Miniaturization of self-assembled solid phase extraction based on graphene oxide/chitosan coupled with liquid chromatography for the determination of sulfonamide residues in egg and honey

Efficacy of new generation biosorbents for the sustainable treatment of antibiotic residues and antibiotic resistance genes from polluted waste effluent

Antimicrobials are frequently used in both humans and animals for the treatment of bacterially-generated illnesses. Antibiotic usage has increased for more than 40% from last 15 years globally per day in both human populations and farm animals leading to the large-scale discharge of antibiotic residues into wastewater. Most antibiotics end up in sewer systems, either directly from industry or healthcare systems, or indirectly from humans and animals after being partially metabolized or broken down following consumption. To prevent additional antibiotic compound pollution, which eventually impacts on the spread of antibiotic resistance, it is crucial to remove antibiotic residues from wastewater. Antibiotic accumulation and antibiotic resistance genes cannot be effectively and efficiently eliminated by conventional sewage treatment plants. Because of their high energy requirements and operating costs, many of the available technologies are not feasible. However, the biosorption method, which uses low-cost biomass as the biosorbent, is an alternative technique to potentially address these problems. An extensive literature survey focusing on developments in the field was conducted using English language electronic databases, such as PubMed, Google Scholar, Pubag, Google books, and ResearchGate, to understand the relative value of the available antibiotic removal methods. The predominant techniques for eliminating antibiotic residues from wastewater were categorized and defined by example. The approaches were contrasted, and the benefits and drawbacks were highlighted. Additionally, we included a few antibiotics whose removal from aquatic environments has been the subject of extensive research. Lastly, a few representative publications were identified that provide specific information on the removal rates attained by each technique. This review provides evidence that biosorption of antibiotic residues from biological waste using natural biosorbent materials is an affordable and effective technique for eliminating antibiotic residues from wastewater.

Theoretical insights into the uptake of sulfonamides onto phospholipid bilayers: Mechanisms, interaction and toxicity evaluation

Sulfonamides (SAs) are now recognized as the main emerging environmental pollutants in aquatic environments. Although the bioaccumulation capacities of SAs have been confirmed, the pathway for the penetration of the SAs into lipid bilayer has been not fully understood. In this study, the bioaccumulation mechanism of four typical SAs onto the dipalmitoyl phosphatidylcholine (DPPC) lipid bilayer and their effects on the properties of DPPC bilayer were employed and evaluated respectively by using molecular dynamics simulations. Results show that from the viewpoint of thermodynamics, it is favorable for these SAs partitioning to DPPC bilayer. The accommodation of four SAs onto the lipid membrane needs to undergo several processes, which include the contact stage, transformation stage, and absorption stage. Besides, the sulfamethoxazole (SMX) and sulfamethazine (SMZ) show a strong preference for the DPPC phase rather than the interface region while the sulfadiazine (SDZ) and sulfametoxydiazine (SMD) have similar tendencies in the interface region and DPPC phase. Furthermore, the cytotoxicity of SAs is reflected in their ability to affect the electrostatic potential of the membrane and to reduce the thickness of phospholipid bilayers. This molecular-level study provided an insightful understanding of the toxicity and bioaccumulation of SAs.

Environmentally friendly analysis of sulphonamides in Brazilian honey through automated and miniaturised sample preparation coupled with LC-MS/MS

Increased use of environmentally friendly practices has become a trend in science because of the current awareness regarding climate change and related issues. Similarly for analytical chemistry, considering the development of greener methods for reducing the use of reagents and samples and also toxic waste generation. To meet such goals, automation, and miniaturisation of sample preparation-a well-recognised laborious and time-consuming analytical step-are two promising strategies. This work associates the greener aspects of miniaturisation and the performance of automated sample preparation. Therefore, we proposed an analytical method using a miniaturised extraction column for pre-concentrating sulphamerazine, sulphamethazine, sulphamethoxazole, sulphadimethoxine, sulphathiazole, and sulphachlorpyridazine from honey and cleaning-up the samples. Several variables were optimised: extractive phase, loading flow, loading phase, and loading time. Under optimised conditions, the method showed adequate linearity between 5.0 and 60 ng g^-1 with R > 0.99, and also good selectivity and recovery (114.6-124.1%) which are acceptable according to Brazilian legislation. Intra and inter-day precision were in the range 3.0-5.0%. Although sulphonamides were detected in one of the eight commercial honey samples, the value was below the established MRL. The method showed efficiency, while also exhibiting greener characteristics resulting from miniaturisation and automation, representing a promising environmentally friendly alternative for conventional sample preparation methods.

Simultaneous preconcentration and determination of sulfonamide antibiotics in milk and yoghurt by dynamic pH junction focusing coupled with capillary electrophoresis

A dynamic pH junction was used in capillary electrophoresis (CE-DAD) to on-line preconcentrate, separate, and determine trace amounts of sulfonamide antibiotics (SAs) in milk and yoghurt samples in this study. A sample matrix with 0.15% acetic acid and 10% methanol (MeOH) at a pH of 4.0, and a background electrolyte (BGE) that contained 35 mM sodium citrate with 10% MeOH at a pH of 8.5, and an acidic barrage of 0.4% acetic acid with 10% MeOH at a pH of 2.5 were utilised to achieve a stacking effect for SAs through a dynamic pH junction. Under optimised conditions, the proposed preconcentration method showed good linearity (30-500 ng/mL, r² ≥ 0.9940), low limits of detection (LODs) of 4.1-6.3 ng/mL, and acceptable analytes recovery (81.2-106.9%) with relative standard deviations (RSDs) within 5.3-13.7 (n = 9). The limits of quantification (LOQs) were below the maximum residue limit approved by the European Union (EU) in this type of matrices. Sensitivity enhancement factors of up to 129 were reached with the optimised dynamic pH junction using CE with a diode array detector (DAD). The method was used to determine SAs in fresh milk, low-fat milk, full-cream milk, and yoghurt samples.

Determination of sulfonamides in milk and egg samples by HPLC with mesoporous polymelamine-formaldehyde as magnetic solid-phase extraction adsorbent

In this work, magnetic mesoporous polymelamine-formaldehyde composites were synthesized via a facile Schiff base reaction. The magnetic mesoporous polymelamine-formaldehyde composites combined both the properties of mesoporous polymelamine-formaldehyde and the magnetism of NH₂ -SiO₂ @Fe₃ O₄ nanoparticles, possessing high specific surface area (150.66 m² g^-1 ) and good magnetism (24.50 emu g^-1 ). The magnetic mesoporous polymelamine-formaldehyde composites were employed as magnetic adsorbent for the extraction of sulfonamides. Under optimal conditions, good linearities with correlation coefficients higher than 0.9984 were obtained between peak area and sulfonamides concentration (2-200 μg L^-1 ) with limits of detection in the range of 0.33-0.58 μg L^-1 . The established method was successfully applied for the determination of sulfonamides in egg and milk samples. The adsorption mechanisms demonstrated that the adsorption of magnetic mesoporous polymelamine-formaldehyde composites toward sulfonamides was a multilayer process, and adsorption kinetics followed the pseudo-second-order model.

Magnetic molecularly imprinted polymers for extraction of S-phenylmercapturic acid from urine samples followed by high-performance liquid chromatography

In this study, magnetic molecularly imprinted polymers (MMIPs) were prepared and used as sorbents for extraction of S-phenylmercapturic acid (S-PMA) from urine samples, followed by high-performance liquid chromatography ultraviolet-visible (HPLC-UV/Vis) analysis. The MMIPs were synthesized by the copolymerization reaction of (phenylthio) acetic acid (template molecule), methacrylic acid (functional monomers) and ethylene glycol dimethacrylate (cross-linkers). The morphology, structure property and surface groups of the prepared MMIPs were characterized by scan electron microscopy, transmission electron microscopy, infrared spectroscopy, X-ray diffraction pattern, thermogravimetric analyses, Brunauer-Emmett-Teller and vibrating sample magnetometer. The selectivity of the MMIPs was investigated in the presence of interferents. Various parameters affecting the S-PMA extraction efficiency were investigated, including MMIPs amount, pH, sample volume, desorption solvent, as well as extraction and desorption time. The obtained optimal parameters were as follows: MMIPs amount (20 mg), pH (3.0), sample volume (5 mL), desorption solvent (methanol/acetic acid [9/1, v/v]), extraction time (30 minutes) and desorption time (2 minutes). The method was validated according to the Food and Drug Administration Guidance for Industry on Bioanalytical Method Validation. The calibration curve for the analyte was linear in the concentration range of 0.030-1.0 mg/L (r = 0.9995). The LOD and LOQ of the method were 0.0080 and 0.0267 mg/L, respectively. The enrichment factor of the MMIPs was 5. The relative standard deviations of intra- and inter-day tests were in the range of 3.8-5.1% and 3.9-6.3%, respectively. The recoveries at three different concentrations of 0.10, 0.50 and 0.80 mg/L ranged between 95.2% and 98.6%. In addition, the MMIPs could be reused for at least eight times. The proposed method was successfully applied to the determination of S-PMA in urine samples. In addition, this developed method could be used as a tool in the early screening and clinical diagnosis of benzene intoxication.

A nanocomposite adsorbent of metallic copper, polypyrrole, halloysite nanotubes and magnetite nanoparticles for the extraction and enrichment of sulfonamides in milk

A composite adsorbent composed of metallic copper (Cu), polypyrrole (PPy), halloysite nanotubes (HNTs) and magnetite nanoparticles (Fe₃O₄) was developed to extract and enrich sulfonamides by dispersive magnetic solid phase extraction. The composite could adsorb sulfonamides via hydrogen bonding and hydrophobic, π-π and π-electron-metal interactions. The extraction conditions were optimized and the developed composite adsorbent was characterized and provided a large surface area that enhanced extraction efficiency for sulfonamides. Coupled with high performance liquid chromatography, the adsorbent was used to quantitatively determine sulfonamides found in milk samples. The response of the developed method exhibited linearity from 5.0 to 150.0 μg kg^-1 for sulfathiazole, and from 2.5 to 100.0 μg kg^-1 for sulfamerazine, sulfamonomethoxine and sulfadimethoxine. Limits of detection were between 2.5 and 5.0 μg kg^-1. Recoveries of sulfonamides in milk samples ranged from 83.0 to 99.2% with RSDs lower than 6%. The developed composite adsorbent showed good reproducibility and reusability.

On-line multi-residue analysis of fluoroquinolones and amantadine based on an integrated microfluidic chip coupled to triple quadrupole mass spectrometry

An on-line multi-residue qualitative and quantitative analysis method for fluoroquinolones and amantadine using an integrated microfluidic chip was developed prior to directly coupling to triple quadrupole mass spectrometry (QQQ-MS). Six parallel channels consisting of sample filtration units and micro solid phase extraction (micro-SPE) columns were present in the specifically designed microfluidic device. Firstly, the impurities in the sample solution were trapped by the micropillars in the filtration units. The solution passed through the micro-SPE units packed with hydrophilic-lipophilic balanced (HLB) particles, and then the two classes of drugs were enriched. After washing, the targets were eluted and immediately electrosprayed for MS analysis. This approach allowed effective filtration, enrichment, elution, and MS detection without the introduction of an additional separation step after SPE. Direct electrospray ionization (ESI)-MS in multiple reaction monitoring (MRM) mode could not only ensure the high sensitivity of quantitative analysis, but also achieved accurate qualitative analysis towards targets using the MRM ratios, reducing the possibility of false positives. Good linear relationships were obtained by the internal standard (IS) method with a linear range of 1-200 ng mL^-1 (R² > 0.992). The mean recoveries of the eight target analytes were from 85.2% to 122% with the relative standard deviation (RSD) ranging from 5.6% to 20.3%. All this demonstrated that the developed microfluidic device could be a useful tool for rapid detection in the field of food safety.

Super-porous semi-interpenetrating polymeric composite prepared in straw for micro solid phase extraction of antibiotics from honey, urine and wastewater

A cryogel-based semi-interpenetrating polymer network (Cryo-SIPN) was prepared in which conductive polymers such as polyaniline (PANI) and polypyrrole (PPy) were formed within the super porous network of acrylic acid cryogel. For completion of cryo-polymerization, all the constituent solutions were severely mixed and placed into the plastic straws and kept at -20°C and then the synthesized cyrogels were cut into the 1-cm length and freeze dried after washing with water. The Cryo-SIPN polymeric composite was applied in micro solid phase extraction (µSPE) of some selected antibiotic residues from various samples. The µSPE method combined with a high performance liquid chromatography-ultraviolet (HPLC-UV) system allowed trace quantification of antibiotic residues in the honey and water samples while the significant variables were optimized using a central composite design (CCD) to find optimum conditions. The method performance was satisfactory with recovery ranges from 70.0 to 109%. The limits of detection (S/N = 3) and quantification (S/N = 10) for all samples were within the 17-50 μg kg^-1 and 47-140 μg kg^-1 range, respectively. The relative standard deviation was less than 10 % for antibiotics in the foodstuff and water samples. The validated Cryo-SIPN-µSPE in conjunction with HPLC-UV, proved to be versatile, efficient and robust while its capability toward the trace determination of drugs residues in real-life samples is demonstrated in this work.

Activated carbon/diatomite-based magnetic nanocomposites for magnetic solid-phase extraction of S-phenylmercapturic acid from human urine

In this study, activated carbon/diatomite-based magnetic nancomposites (denoted as AC/DBMNs) were synthesized and applied as an adsorbent for magnetic solid-phase extraction of S-phenylmercapturic acid (S-PMA) from human urine prior to high-performance liquid chromatography. The surface morphologies and structures of AC/DBMNs were characterized by Fourier transform infrared spectroscopy, transmission and scanning electron microscopy, X-ray diffraction, Brunauer-Emmett-Teller surface area, vibrating sample magnetometer and ζ-potential measurements. The experimental parameters including sample volume, sample pH, adsorbent amount, extraction time, elution solvent and desorption time were investigated in detail. Under the optimum conditions, the method exhibited good linearity (r > 0.9993) within the concentration ranges of 0.03-1.0 mg/L. Moreover, the limits of detection and quantification were 0.01 and 0.03 mg/L, respectively. The enrichment factor was 5, and good recoveries (88.9-97.3%) with relative standard deviations in the range of 5.6-6.8% (n = 6) for inter-day and 6.3-8.1% (n = 6) for intra-day were achieved. The developed method was successfully applied to the analysis of S-PMA in urine samples. In addition, this accurate and sensitive method has great potential to be applied in the early screening and clinical diagnosis of the workers exposed to benzene.

Exploration of a novel triazine-based covalent organic framework for solid-phase extraction of antibiotics

A novel COF was synthesized, which has a similar structure to SNW-1 but different selectivity towards antibiotics.

Determination of Chloramphenicol in Honey and Milk by HPLC Coupled with Aptamer-Functionalized Fe3 O4 /Graphene Oxide Magnetic Solid-Phase Extraction

An aptamer-functionalized Fe₃ O₄ /graphene oxide was synthesized by chemical co-precipitation method and then employed in the magnetic solid-phase extraction for selective enrichment of chloramphenicol before HPLC. The aptamer was covalently bonded to the Fe₃ O₄ /graphene oxide complex by 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide hydrochloride and N-hydroxysuccinimide. Parameters affecting extraction efficiency including solution pH, extraction time and temperature, types and volume of elution solvent, and elution time were investigated in detail. Under the optimal conditions, good linearity was obtained between the peak area and analyte concentration in the range of 7.0 to 1.0 × 10³  µg/L with the correlation coefficient of 0.9994. The limit of detection and quantitation were 0.24 µg/L and 0.79 µg/L, respectively. The developed method was employed to the analysis of chloramphenicol in honey and milk samples. The recoveries ranged from 80.5% to 105.0% with relative standard deviations less than 8.9%. PRACTICAL APPLICATION: An aptamer-functionalized Fe₃ O₄ /graphene oxide was synthesized and employed in magnetic solid phase extraction for the enrichment of chloramphenicol before HPLC. The presented assay was employed for the determination of chloramphenicol in honey and milk with satisfactory results.

Preparation of porous aromatic framework modified graphene oxide for pipette-tip solid-phase extraction of theophylline in tea

A new material called as porous aromatic frameworks modified graphene oxide (PAFs-GO) was synthesized, and it was used as an adsorbent in pipette-tip SPE for the effective purification and enrichment of theophylline in tea sample by HPLC. The properties of PAFs-GO were characterized by field emission SEM, FTIR, thermogravimetry analysis and Brunauer Emmett Teller N₂ adsorption-desorption analysis. The results of static adsorption and dynamic adsorption test showed PAFs-GO had higher adsorption ability (93.25 mg/g) than graphene oxide. The LOD and LOQ of the method were 0.0141 and 0.0471 µg/mL, respectively. The acceptable method reproducibility was found as intra- and inter-day precisions, yielding the RSDs <4.62%. By introducing PAFs as support skeleton, the specific surface area of GO was effectively increased, and the penetrability was improved. Studies showed that the proposed method had been successfully applied for purification and enrichment of theophylline in complex tea matrix.

An ionic liquid-magnetic graphene composite for magnet dispersive solid-phase extraction of triazine herbicides in surface water followed by high performance liquid chromatography

A new ionic liquid-magnetic graphene (IL-MG) composite was used as the adsorbent in magnetic dispersive solid-phase extraction to rapidly extract and isolate triazine herbicides from surface water. IL-MG was synthesized by a simple and time-saving one-pot strategy where the synthesis of magnetic Fe₃O₄, the modification with an IL, and the reduction of graphene oxide to graphene were conducted at the same time. An IL was applied to enrich the interaction mechanism between IL-MG and analytes (π-π, hydrophobic interaction, and electrostatic interaction). Moreover, the IL and Fe₃O₄ nanoparticles acted as spacers, inserting between the layers of graphene to prevent the aggregation of graphene, which improved the adsorption ability because of the large specific surface area of IL-MG. The resultant IL-MG had hierarchical flake structures and showed a high adsorption capacity (8266.0-12 324.1 μg g^-1) toward triazine herbicides. Under suitable conditions, the linearity for triazine herbicides was achieved in the range of 0.55-500 ng mL^-1 with a detection limit of 0.09-0.15 ng mL^-1 and a quantitation limit of 0.31-0.51 ng mL^-1, and the enrichment factor was 83-fold, which indicated that the proposed method could be successfully applied for the determination of triazine herbicides in surface water.

Determination of sulfonamides in milk by capillary electrophoresis with PEG@MoS2 as a dispersive solid-phase extraction sorbent

A synthetic polyethylene glycol-molybdenum disulfide (PEG@MoS₂) composite was prepared using a simple method, and the application of this material in dispersive solid-phase extraction (DSPE) was investigated for the enrichment of eight sulfonamides (SAs) in milk samples. The composite was characterized by energy dispersive spectroscopy, scanning electron microscopy, transmission electron microscopy, Fourier transform infrared spectroscopy and Brunauer-Emmett-Teller measurements. The results showed that the MoS₂ synthesized in the presence of PEG has the advantage of a larger surface area and that the adsorption effect of this MoS₂ was enhanced. After extraction, the eight SAs were separated by capillary zone electrophoresis with a good linear relationship (R² > 0.9902) in the range of 0.3-30 µg ml^-1 and good precision (between 0.32% and 9.83%). Additionally, good recoveries (between 60.52% and 110.91%) were obtained for the SAs in the milk samples. The developed PEG@MoS₂-based DSPE method could be applied for the enrichment of SAs in real milk samples.

Cu@SnS/SnO2 nanoparticles as novel sorbent for dispersive micro solid phase extraction of atorvastatin in human plasma and urine samples by high-performance liquid chromatography with UV detection: Application of central composite design (CCD)

Separation and detection of residual drug in biological fluids has directly related to human health in term of their beneficial or side effects. In biological fluid samples (complex matrix which containing drug at very low level) conduction of preliminary efficient technique as good choice for pre-concentration and clean-up of real sample before their instrumental analysis is highly recommended. In this result technique, based on nano-structure material which poses higher available surface area and larger member of reactive sites led to significant improvement in characteristic performance of analytical method. This paper focused on the synthesis and application of novel nano-sorbent for pre-concentration and extraction of atorvastatin (AT) from different biological fluids. Influence of various variables including sorbent dosage, eluent volume and sonication time on present method response was studied and optimized by central composite design under response surface methodology and accordingly an acceptable calibration curves over wide linear ranges (0.3-2000μgL^-1) with high coefficient of determination higher than 0.999 strongly confirm high applicability of present method for quantification of analyte while limit of detection and quantification in plasma sample were 0.0608 and 0.2033μg L^-1, respectively.

Supercritical fluid extraction of papaverine and noscapine from poppy capsules followed by preconcentration with magnetic nano Fe3O4@Cu@diphenylthiocarbazone particles

A novel magnetite adsorbent modified with copper and diphenylthiocarbazone was synthesized and used as a sorbent for magnetic solid phase extraction (MSPE) of two opium alkaloids: papaverine and noscapine.

Preparation and characterization of chitosan microparticles for immunoaffinity extraction and determination of enrofloxacin

The use of chitosan microparticles as chromatographic support has received much attention. In this study, the effects of process parameters, namely, chitosan molecular weight, chitosan concentration, molar ratio of amino group to aldehyde group, volume ratio of water to oil phase and stirring speed on the size and size distribution of chitosan microparticles and their application for immunoaffinity extraction were extensively investigated. Size distribution analysis indicated that the average diameter of the microparticles was 124μm with Span value of 1.1. The obtained microparticles exhibited low non-specific adsorption and kept stable in the pH range 4.0-10.0. Immunoaffinity chromatography (IAC) column was prepared by coupling antibody against enrofloxacin (ENR) with chitosan microparticles. Further characterization indicated that the binding capacity of the column was 4392ng ENR/mL gel and the variation of ENR extraction efficiency among columns was less than 5.2%. When challenged with ENR-fortified bovine milk samples, recoveries of ENR by immunoaffinity extraction were found to be in the range of 85.9% to 101.9%, demonstrated the feasibility of the prepared IAC columns for sample clean-up in ENR residue determination.