVB@poly(St-co-NVP)@poly(SBMA) RAMs could efficiently extract neonicotinoid pesticides and automatically exclude proteins. Under the optimized conditions, the developed methods of offline (magnetic SPE and SPE column) and online extraction coupled with LC both using PVBC/DVB@poly(St-co-NVP)@poly(SBMA) RAMs as the extractant, exhibit a wide linearity, low limits of detection and limit of quantification and good inter-day and intra-day precision with satisfactory recoveries. Among these methods, online extraction coupled with LC based on novel RAMs exhibits clear advantages for the determination of neonicotinoid pesticides in Goji samples has clear advantages, such as simple operation by direct injection, short extraction times, and high accuracy with less human error.

Simultaneous determination of six benzodiazepine sedatives residue in aquatic products by high performance liquid chromatography-triple quadrupole mass spectrometry

To establish a method for the simultaneous determination of 6 benzodiazepine sedatives residue in aquatic products by high performance liquid chromatography-triple quadrupole mass spectrometry. The samples were extracted with acetonitrile and purified by C_(18 )solid phase extraction column. The sample solution was separated by Waters ACQUITY UPLC BEH C_(18 )column(2.1 mm×50 mm, 1.7 μm) using 0.1% formic acid and methanol as mobile phase for gradient elution, determined in multiple reaction monitoring mode and quantified by internal standard method. Six benzodiazepine sedatives had a good linear relationship in the range of 1.0-50.0 μg/L with r>0.9990, the limits of detection and limits of quantification were 0.3 and 1.0 μg/kg. Average recoveries for the analytes at 3 spiked levels ranged from 74.2%-108.0% with relative standard deviations of 1.1%-6.7%(n=6). The method is simple, rapid, sensitive and accurate, which is suitable for simultaneous determination of 6 benzodiazepine sedatives residue in aquatic products.

Determination of three new herbicide residues in soil, sediment and water by liquid chromatography-tandem mass spectrometry

Herbicides play an important role in preventing and controlling weeds and harmful plants and are increasingly used in agriculture, forestry, landscaping, and other fields. However, the effective utilization rate of herbicides is only 20%-30%, and most herbicides enter the atmosphere, soil, sediment, and water environments through drift, leaching, and runoff after field application. Herbicide residues in the environment pose potential risks to ecological safety and human health. Therefore, establishing analytical methods to determine herbicide residues in environmental samples is of great importance. In this study, an analytical method based on liquid chromatography-tandem mass spectrometry (LC-MS/MS) in positive electrospray ionization mode (ESI+) was developed for the determination of isoxaflutole, metazachlor, and saflufenacil residues in soil, sediment, and water. The instrumental detection parameters, including electrospray ionization mode, mobile phase, and chromatographic column, were optimized. The mobile phases were methanol (A) and 0.1% formic acid aqueous solution (B). Gradient elution was performed as follows: 0-1.0 min, 60%A; 1.0-2.0 min, 60%A-90%A; 2.0-3.0 min, 90%A; 3.0-4.0 min, 90%A-60%A; 4.0-5.0 min, 60%A. The samples were salted after extraction with acetonitrile and cleaned using a C18 solid-phase extraction column. Different solid-phase extraction columns and leaching conditions were investigated during sample pretreatment. Working curves in the neat solvent and matrix were constructed by plotting the measured peak areas as a function of the concentrations of the analytes in the neat solvent and matrix. Good linearities were found for isoxaflutole, metazachlor, and saflufenacil in the solvent and matrix-matched standards in the range of 0.0005-0.02 mg/L, with r≥0.9961. The matrix effects of the three herbicides in soil, sediment, and water ranged from -10.1% to 16.5%. The limits of detection (LODs, S/N=3) for isoxaflutole, metazachlor, and saflufenacil were 0.05, 0.01, and 0.02 μg/kg, respectively. The limits of quantification (LOQs, S/N=10) for isoxaflutole, metazachlor, and saflufenacil were 0.2, 0.05, and 0.05 μg/kg, respectively. The herbicides were applied to soil, sediment, and water at spiked levels of 0.005, 0.1, and 2.0 mg/kg, respectively. The average recoveries for isoxaflutole, metazachlor, and saflufenacil in soil, sediment, and water were in the ranges of 77.2%-101.9%, 77.9%-105.1%, and 80.8%-107.1%, respectively. The RSDs for isoxaflutole, metazachlor, and saflufenacil were in the ranges of 1.4%-12.8%, 1.2%-7.7%, and 1.5%-11.5%, respectively. The established method was used to analyze actual samples collected from four different sites in Zhejiang Province (Xiaoshan, Taizhou, Dongyang, and Yuhang) and one site in Heilongjiang (Jiamusi). The proposed method is simple, rapid, accurate, stable, and highly practical. It can be used to detect isoxaflutole, metazachlor, and saflufenacil residues in soil, sediment, and water and provides a reference for monitoring the residual pollution and environmental behavior of herbicides.

Determination of twelve halobenzoquinones in drinking water by solid phase extraction-ultra-performance liquid chromatography-tandem mass spectrometry

To establish a method for twelve halobenzoquinones(HBQs) in drinking water by solid phase extraction-ultra-performance liquid chromatography coupled with electrospray-tandem mass spectrometry(SPE-UPLC-MS/MS). The drinking water was acidified with formic acid and concentrated by Bond Elut Plexa solid phase extraction column. The sample solution was separated using Waters ACQUITY HSS T3 column(100 mm×2.1 mm, 1.8 μm) with gradient elution using methanol-water containing 0.1% formic acid as mobile phase. The target compouds were detected in negtive electrospray ionization(ESI~-) and multiple reaction monitoring. The concentration of twelve HBQs showed good linearity in the range 5.0-150.0 ng/mL, respectively, with the correlation coefficients greater than 0.999. The limits of detection(LOD) of twelve HBQs were lower than 2.0 ng/mL, and the limits of quantification(LOQ) for twelve HBQs were lower than 5.0 ng/mL, respectively. The recoveries of three levels in the matrix were 70.0%-84.0%. The matrix effffect was 0.08-0.64. The SPE-UPLC-MS/MS method has high sensitivity, good accuracy and fast analysis speed for the detection of halobenzoquinones in drinking water.

Rapid Screening of 34 Emerging Contaminants in Surface Water by UHPLC-Q-TOF-MS.

To establish a rapid screening method for 34 emerging contaminants in surface water by ultra-high performance liquid chromatography-quadrupole-time of flight mass spectrometry (UHPLC-Q-TOF-MS). The pretreatment conditions of solid phase extraction (SPE) were optimized by orthogonal experimental design and the surface water samples were concentrated and extracted by Oasis® HLB and Oasis® MCX SPE columns in series. The extracts were separated by Kinetex® EVO C18 column, with gradient elution of 0.1% formic acid aqueous solution and 0.1% formic acid methanol solution. Q-TOF-MS 'fullscan' and 'targeted MS/MS' modes were used to detect 34 emerging contaminants and to establish a database with 34 emerging contaminants precursor ion, product ion and retention times. The 34 emerging contaminants exhibited good linearity in the concentration range respectively and the correlation coefficients (r) were higher than 0.97. The limit of detection was 0.2-10 ng/L and the recoveries were 81.2%-119.2%. The intra-day precision was 0.78%-18.70%. The method was applied to analyze multiple surface water samples and 6 emerging contaminants were detected, with a concentration range of 1.93-157.71 ng/L. The method is simple and rapid for screening various emerging contaminants at the trace level in surface water.

4D-Printed Elution-Peak-Guided Dual-Responsive Monolithic Packing for the Solid-Phase Extraction of Metal Ions.

Four-dimensional printing (4DP) technologies are revolutionizing the fabrication of stimuli-responsive devices. To advance the analytical performance of conventional solid-phase extraction (SPE) devices using 4DP technology, in this study, we employed N-isopropylacrylamide (NIPAM)-incorporated photocurable resins and digital light processing three-dimensional printing to fabricate an SPE column with a [H+]/temperature dual-responsive monolithic packing stacked as interlacing cuboids to extract Mn, Co, Ni, Cu, Zn, Cd, and Pb ions. When these metal ions were eluted using 0.5% HNO3 solution as the eluent at a temperature below the lower critical solution temperature of polyNIPAM, the monolithic packing swelled owing to its hydrophilic/hydrophobic transition and electrostatic repulsion among the protonated units of polyNIPAM. These effects resulted in smaller interstitial volumes among these interlacing cuboids and improvements in the elution peak profiles of the metal ions, which, in turn, demonstrated the reduced method detection limits (MDLs; range, 0.2-7.2 ng L-1) during analysis using inductively coupled plasma mass spectrometry. We studied the effects of optimizing the elution peak profiles of the metal ions on the analytical performance of this method and validated its reliability and applicability by analyzing the metal ions in reference materials (CASS-4, SLRS-5, 1643f, and Seronorm Trace Elements Urine L-2) and performing spike analyses of seawater, groundwater, river water, and human urine samples. Our results suggest that this 4D-printed elution-peak-guided dual-responsive monolithic packing enables lower MDLs when packed in an SPE column to facilitate the analyses of the metal ions in complex real samples.

IgG glycopeptide enrichment using hydrophilic interaction chromatography-based solid-phase extraction on anaminopropyl column.

The sample preparation step is pivotal in glycoproteomic analysis. An effective approach in glycoprotein sample preparation involves enriching glycopeptides by solid-phase extraction (SPE) using polar stationary phases in hydrophilic interaction liquid chromatography (HILIC) mode. The aim of this work is to show how different experimental conditions influence the enrichment efficiency of glycopeptides from human immunoglobulin G (IgG) on an aminopropyl-modified SPE column. Different compositions of the elution solvent (acetonitrile, methanol, and isopropanol), along with varying concentrations of elution solvent acidifiers (formic and acetic acid), and different concentrations of acetonitrile for the conditioning and washing solvents (65%, 75%, and 85% acetonitrile) were tested to observe their effects on the glycopeptide enrichment process. Isopropanol proved less effective in enriching glycopeptides, while acetonitrile was the most efficient, with methanol in between. Higher formic acid concentrations in the elution solvent weakened the ionic interactions, particularly with sialylated glycopeptides. Substituting formic acid with acetic acid led to earlier elution of more glycopeptides. The acetonitrile concentration in conditioning and washing solutions played a key role; at 65% acetonitrile, glycopeptides were not retained on the SPE column and were detected in the flow-through fraction. Ultimately, it was proven that the enrichment method was applicable to human plasma samples, resulting in a significant decrease in the abundances of non-glycosylated peptides. To the best of our knowledge, this study represents the first systematic investigation into the impact of the mobile phase on glycopeptide enrichment using an aminopropyl-modified SPE column in HILIC mode. This study demonstrates the substantial impact of even minor variations in experimental conditions, which havenot yet beenconsidered in the literature, on SPE-HILIC glycopeptide enrichment. Consequently, meticulous optimization of these conditions is imperative to enhance the specificity and selectivity of glycoproteomic analysis, ensuring accurate and reliable quantification.

Controllable synthesis of uniform flower-shaped covalent organic framework microspheres as absorbent for solid-phase extraction of trace 2,4-dichlorophenol.

Controllable synthesis of micro-flower covalent organic frameworks (MFCOFs) with controllable size, monodisperse, spherical, and beautiful flower shape was realized by using 2,5-diformylfuran (DFF) and p-phenylenediamine (p-PDA) as building blocks at room temperature. High-quality MFCOFs (5 - 7μm) were synthesized by controlling the kind ofsolvent, amounts of monomers, catalyst content, and reaction time. The synthesized MFCOFs possessed uniform mesopores deriving from the intrinsic pores of frameworks and wide-distributed pores belonging to the gap between the petals. The MFCOFs-packed solid-phase extraction (SPE) column shows adsorption capacity ofabout 8.85mgg-1 for 2,4-dichlorophenol (2,4-DCP). The MFCOF-based SPE combined with the HPLC method was established for the determination of 2,4-DCP in environmental water. The linear range of this method is 20-1000ngmL-1 (R2 > 0.9994), and limit of detection (S/N = 3) is 10.9ngmL-1. Spiked recoveries were 94.3-98.5% with relative standard deviations lower than 2.3%.

Speciation and cycling of iodine in the subtropical North Pacific Ocean

Iodine intersects with the marine biogeochemical cycles of several major elements and can influence air quality through reactions with tropospheric ozone. Iodine is also an element of interest in paleoclimatology, whereby iodine-to-calcium ratios in marine carbonates are widely used as a proxy for past ocean redox state. While inorganic iodine in seawater is found predominantly in its reduced and oxidized anionic forms, iodide (I−) and iodate (IO3−), the rates, mechanisms and intermediate species by which iodine cycles between these inorganic pools are poorly understood. Here, we address these issues by characterizing the speciation, composition and cycling of iodine in the upper 1,000 m of the water column at Station ALOHA in the subtropical North Pacific Ocean. We first obtained high-precision profiles of iodine speciation using isotope dilution and anion exchange chromatography, with measurements performed using inductively coupled plasma mass spectrometry (ICP-MS). These profiles indicate an apparent iodine deficit in surface waters approaching 8% of the predicted total, which we ascribe partly to the existence of dissolved organic iodine that is not resolved during chromatography. To test this, we passed large volumes of seawater through solid phase extraction columns and analyzed the eluent using high-performance liquid chromatography ICP-MS. These analyses reveal a significant pool of dissolved organic iodine in open ocean seawater, the concentration and complexity of which diminish with increasing water depth. Finally, we analyzed the rates of IO3− formation using shipboard incubations of surface seawater amended with 129I−. These experiments suggest that intermediate iodine species oxidize to IO3− much faster than I− does, and that rates of IO3− formation are dependent on the presence of particles, but not light levels. Our study documents the dynamics of iodine cycling in the subtropical ocean, highlighting the critical role of intermediates in mediating redox transformations between the major inorganic iodine species.

Cytotoxicity of water supply in a Palestinian refugee camp and a Syrian informal tented settlement in Lebanon.

Deficient water, sanitation, and hygiene (WASH) significantly account for a high burden of disease across the globe. Lebanon, an Eastern Mediterranean lower-middle-income country with a polluted environment, a fragmented healthcare system, and an ongoing severe economic crisis, faces serious challenges in sustaining safe water supplies, especially in vulnerable communities, while also hosting the world highest refugee population per capita. This study aimed to examine the mutagenicity, and the estrogenic and androgenic activities of water supplies, across both a Palestinian refugee camp and a Syrian informal settlement. Water samples were collected from two targeted camps in Dbayeh and Choueifat, North and South of the Capital City Beirut, respectively, between the months of September and October 2022. Microbial and physicochemical properties of samples were determined, including fecal contamination, total dissolved solids, and various minerals and salts. Organic pollutants were extracted using pre-packed solid phase extraction (SPE) columns, and then mutagenicity of extracts was examined using the Ames test in two Salmonella typhi bacterial strains. The estrogenic and androgenic activities of extracts were assessed using the yeast estrogen and androgen screen tests assays (YES/YAS). Results show excessive levels of total coliforms and total dissolved solids (TDS) in samples from both sites. In addition, the water supply from the Dbayeh Palestinian refugee camp is mutagenic, while the water supply from the Choueifat Syrian informal settlement shows anti-androgen activity. Our findings provide valuable WASH baseline data in two major vulnerable communities in Lebanon, and highlight the importance of a water toxicity testing approach concomitant with a water safety plan, based on a holistic strategy that covers all stages of the water supply chain.

Evaluation of organo-vermiculites as sorbent phases for solid-phase extraction of ibuprofen from water.

The study of ibuprofen (IBU) preconcentration was carried out making use of a homemade column for solid-phase extraction (SPE), using vermiculite (VT) or organo-vermiculites (OVTs) as sorbent phases. Aqueous samples (50.0 mL) percolated the column and IBU was sorbed onto the VT or OVT and then desorbed using acetonitrile. Employing this SPE system and OVT, calibration curves were generated for IBU, by spectrophotometric quantification using the α-naphthylamine method. R2 values higher than 0.9950 and LOD between 12 and 18 μg L-1 were observed, for real enrichment factors of 21 and 31, by using OVTs. The analytical protocol was applied to three water samples, which were spiked with IBU solutions to evaluate the precision and accuracy of the method. Recoveries between 77 and 110% at three different IBU concentrations and RSD lower than 18% were observed, even by using the spectrophotometric method. The protocol developed in this study demonstrated that the OVT was appropriate to work as a preconcentration phase for IBU determination in water samples.

Effect of spacer length between N atoms of linear alkyl triamines on adsorption of anionic platinum(IV) ions

In this study, the effect of carbon chain length between N atoms in linear alkyl triamines on the adsorption of anionic platinum ions was studied. For this purpose, bis(3-aminopropyl)amine (BAPA-SG) and diethylenetriamine (DETA-SG) groups were covalently bonded to the silica gel surface. The modified silica gels were characterized through C, H, N elemental analyses and FTIR spectroscopy before being utilized for adsorption and preconcentration Pt(IV) ions from aqueous solutions. Various factors influencing the batch adsorption of Pt(IV) ions with BAPA-SG and DETA-SG, such as nitric acid, chloride, initial Pt(IV) concentration, and contact time, were investigated. The adsorption of Pt(IV) ions was most efficient in the solutions containing 0.1 M hydronium and 0.1 M chloride ions. The adsorbed amount of Pt(IV) increased with an increase in the initial concentration of Pt(IV). The adsorption of Pt(IV) ions with BAPA-SG and DETA-SG reached equilibrium in 2 and 4 h, respectively. The kinetics of Pt(IV) adsorption on both modified silica gels were found to be compatible with the Pseudo-second-order kinetic model. Langmuir isotherm accurately described the adsorption Pt(IV) ions with BAPA-SG and DETA-SG, with maximum monolayer adsorption capacities of 158.7 and 227.3 mg/g, respectively. In the column solid phase extraction studies, Pt(IV) ions could be quantitatively recovered from 500 mL sample solutions using both modified silica gels by eluting with acidic thiourea solutions. The recovery of Pt(IV) by DETA-SG from chloride-containing solutions was more effective than with BAPA-SG. As a result, it was concluded that diethylenetriamine-bonded silica gel could adsorb Pt(IV) ions more effectively than bis(3-aminopropyl)amine bonded silica gel.