Solid-phase Extraction Technique Research Articles

Proteins Pre-concentration Using Glycidyl Methacrylate-co-stearyl Methacrylate-<i>co</i>-ethylene Glycol Dimethacrylate Monolith

Solid-phase extraction technique is considered as a vital tool in a pre-treatment of different samples. Therefore, it was used as a beneficial and alternative extraction method over the liquid–liquid extraction in diverse applications such as food, environmental, and biological analyses. Glycidyl methacrylate-co-stearyl methacrylate-co-ethylene glycol dimethacrylate (GMA-co-SMA-co-EDMA) monolithic sorbent was prepared as strong cationic-reversed phase sorbent for solid-phase extraction of different proteins. The monolithic sorbent was prepared inside two moulds such as glass microchip device and borosilicate. The morphological properties have been investigated using the Brunauer-Emmett-Teller (BET) model analyzer and scanning electron microscope (SEM), and the formation of the monolithic sorbent was examined using the FT-IR. Eight proteins (cytochrome C, insulin, myoglobin, lysozyme, β-lactoglobulin, trypsin, albumin chicken egg white, and apo-transferrin) with different molecular weight and isoelectric point were investigated for pre-concentration using the SCX/RP sorbent. It was found that the highest extraction recovery was obtained with three proteins cytochrome C, lysozyme, and myoglobin compared with the other proteins. These three proteins were chosen for pre-concentration using the glass microchip. Sorbent performance showed significant results in terms of stability and reproducibility.

Multiresidue determination of pesticide in fishery products by a tandem solid-phase extraction technique

In order to simplify the survey of pesticide (including carbamate, organochlorine, organophosphate and synthetic pyrethroid pesticides) residues in fishery products (including bivalve, crustacean, fish and cuttlefish), multiresidue determination methods were developed through a solid phase extraction (SPE) technique. In the present procedures, samples were extracted with acetonitrile except for bivalve and cuttlefish samples. Mixed solvent of water, acetone and acetonitrile was added to bivalve prior to homogenization, whereas water was needed in cuttlefish samples for blending. For both kinds of sample, an additional procedure of salting-out was needed during extraction. Tandem SPE cartridges of C18 and aminopropyl, using acetonitrile as the only solvent, were used to clean up extracts from either method. A total of 91 pesticides in four major pesticide groups were tested in this study. Gas chromatography (GC, equipped with electron capture detector and flame photometric detector) and high-performance liquid-chromatography (HPLC) equipped with fluorescence detector were used for analysis. The validation of the method was evaluated for each fishery product using samples spiked with all pesticide standards at three concentration levels. The results indicated percentage of recovery ranged from 60% - 120% and coefficients of variation < 20% for all but 10 of the pesticides analyzed (including 1-naphthol, 3-hydroxy carbofuran, aldicarb sulfoxide, heptachlor, trifuralin, acephate, dichlorvs, methamidophos, monocrotophos and omethoate). Residue extraction techniques described in this report are rapid and suitable for screening of pesticide residues in monitoring programs.

The screening of organophosphorus, organochlorine and synthetic pyrethroid pesticides residues in beef fat by tandem solid-phase extraction technique

For regulatory monitoring of pesticides in environmental matrices, a multiresidue analysis through solid phase extraction (SPE) technique and using gas chromatographic determination of organochlorine(OC), organophosphorus(OP) and synthetic pyrethroid pesticides residues in beef fat was studied. The group of pesticides was added to dissolved beef fat (0.5 g) and blended with 8% de-activation florisil. The florisil/fat mixture was packed into disposable filtration columns. This column was tandem with an octadecyl SPE column and was eluted with acetonitrile. The pesticide residues were determined by gas chromatography with electron capture and flame photometric detectors. Three kinds (including OC, OP and synthetic pyrethroid) with a total of 71 pesticides (including their metabolites) were tested in this study. With the exception of isoxthion and flucythrinate with high recovery rates (122% ± 13% and 137% ± 31%, respectively), according to the correlation coefficients for the 71 extracted pesticide standard curves (ranging from 0.9915 ± 0.0176 to 0.9999 ± 0.0200, n = 5), average recovery rate (ranging from 68 ± 9% to 117 ± 11%, n = 25 for each insecticide), inter-assay variability (ranging from 3 ± 3% to 17 ± 12%, n = 25 for each insecticide), intra-assay variability(ranging from 3 to 19%, n = 5 for each insecticide) indicated that the methodology is acceptable for the extraction, determination, and screening of theses residues in beef fat. The detection limits for OCs, OPs and synthetic pyrethroid pesticides are 2-21 ng/g, 6-31 ng/g and 3-118 ng/g, respectively. Comparing with studies conducted by the National Analytical Reference Laboratory in Western Australia in the field of pesticide residue testing in beef fat, the results indicated that the present method could accurately measure commonly used pesticide chemicals.

Determination of organochlorine and nitrogen-containing pesticide residues fish with different fat content

A rapid and multiresidue method for determination the residues of organochlorine and nitrogen-containing pesticides in the different fat content fish by solid-phase extraction (SPE) technique was developed. In the present procedures, samples were extracted with acetonitrile. The extracts were cleaned up by a tandem SPE column of C18 and florisil, using acetonitrile as the only solvent. Residues were determined by gas chromatography equipped with electron capture detector. Recovery was obtained by three concentration levels of 12 organochlorine pesticides and their metabolites (chlorobenzilate, dieldrin, endosulfan sulfate, endosulfan, endrin, heptachlor, heptachlor epoxide, lindane, methoxchlor, p,p'-DDE, p,p'-DDT) and two nitrogen-containing pesticides (alachlor and trifluralin) from 9 fishes with 1.2-23.3% of fat content, respectively. The recoveries of the spiked pesticides residues from the fishes of different fat contain (fat < 10%, fat ≥ 10 but < 20%, and fat ≥ 20%) were in the range from 73.4% to 119.6%. There were no significant difference in the recovery between pesticides concentration and fat content. The recoveries of two samples were not included because of coutaminated by p,p'-DDT and endosulfan separately, or disruption by sample matrix.

Camellia oil saponins: Solid phase extraction and its effect on mice blood and organs

In this study, the tea saponin extracted experiment was adopted to optimize extraction conditions. The solid phase extraction technique was used to extract saponin from camellia tea oil. Four macro-porous resins (DM301; NKA-9; HZ-841; S-8), two cation exchange resins (D001; 732), chitosan and diatomite, respectively, were used in a preliminary experiment; the HZ-841 macro-porous resin was determined as the optimal solid adsorbent material. The extraction conditions were; temperature 23.78 ºC; adsorption time 5.20 hour; liquid-to-solid ratio 12.54:1; predicted adsorption rate 20.20%; ethanol concentration 83.27%; eluent flow rate 1.18 mL/min; liquid-to-solid ratio 21.85:1; and the elution rate of tea saponin was calculated as 59.55%. The effect of tea seed oil saponin on mice blood and organs (liver, kidney, spleen and heart) was studied. The mice were randomly divided into six groups and fed for 90-days. Their weights were recorded every day. On the last day of the experiment serum ele­ments: Total cholesterol (TC), triglycerides (TG), low and high-density lipoproteins (LDL, HDL), as well as AST (aspartate aminotransferase), ALT (alanine aminotransferase) and total protein (TP) and organ (liver, kidney, spleen and heart) histopathologies were determined. The study results demonstrated that tea oil saponin expanded TC, TG, LDL and HDL. However, it generally increased ALT, AST activities and TP values compared to control groups. Tea oil saponin had no effect on organ tissue histopathology compared to control groups.

Magnetic Solid-Phase Extraction Based on Poly 4-Vinyl Pyridine for HPLC-FLD Analysis of Naproxen in Urine Samples.

A magnetic solid phase extraction technique followed by liquid chromatography with a fluorescence detector for naproxen analysis in human urine samples was developed. The method includes the extraction of naproxen with a magnetic solid synthetized with magnetite and poly 4-vinylpriridine, followed by the magnetic separation of the solid phase and desorption of the analyte with methanol. Under optimal conditions, the linear range of the calibration curve was 0.05–0.60 μg L−1, with a limit of detection of 0.02 μg L−1. In all cases values of repeatability were lower than 5.0% with recoveries of 99.4 ± 1.3%. Precision and accuracy values are adequate for naproxen (Npx) analysis in urine samples.

Chiral Ionic Liquids: Structural Diversity, Properties and Applications in Selected Separation Techniques.

Ionic liquids (ILs) are chemical compounds composed of ions with melting points below 100 °C exhibiting a design feature. ILs are commonly used as the so-called green solvents, reagents or highly efficient catalysts in varied chemical processes. The huge application potential of ionic liquids (IL) justifies the growing interest in these compounds. In the last decade, increasing attention has been devoted to the development of new methods in the synthesis of stable chiral ionic liquids (CILs) and their application in various separation techniques. The beginnings of the successful use of CILs to separate enantiomers date back to the 1990 s. Most chiral ILs are based on chiral cations or chiral anions. There is also a limited number of CILs possessing both a chiral cation and a chiral anion. Due to the high molecular diversity of both ions, of which at least one has a chiral center, we have the possibility to design a large variety of optically active structures, thus expanding the range of CIL applications. Research utilizing chiral ionic liquids only recently has become more popular. However, it is the area that still has great potential for future development. This review aimed to describe the diversity of structures, properties and examples of applications of chiral ionic liquids as new chiral solid materials and chiral components of the anisotropic environment, providing chiral recognition of enantiomeric analytes, which is useful in liquid chromatography, countercurrent chromatography and other various CIL-based extraction techniques including aqueous biphasic (ABS) extraction systems, solid–liquid two-phase systems, liquid–liquid extraction systems with hydrophilic CILs, liquid–liquid extraction systems with hydrophobic CILs, solid-phase extraction and induced-precipitation techniques developed in the recent years. The growing demand for pure enantiomers in the pharmaceutical and food industries sparks further development in the field of extraction and separation systems modified with CILs highlighting them as affordable and environmentally friendly both chiral selectors and solvents.

Optimization of QuEChERS Method for Simultaneous Determination of Neonicotinoid Residues in Pollinator Forage.

Consistent with the large-scale use of pesticide seed treatments in U.S. field crop production, there has been an increased use of neonicotinoid-treated corn and soybean seed over the past decade. Neonicotinoids can move downwind to adjacent off-field pollinator habitats in dust from planting and/or move downslope to habitats in surface water. The extent of potential neonicotinoid exposure to pollinators from neonicotinoid movement into these adjacent pollinator habitats is unclear. Pollen and leaf tissue extractions were completed using a quick, easy, cheap, effective, rugged, and safe (QuEChERS) extraction procedure. Samples were subjected to a clean-up step using dispersive solid-phase extraction (dSPE) techniques prior to analysis. The compounds in the extracts were separated on a reversed-phase column with gradient elution and confirmed with tandem mass spectrometry. The extraction method showed acceptable recoveries of analytes ranging from 78.4 to 93.6% and 89.4 to 101% for leaf tissue and pollen, respectively. The method’s detection limits ranged from 0.04 to 0.3 ng/g in milkweed leaf tissue and 0.04 to 1.0 ng/g in pollen. The method is currently being employed in ongoing studies surveying pollen from a diversity of forbs and milkweed leaves obtained from habitat patches established within fields with a history of using neonicotinoid-treated seeds.

Synthesis and characterisation of porous polyvinylpyrrolidone-co-poly(divinylbenzene) (PVP-co-PDVB) copolymer resins for the isolation of betalains from red beetroot

Betalain is a natural pigment with serious antioxidant and biological activities currently used as a food colourant, however; the isolation of this compound is difficult because of its instability. The research was aimed to synthesise and characterise the copolymeric adsorbents for the recovery of betalains by means of the solid-phase extraction (SPE) technique. For this purpose, divinylbenzene (crosslinker) was polymerised with polyvinylpyrrolidone containing vinyl groups by using free radical polymerisation, and toluene was used as a porogene. Polymeric resins in different polyvinylpyrrolidone/divinylbenzene (PVP/DVB) and toluene/divinylbenzene (Tol/DVB) rates were synthesised. The effects of these parameters on the polymerisation efficiency, size distribution, morphology, swelling properties and adsorption capacities of adsorbents were investigated in the later characterization stage. Adsorption tests were conducted by analyzing phenol adsorption in batch model systems. The KOD-4 coded adsorbent exhibited the best performance in adsorption tests with PVP/DVB and Tol/DVB ratios of 0.5 and 1.5, respectively. The betalains were recovered strongly from the red beet juice via the packed bed adsorption column system filled with KOD-4. Then, column reusability and regeneration were studied. In total, the prepared column system was used five times. Ultimately, the results of this study can lead to wide-scale application of betalain-enriched beetroot extracts in the food, pharmaceutical, and cosmetic industries due to their antioxidant and colourant properties as well as their biological activities.

Study on the removal of aesthetic indicators by ozone during advanced treatment of water reuse

Aesthetics and water quality are primary issues of concern for sustainable water reuse since aesthetically unpleasant color and odor are likely to induce public misgiving. This study utilizes aesthetic indicators and other bulk water quality parameters for evaluation. It is found that ozonation during advanced treatment processes in a full-scale water reclamation plant (WRP) could achieve satisfactory performance in decolorization and oxidation of aromatic and humic contents. As limited efficacy on odor removal was detected in the WRP, this study further researched the removal of the main odorant substances 2-methylisokanol (2-MIB) and geosmin (GSM) with different ozone dosage using solid-phase extraction (SPE) and gas phase mass spectrometry (GC–MS) techniques. According to the first-order reaction kinetics, it is inferred that competitive reactions during ozonation by organic matters and restricted CT values are major factors affecting the odor removal. As such, additional treatment approaches such as nanofiltration (NF) are suggested to be consider for aesthetic control towards sustainable and long-term reclaimed water use.

The Presence of Caffeic Acid in Cerebrospinal Fluid: Evidence That Dietary Polyphenols Can Cross the Blood-Brain Barrier in Humans

Epidemiological data indicate that a diet rich in plant polyphenols has a positive effect on brain functions, improving memory and cognition in humans. Direct activity of ingested phenolics on brain neurons may be one of plausible mechanisms explaining these data. This also suggests that some phenolics can cross the blood-brain barrier and be present in the brain or cerebrospinal fluid. We measured 12 phenolics (a combination of the solid-phase extraction technique with high-performance liquid chromatography) in cerebrospinal fluid and matched plasma samples from 28 patients undergoing diagnostic lumbar puncture due to neurological disorders. Homovanillic acid, 3-hydroxyphenyl acetic acid and caffeic acid were detectable in cerebrospinal fluid reaching concentrations (median; interquartile range) 0.18; 0.14 µmol/L, 4.35; 7.36 µmol/L and 0.02; 0.01 µmol/L, respectively. Plasma concentrations of caffeic acid (0.03; 0.01 µmol/L) did not correlate with those in cerebrospinal fluid (ρ = −0.109, p = 0.58). Because food (fruits and vegetables) is the only source of caffeic acid in human body fluids, our results indicate that the same dietary phenolics can cross blood-brain barrier in humans, and that transportation of caffeic acid through this barrier is not the result of simple or facilitated diffusion.

A SIMPLE AND RUGGED BIOANALYTICAL METHOD DEVELOPMENT AND VALIDATION OF BRIVUDINE IN HUMAN PLASMA BY USING HIGH-PERFORMANCE LIQUID CHROMATOGRAPHY

Objective: The current research work focus to simple and rugged bioanalytical method development and validation of brivudine in human plasma using high-performance liquid chromatography.&#x0D; Methods: The analyte (Brivudine) and internal standard (Sofosbuvir) were extracted using the Solid Phase Extraction (SPE) technique. The chromatographic separation was accomplished by using Zorbax eclipse XDB-C18 Column (150×4.6 mm, 5 μm) with a mobile phase consisted of Methanol: 0.5% Ortho-phosphoric acid (65:35%, v/v) respectively, at a flow rate of 0.7 mL/min. The developed method was validated by performing system suitability, carryover effect, linearity, selectivity, sensitivity, precision, accuracy, recovery, ruggedness, and stability studies. The method was validated as per USFDA guidelines.&#x0D; Results: The selected chromatographic condition was found to efficiently separated brivudine (RT-3.55 min) and ISTD (RT-7.87 min). The assay demonstrated a linear dynamic range of 85.205 to 4500.246 ng/ml for brivudine in human plasma with r2&gt;0.99. Demonstrated the lowest limit of detection at 85.205 ng/ml. This method established an intra-run and inter-run precision within the range of 2.99-6.31%CV and 3.67-5.80%CV, respectively. Additional intra-run and inter-run accuracy were within the range of 97.55-105.37% and 99.27-102.15%, respectively. The mean percentage recovery of brivudine and ISTD studies proved good extraction efficiency and the robustness was also evaluated.&#x0D; Conclusion: A simple, accurate, precise, linear and rugged RP-HPLC method was developed and validated for the estimation of brivudine in human plasma with K2EDTA anticoagulant and suitable for conducting BA/BE and TDM.

Determination of Mancozeb and Maneb using flow injection chemiluminescence detection

ABSTRACTA rapid flow injection chemiluminescence method is developed to determine mancozeb and maneb fungicides in natural water samples in the range 0.0025–0.25 ppm (R2 = 0.9996, n = 6) and 0.01–0.75 ppm (R2 = 0.9994, n = 6) with limit of detections of 0.001 and 0.005 ppm (S/N = 3), relative standard deviations of 1.75% and 1.8% and 200 h–1injection throughputs, respectively. The method is based on diperiodatonickelate(IV)-rhodamine 6-G-Brij-35 chemilu-minescence reaction in potassium hydroxide medium enhanced by mancozeb and maneb. Several other oxidising agents instead of diperiodatonickelate(IV) are checked and diperiodatoargentate(III) enhanced appreciably the emission chemiluminescence intensity. Mancozeb and maneb are extracted from water samples by solid-phase extraction technique with the calculated recoveries in the range of 92–108% and relative standard deviations of 1.41–2.67%. The probable chemiluminescence mechanism is proposed with the help of UV-Vis spectrophotometric and CL studies.

Exhaled Breath Analysis for Assessment of IBD (Inflammatory Bowel Disease) Based on Electronic Nose System

Introduction The diagnosis and differentiation of IBD (Inflammatory Bowel Disease) lacks a single gold standard. IBD commonly suffers from a delay in time from first occurrence of symptoms to diagnosis, especially in young patients with ileal disease, which hinders our ability to alter the progression of disease. Also, once the diagnosis of IBD is made its sub categorization into CD (Crohn’s Disease) or UC (ulcerative colitis) is critical for determining the optimal treatment strategy. It is important to identify at risk population that could benefit from a therapeutic approach [1]. Metabolomics studies have recently enter the field of IBD. A variety of studies have been conducted to be significantly different between CD, UC and heathy controls [2]. Limitation for use of metabolomics markers would be too time-consuming and expensive for assessment of IBD or invasive testing in cases. An ideal approach regarding IBD assessment is that breath metabolome offers great potential with simply, easy to use, non-invasive, cheap, rapid and reproducible [3]. An electronic nose system, which is an instrument comprises an array of chemical sensors with partial specificity and an appropriate pattern recognition system capable of recognition simple or complex odors [4], has been suggested a potential alternative as a novel approach for breath analytic technique.In this presentation, we introduce exhaled breath analysis for assessment of IBD from controls and CD from UC using an electronic nose system incorporating a solid-phase micro extraction (SPME) technique. Method We have been developed an electronic nose system composed one chip type array of chemical sensors, chamber, data acquisition system with microprocessor, and sampling system for SPME fiber operation for non-invasive heath care monitoring. The 2x4 sensor array in the system consisted of three oxides of SnO2, NiO2, and In2O3 using Au, Pt, and Pd as catalyst and fabricated on one chip by glancing angle deposition method [5]. A chamber was used to maintain the stable operating temperature of sensor array, and SPME fiber used transferring of exhaled breath samples for measurement. Figure 1 is shown electronic nose system which has been used for experimental work in the hospital. The collection of exhaled breath for IBD patients (23 CD, 32 UC) and 15 controls was carried out using tedlar bag in connection with mouthpiece having a saliva trap to prevent humidity. The SPME fiber coated 85μm Polyacrylate was inserted into the tedlar bag and exposed to the collected breath at an ambient temperature. The system exposed the fiber to the heated sensor array desorbing the volatile off the fiber directly onto the sensors in the chamber. The collection and measurement of expiration were conducted in a hospital after approval of the IRB (Institutional Review Board) at Dongsan Medical Center, Deagu, Korea. Results and Conclusions The primary result for collected data from electronic nose system is shown at Figure 2 using Linear Discriminant Analysis (LDA) algorithm. As shown in Figure 2, IBD patients and controls are distinguished, especially IBD subgroup between CD and UC is well separated each other. However, some samples from UC subgroup are mixed with controls. In this study, we implemented an electric nose system by fabricating a one chip sensors array incorporating SPME sampling technique. Throughout the experimental result, we investigate the possibility of classification between IBD including 2 subgroup discrimination and controls. However, we need more research to improve discrimination regarding UC and controls following by optimal VOCs markers between UC and control including instrument control.

3D graphene–carbon nanotubes-based solid-phase extraction technique combined with GC–MS for the determination of organophosphorus pesticides in water samples

Three-dimensional graphene–carbon nanotubes were prepared by the chemical reduction of a mixed aqueous solution of carboxylated multiwalled carbon nanotubes (C-MWCNTs) and graphene oxide, followed by freeze-drying. C-MWCNTs were then introduced into a three-dimensional graphene aerogel. The obtained three-dimensional graphene–carbon nanotubes were used as a solid-phase adsorbent for the determination of four organophosphorus pesticides (OPPs) in water using GC–MS. Under the optimal extraction conditions, good linearity was achieved between 0.5 and 500 μg L−1 with a correlation coefficient of 0.9993–0.9998. The limits of detection (S/N = 3) and limits of quantification (S/N = 10) for the OPPs ranged from 0.28 to 0.52 and 0.96 to 1.64 μg L−1, respectively. The accuracy of the proposed method was evaluated by measuring the recovery of spiked samples, which ranged from 94.8 to 103.5%, with relative standard deviations lower than 7.0% (n = 3). This method was applied to the determination of target analytes in wetland water, lake water, and river water, and the results showed that the three-dimensional graphene–carbon nanotubes have great potential for the determination of OPPs in real water samples.

Razvoj SPE-HPLC-DAD metode za određivanje florfenikola i florfenikol amina u cerebrospinalnoj tekućini svinja

A study of florfenicol (FF) and its metabo- lite florfenicol amine (FFA) in pig cerebrospinal fluid was conducted following repeated intramuscular administration of the original (reference) and a generic veterinary medicinal product (VMP) under the same experimental conditions (20 mg FF/kg body weight, 48-hour interval). Both VMPs are solutions for injection containing FF as an active substance in the concentration of 300 mg/mL and have been authorized in Croatia for use in cattle and pigs. In this study, clinically healthy pigs were randomly divided into three groups. The first group was treated with the reference VMP, the second with the generic VMP, while the third served as the control group. Animals were sacrificed at 216, 288 and 384 hours after the first drug administration. Cerebrospinal fluid samples were analysed by the optimized and validated high-performance liquid chromatography-diode array detector method (HPLC-DAD). The solid-phase extraction (SPE) technique was chosen for sample preparation. The HPLC-DAD method provides good linearity over the concentration range of 0.05 to 5.00 μg/mL for FF and FFA. Limits of detection were 0.0023 μg/mL for FF and 0.0100 μg/mL for FFA. Extraction recoveries of FF were from 86.6% to 111.8%, and of FFA from 91.7% to 98.8%. The SPE-HPLC-DAD method has been demonstrated to be a selective, sensitive and suitable analytical method for the determination of FF and FFA in cerebrospinal fluid. The present study was based on a preliminary study that quantified FF in pig plasma at 216 hours after the first application of reference or generic VMP. However, FF and FFA were not detected in any of the cerebrospinal fluid samples during the experimental period. According to the nature of biological fluids, the SPE-HPLC-DAD method can be suitable for further pharmacokinetic studies of FF in pig plasma and serum after intramuscular administration of VMPs.

Sources apportionment and carcinogenic risk of polycyclic aromatic hydrocarbons in gas phase of urban Shanghai: Based on high volume solid phase extraction (Hi-volume SPE).

Polycyclic aromatic hydrocarbons (PAHs) are ubiquitous environmental pollutants, posing potentially serious threats to human health. This study analyzed compositional characteristics, sources, and carcinogenic risks of PAHs in the atmospheric gas phase at an urban site in Shanghai, East China. Seventy-four gas phase samples were collected during the warm months of May-October 2018 using a high-volume solid phase extraction (Hi-volume SPE) technique. The total concentration of sixteen priority PAHs (ΣPAHs) was in the range of 5.54-182.05ngm-3 (average 34.47ngm-3) and the total of seven carcinogenic PAHs (ΣCPAHs) was in range of 0.03-1.49ngm-3 (average 0.48ngm-3), accounting for 1.47% of ΣPAHs and indicating low carcinogenic potential. Redundancy analyses indicated positive correlations between ΣPAHs and air quality, and ΣCPAHs and average high temperature, and a negative correlation between ΣPAHs and wind speed. Four possible sources, namely petroleum and petrogenic sources, traffic emissions, coal combustion, and mixed gasoline and coal combustion sources, were identified by positive matrix factorization (PMF), accounting for 62.84%, 19.31%, 10.15%, and 7.69% of ΣPAHs, respectively. The overall lifetime lung cancer risk (LLCR) through inhalation of PAHs was estimated to be at a low risk level of 1.61×10-5. The LLCR based on PMF apportionment decreased in the order of mixed gasoline and coal combustion sources (47.07%)>traffic emissions (35.10%)>petroleum and petrogenic sources (11.06%)>coal combustion (6.74%). This study demonstrates the effectiveness of Hi-volume SPE in collecting and analyzing atmospheric gas phase PAHs.

Preparation of a magnetic polystyrene nanocomposite for dispersive solid-phase extraction of copper ions in environmental samples

The core shell nanostructure of magnetic polystyrene (PS@Fe3O4) was prepared and its physic-chemical properties were studied FT-IR, SEM, TEM, VSM and BET + BJH. The new adsorbent was applied in the dispersive solid phase extraction technique for measuring copper ions in water, Soil and Oyster samples. Analysis is carried out using a flame atomic absorption spectrometry system. Effective parameters on extraction efficiency, such as pH of extraction solution, sorbent dosage, contact time, concentration and volume of desorption eluent and desorption time were optimized using one at a time method. N2 adsorption-desorption experiment resulted in high BET surface area (32.002 m2 g−1) and large pore volume (0.1794 cm3 g−1) for PS@ Fe3O4 nanocomposite. Under the optimum conditions, a calibration curve within the range of 5–40 ng mL−1 with an appropriate coefficient of determination (R2) of 0.9946 was obtained. Preconcentration factor (PF) and limit of detection (LOD) were found to be 55 and 1.6 ng mL−1, respectively. The repeatability and reproducibility for three replicate measurements at the concentration of 25 ng mL−1 were 2.5%–1.4%, respectively. The Freundlich adsorption isotherm and pseudo-second-order kinetic model were consistent to experimental data in adsorption mechanism study. The maximum adsorption capacity was 19.56 mg g−1 for Cu (II). Finally, the efficiency of the method was investigated for analysis of the copper in environmental samples and good relative recoveries (RR%) were obtained within the range of 99.2% to 101.2%.

Production, Preparation and Characterization of Microalgae-Based Biopolymer as a Potential Bioactive Film

Six microalgae strains were screened according to their biomass productivity and polymer synthesis, showing biomass productivity between 0.14 and 0.68 g/(L·d) for a 21-day growth period. Extracellular biopolymers from the spent culture media of Nostoc sp. (No), Synechocystis sp. (Sy), and Porphyridium purpureum (Pp) was obtained, and the yields of the clean biopolymer were 323, 204, and 83 mg/L, respectively. The crude biopolymer was cleaned up using a solid-phase extraction technique. The emulsification index E24 values for the clean biopolymer were 77.5%, 68.8%, and 73.3% at 0.323, 0.083, and 0.204 mg/mL, respectively. The clean biopolymer of the No strain showed the highest fungal growth inhibition against Fusarium verticillioides (70.2%) and Fusarium sp. (61.4%) at 2.24 mg/mL. In general, transparent and flexible biofilms were prepared using biopolymers of No and Pp. The microstructural analysis revealed the presence of pores and cracks in the biofilms, and the average roughness Ra values are 68.6 and 86.4 nm for No and Pp, respectively, and the root mean square roughness Rq values are 86.2 and 107.2 nm for No and Pp, respectively.

Preparation and application of a novel magnetic molecularly imprinted polymer for simultaneous and rapid determination of three trace endocrine disrupting chemicals in lake water and milk samples.

Exposure to endocrine disruptor substances will alter the function of the endocrine system and then cause adverse effects on human health. Among these endocrine disrupting chemicals, hexestrol, nonylphenol, and bisphenol A are most commonly used worldwide. In this study, we aim to develop a simple, rapid, and efficient analytical method for the simultaneous determination of trace hexestrol, nonylphenol, and bisphenol A in lake water and milk samples. A magnetic molecularly imprinted polymer-assisted magnetic solid-phase extraction technique was applied. The magnetic molecularly imprinted polymer was prepared and characterized by electron scanning microscopy and Fourier transform infrared spectroscopy. Subsequently, different experiments were conducted to optimize the magnetic solid-phase extraction conditions. High-performance liquid chromatography with UV detection was employed to determine hexestrol, nonylphenol, and bisphenol A. Limits of detection of the developed method were from 0.1 to 0.3μgL-1 and spiked recoveries ranged from 89.9 to 102.5%, with a relative standard deviation of < 2.5% (intraday). Results obtained from this study showed that the proposed magnetic solid-phase extraction method was a simple, rapid, and sensitive sample pre-treatment method for the determination of trace hexestrol, nonylphenol, and bisphenol in different aqueous samples.