Ahmed A Abdala
Texas A&M University, Chemical Engineering, Faculty Member
- Hamad Bin Khalifa University, College of Science and Engineeirng, Faculty MemberThe Petroleum Institute, Chemical Engineering, Faculty Memberadd
- Polymer Nanocomposites, Nanomaterials, Graphene, Polymer Chemistry, Chemical Engineering, Nanoparticles, and 20 moreHeat and Mass Transfer, Nanoscience, Nanotechnology, Reactor Design, GAS CHEMICAL ENGINEERING, Petroleum refining and petrochemicals, Reaction Kinetcis, Reaction Engineering Course, Light Scattering, Uv Curing, Dynamic Light Scattering, Graphene Oxide, Polymer Rheology, Water soluble polymers, Ceramic Composites, Synthesis and structure of new organic inclusion compounds (host-guest chemistry), Inclusion Compounds, Engineering, Water Treatment, and Polymeric Membranesedit
- Associate Professoredit
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An efficient one-pot multicomponent protocol was developed for the synthesis of arylbenzodioxy xanthenedione scaffolds using mesoporous PbO nanoparticles as reusable catalyst under solvent-free ball milling conditions.
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Nanostructured composites of graphene and highly dispersed sub-20 nm sized ZnO nanoparticles (TRGZ) were prepared via a novel method combining freeze-drying and thermal annealing.
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IIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIW US007659350B2 (12) United States Patent ao) Patent no.: us 7,659,350 B2 Prud'Homme et al. (45) Date of Patent: Feb. 9,2010 (54) POLYMERIZATION METHOD FOR FORMATION OF THERMALLY... more
IIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIW US007659350B2 (12) United States Patent ao) Patent no.: us 7,659,350 B2 Prud'Homme et al. (45) Date of Patent: Feb. 9,2010 (54) POLYMERIZATION METHOD FOR FORMATION OF THERMALLY EXFOLIATED GRAPHITE OXIDE CONTAINING POLYMER (75) Inventors: Robert K. Prud'Homme, Lawrenceville, NJ (US); Ilium A. Aksay, Princeton, NJ (US); Douglas Adamson, Skillman, NJ (US) (73) Assignee: The Trustees of Princeton University, Princeton, NJ (US) ( * ) Notice: Subject to any disclaimer, the term of this patent ...
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Composites of high-density polyethylene (HDPE) and expanded graphite (EG) are prepared for heat exchangers in multi-effect distillation (MED) desalination. At 50 wt.% EG loading, the thermal conductivity of HDPE was increased by 372%.... more
Composites of high-density polyethylene (HDPE) and expanded graphite (EG) are prepared for heat exchangers in multi-effect distillation (MED) desalination. At 50 wt.% EG loading, the thermal conductivity of HDPE was increased by 372%. Moreover, the surface wettability of the HDPE/EG composite was enhanced by corona and RF plasma treatment as demonstrated by the increase in surface free energy from 28.5 mJ/m2 for untreated HDPE/EG to 55.5 and 54.5 mJ/m2 for HDPE/EG treated by corona and RF plasma, respectively. This enhanced surface wettability was retained over a long time with only a 9% and 18% decrease in RF and corona plasma-treated samples’ surface energy after two months. The viscoelastic moduli and the complex viscosity profiles indicated that EG content dictates the optimum processing technique. At loading below 30 wt.%, the extrusion process is preferred, while above 30 wt.% loading, injection molding is preferred. The plasma treatment also improved the HDPE/EG composite ove...
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Due to the shortage of freshwater availability, reclaimed water has become an important source of irrigation water. Nevertheless, emergent contaminants such as antibiotics in reclaimed water can cause potential health risks because... more
Due to the shortage of freshwater availability, reclaimed water has become an important source of irrigation water. Nevertheless, emergent contaminants such as antibiotics in reclaimed water can cause potential health risks because antibiotics are nonbiodegradable. In this paper, we report the adsorptive removal of azithromycin (AZM) antibiotics using activated porous carbon prepared from Azolla filiculoides (AF) (AFAC). The influence of the adsorption process variables, such as temperature, pH, time, and adsorbent dosage, is investigated and described. The prepared AFAC is very effective in removing AZM with 87% and 98% removal after the treatment of 75 min, at 303 and 333 K, respectively. The Langmuir, Temkin, Freundlich, and Dubinin–Radushkevich isotherm models were used to analyze the adsorption results. The Freundlich isotherm was best to describe the adsorption isotherm. The adsorption process follows second-order pseudo kinetics. The adsorption was endothermic (ΔH°= 32.25 kJ/...
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Both selenium and reduced graphene oxide have low specific capacitance due to their chemical nature. Nevertheless, their specific capacitance could be enhanced by hybridizing Se nanomaterials with reduced graphene oxide via formation of... more
Both selenium and reduced graphene oxide have low specific capacitance due to their chemical nature. Nevertheless, their specific capacitance could be enhanced by hybridizing Se nanomaterials with reduced graphene oxide via formation of electrochemical double layer at their interfacial area. Therefore, novel Se-nanorods/rGO nanocomposite was successfully synthesized by template free hot reflux route starting with graphene oxide and selenium dichloride. The composite of rGO decorated by Se-nanorods is characterized using X-ray diffractometry (XRD), Raman spectroscopy, Fourier transform infrared spectroscopy (FTIR), X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM), transmission electron microscopy (TEM) and nitrogen adsorption– desorption. The unique architecture of the composite exhibits high specific capacitance of 390 F/ g at 5 mV/s scan rate in 1.0 M KOH solution with ~ 90% cyclic stability after 5000 cycles making it very promising electrode material for...
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In this study, hybrid graphene-Pt/TiO nanostructure were synthesized by single-step, inexpensive and surfactant/organic solvent free route; hydrothermal technique. The physicochemical properties of hybrid graphene-Pt/TiO nanostructure... more
In this study, hybrid graphene-Pt/TiO nanostructure were synthesized by single-step, inexpensive and surfactant/organic solvent free route; hydrothermal technique. The physicochemical properties of hybrid graphene-Pt/TiO nanostructure were carefully analyzed by multiple techniques, including X-ray diffractometer (XRD), X-ray photoelectron spectroscopy (XPS), field emission scanning electron microscope (FESEM) and transmission electron microscope (TEM). The synthesized hybrid nanostructures were utilized as photocatalyst for the degradation of methylene blue (MB) dye under natural environment at average ambient temperature and mean daily global solar radiation, of about 22-25 °C and 374.9 mWh/cm, respectively. The activity performance indicated considerable degradation of methylene blue (MB) dye and was in the following order Gr (13%), TiO (60%) and hybrid graphene-Pt/TiO nanostructure (90%) over 21 min under the natural light illumination. The physiochemical characterization suggest...
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In this study, the effects of the fiber loading, the coupling agent content and the amount of the absorbed humidity on the stress relaxation behavior of the PP/date palm fibers composite material were characterized, using a dynamic... more
In this study, the effects of the fiber loading, the coupling agent content and the amount of the absorbed humidity on the stress relaxation behavior of the PP/date palm fibers composite material were characterized, using a dynamic mechanical analyzer (DMA). The obtained results have indicated that the rate of stress relaxation decreases as the date palm fiber content increases. It is therefore suggested that the presence of the natural fibers in composite materials do not help polymer molecules to recover their original configurations, generally present in the polymer matrix before any mechanical loading. The use of the coupling agent was found to also reduce such rate, due to the improvement of the quality of adhesion between the reinforcing phase and the polymer molecules. By increasing the amount of the absorbed humidity, a higher relaxation rate was obtained. This is an expected result since the presence of water molecules in composite materials encourages the relative movement (sliding) of polymer molecules, reducing therefore their recovering time and these can regain their initial configuration at a higher rate.
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The viscoelastic properties of associative polymers are important not only for their use as rheology modifiers but also to understand their complex structure in aqueous media. In this study, the dynamics of comblike hydrophobically... more
The viscoelastic properties of associative polymers are important not only for their use as rheology modifiers but also to understand their complex structure in aqueous media. In this study, the dynamics of comblike hydrophobically modified alkali swellable associative (HASE) polymers are probed using diffusing wave spectroscopy (DWS) based tracer microrheology. DWS-based tracer microrheology accurately probes the dynamics of HASE polymers, and the extracted microrheological moduli versus frequency profile obtained from this technique closely matches that obtained from rotational rheometry measurements. Quantitatively, however, the moduli extracted from DWS-based tracer microrheology measurements are slightly higher than those obtained using rotational rheometry. The creep compliance, elastic modulus, and relaxation time concentration scaling behavior exhibits a power-law dependence. The length scale associated with the elastic to glassy behavior change is obtained from the time-dependent diffusion coefficient. The Zimm-Rouse type scaling is recovered at high frequencies but shows a concentration effect switching from Zimm to more Rouse-like behavior at higher concentrations.
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A switchable cationic surfactant, e.g., tertiary amine surfactant Ethomeen C12, has been previously described as a surfactant that can be injected in high pressure CO2 for foam mobility control. C12 can dissolve in high pressure CO2 as a... more
A switchable cationic surfactant, e.g., tertiary amine surfactant Ethomeen C12, has been previously described as a surfactant that can be injected in high pressure CO2 for foam mobility control. C12 can dissolve in high pressure CO2 as a nonionic surfactant and equilibrate with brine as a cationic surfactant. Here we describe the adsorption characteristics of this surfactant in carbonate formation materials. The adsorption of this surfactant is sensitive to the equilibrium pH, the electrolyte composition of the brine, and the minerals in carbonate formation materials. Pure C12 is a nonionic surfactant. When it is mixed with brine, the solution has high pH and limited solubility. However, when the surfactant solution in brine is equilibrated with high pressure CO2, the pH is about 4, the surfactant switches to a cationic surfactant and becomes soluble. Thus the adsorption is also a function of pH. The adsorption of C12 on calcite at low pH is low, e.g., 0.5 mg/m2. However, if the car...
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ABSTRACT Conductive polymer composites based on carbon materials are widely used in commercial applications. Herein, electrically conductive melamine-formaldehyde (MF) resin was fabricated by incorporating various loadings of graphite... more
ABSTRACT Conductive polymer composites based on carbon materials are widely used in commercial applications. Herein, electrically conductive melamine-formaldehyde (MF) resin was fabricated by incorporating various loadings of graphite nanosheets (GNS) via in-situ polymerization followed by crosslinking at 165 C. The effect of GNS loading on the electrical conductivity, interfacial properties and thermal stability of the composites is discussed. SEM fractogram confirm the uniform dispersion and toughening of MF upon GNS reinforcement. The electrical percolation was achieved at about 0.9 vol.% loading of GNS suggesting an aspect ratio for GNS between 130 and 240 depending on the model used.
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ABSTRACT Medium-chain-length poly(hydroxyalkanoate)s (PHAmcl) are biodegradable and renewable biopolymers with elastomeric qualities. Here we report on the preparation and characterization of composite materials using thermally reduced... more
ABSTRACT Medium-chain-length poly(hydroxyalkanoate)s (PHAmcl) are biodegradable and renewable biopolymers with elastomeric qualities. Here we report on the preparation and characterization of composite materials using thermally reduced graphene (TRG) nanoparticles as filler with three PHAmcl polymers. The matrices vary with respect to chain packing length, capacity for noncovalent bonding with the TRG surface, and the presence of covalent cross-linking. Results show that the addition of up to 2.5 vol % TRG to PHAmcl increases the melting temperature by 1–3 °C, the modulus by 200–590%, and the electrical conductivity by >7 orders of magnitude. Additionally, we use rheology and microscopy to characterize the composites. We discuss our results in light of polymer entanglement theory and the effects of polymer structure, filler loading volume, and the role of graphene-polymer interfacial forces. We extend our discussion by comparing the modulus enhancements of PHAmcl composites to those reported in other studies in which layered carbon nanofillers are combined with structurally related biopolyesters including: polylactide, polylactide-co-polyglycolide, polycaprolactone, and two other PHA copolymers.
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ABSTRACT Since its recent discovery, graphene has emerged as a promising material for a variety of applications. In this article, thermally reduced graphene (TRG) was produced by thermal exfoliation of graphite oxide; characterized using... more
ABSTRACT Since its recent discovery, graphene has emerged as a promising material for a variety of applications. In this article, thermally reduced graphene (TRG) was produced by thermal exfoliation of graphite oxide; characterized using XRD, SEM, TEM, FTIR, XPS, BET, and elemental analysis; and used as an adsorbent to remove methyl orange (MO) dye from aqueous solution. Langmuir and Freundlich isotherm models are used to examine the nature of the adsorption process and the results indicate that MO adsorption on TRG can be described as monolayer type (Langmuir) adsorption. Moreover, the adsorption process is physical, spontaneous, and follows a second order kinetics as revealed by the analysis of the thermodynamic and kinetic data. Furthermore, the sorption capacity and the removal percentage strongly depend on adsorbent-to-dye ratio, the solution pH and temperature. The current study indicates that graphene could be a very efficient adsorbent for removal of MO dye from colored-waters with a maximum sorption ca
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The following is a summary of the major project activities that have taken place over the completed quarter. For more details, see the individual reports in the last section of this report. ... Objective: To design a review course to... more
The following is a summary of the major project activities that have taken place over the completed quarter. For more details, see the individual reports in the last section of this report. ... Objective: To design a review course to prepare PI students for Fundamentals of ...
USOO8048950B2 <12) United States Patent <10) Patent No.: US 8,048,950 B2 Prud'homme et al. (45) Date of Patent: *Nov. 1, 2011 (54) WIRE COATING CONTAINING THERMALLY 1I<fl$¢hfl1;1eH11~ , , ang et . EXFOLIATED GRAPHITE OXIDE... more
USOO8048950B2 <12) United States Patent <10) Patent No.: US 8,048,950 B2 Prud'homme et al. (45) Date of Patent: *Nov. 1, 2011 (54) WIRE COATING CONTAINING THERMALLY 1I<fl$¢hfl1;1eH11~ , , ang et . EXFOLIATED GRAPHITE OXIDE 7,105,108 B2 9/2006 Kaschak et al. , _ 7,658,901 B2 2/2010 Prud'Homme et al. (75) Inventors: Robert K. Prud homme, Lawrenceville, 7,745,523 B2 >1 6/2010 P111d>HO111111e e1 31' ““ H 524/495 N] (US); Ilhan A. Aksay, Princeton, N] 7,771,824 B2 8/2010 Herrera-Alonso et al. . ' 2002/0054995 A1 5/ ...
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Toluene affects the distribution of APTS on the surface of thermally reduced graphene during the catalyst free silylation.
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36 . However, the strength of this ceramic is similar to or lower than the strength of the polymer used for impregnation, thus strength enhancement is expected by the simple addition of a stronger material. In this study, we present an... more
36 . However, the strength of this ceramic is similar to or lower than the strength of the polymer used for impregnation, thus strength enhancement is expected by the simple addition of a stronger material. In this study, we present an approach to enhance the mechanical properties of strong alumina ceramics through impregnation with acrylate based polymers ranging from homopolymer (poly(methyl methacrylate) (PMMA) to a zwitterionic ionomers with two nonionic monomers, a cationic monomer and an anionic monomer. The pristine alumina ceramic is at least five times stronger than the polymers used. Therefore, in this case a weaker material is used to strengthen a stronger one. The strength enhancement we observe correlates with polymer-alumina interactions on their interface. EXPERIMENTAL Alumina Bars. 52% dense laminated alumina tapes were prepared by tape-casting from 750 nm alumina-particle suspension and sintering at 1300°C for 1 h. Bar dimensions are 25x5x2 mm. Polymer Synthesis. Io...
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Polymer-based composites were heralded in the 1960s as a new paradigm for materials. By dispersing strong, highly stiff fibres in a polymer matrix, high-performance lightweight composites could be developed and tailored to individual... more
Polymer-based composites were heralded in the 1960s as a new paradigm for materials. By dispersing strong, highly stiff fibres in a polymer matrix, high-performance lightweight composites could be developed and tailored to individual applications 1. Today we stand at a similar threshold in the realm of polymer nanocomposites with the promise of strong, durable, multifunctional materials with low nanofiller content 2, 3, 4, 5, 6, 7, 8, 9, 10, 11. However, the cost of nanoparticles, their availability and the challenges that remain to ...
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In this study, graphene oxide (GO) was synthesized using Hummers method. The synthesized GO was characterized using field-emission scanning electron microscopy (FE-SEM), X-ray diffraction (XRD), Fourier transformed infrared (FTIR)... more
In this study, graphene oxide (GO) was synthesized using Hummers method. The synthesized GO was characterized using field-emission scanning electron microscopy (FE-SEM), X-ray diffraction (XRD), Fourier transformed infrared (FTIR) spectroscopy, X-ray photoelectron spectroscopy (XPS), and Brunauer–Emmett–Teller (BET) nitrogen adsorption. The analyses confirmed the presence of oxygen functional groups (C=O and C-O-C) on the GO surface. These oxygen functional groups act as active sites in the adsorption Sr (II). The BET analysis revealed the surface area of GO of 232 m2/g with a pore volume of 0.40 cm3/g. The synthesized GO was used as an adsorbent for removing Sr (II) from aqueous solutions. The adsorption equilibrium and kinetic results were consistent with the Langmuir isotherm model and the pseudo-second-order kinetic model. A maximum strontium adsorption capacity of 131.4 mg/g was achieved. The results show that the GO has an excellent adsorption capability for removing Sr (II) f...
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Silver nanoparticles (Ag NPs) and their nanocomposites with polymers are potent agents for antibacterial and disinfectant applications. The structural parameters of Ag-NPs, such as size, shape, and surface area, are very critical for... more
Silver nanoparticles (Ag NPs) and their nanocomposites with polymers are potent agents for antibacterial and disinfectant applications. The structural parameters of Ag-NPs, such as size, shape, and surface area, are very critical for developing appropriate formulations for the targeted applications. The impact of these factors on the performance of Ag NPs is analyzed. Ag NPs with a broad spectrum of antibacterial activities have already found applications in wound and burn dressing, food preservation, agricultural ponds, treatment for infected areas, coatings, water treatment, and other biomedical applications. Ag NPs are quite useful against antibiotic-resistant bacteria, but their level of toxicity needs careful investigation as their toxicity could be very harmful to human health and the environment. This review discusses the challenges and prospects of various Ag NPs and their composites. The review will enrich the knowledge about the efficiency and mechanism of various Ag nanop...
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Metal-alloys tubes are used in the falling-film evaporator of the multi-effect distillation (MED) that is the dominant and efficient thermal seawater desalination process. However, the harsh seawater environment (high salinity and high... more
Metal-alloys tubes are used in the falling-film evaporator of the multi-effect distillation (MED) that is the dominant and efficient thermal seawater desalination process. However, the harsh seawater environment (high salinity and high temperature) causes scale precipitation and corrosion of MED evaporators’ metal tubes, presenting a serious technical challenge to the process. Therefore, the metal/metal alloys used as the material of the MED evaporators’ tubes are expensive and require high energy and costly tube fabrication process. On the other hand, polymers are low-cost, easy to fabricate into tubes, and highly corrosion-resistant, but have low thermal conductivity. Nevertheless, thermally conductive fillers can enhance the thermal conductivity of polymers. In this article, we carried out a feasibility-study-based techno-economic and socioeconomic analysis, as well as a life-cycle assessment (LCA), of a conventional MED desalination plant that uses titanium tubes and a plant tha...
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Carbonylation reactions with carbon monoxide (CO) provide efficient and attractive routes for the synthesis of bulk and fine chemicals. However, the practice of using large excess of an inflammable, lethal and greenhouse CO gas is always... more
Carbonylation reactions with carbon monoxide (CO) provide efficient and attractive routes for the synthesis of bulk and fine chemicals. However, the practice of using large excess of an inflammable, lethal and greenhouse CO gas is always a concern in this chemistry. The development of CO surrogates have gained substantial interest and becoming a green alternative to gaseous CO. Many of the recent studies have focused on the development of other benign and safe reagents to work as a CO source in carbonylation reactions, and the assortment of feasible CO surrogates for specific reaction can be accomplished by the literature data. This review describes the recent developments in palladium catalyzed carbonyl insertions without the direct use of gaseous CO.
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We report an efficient and facile one-pot synthesis of 4-oxo-tetrahydroindoles using sulfamic acid under ball milling conditions.
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: The ever-increasing resistance of pathogens towards antibiotics and crop disease due to pest has caused serious health problems in recent years. Therefore, there is need of powerful and protective materials for the eradication of... more
: The ever-increasing resistance of pathogens towards antibiotics and crop disease due to pest has caused serious health problems in recent years. Therefore, there is need of powerful and protective materials for the eradication of diseases. Off course, metal/metal oxide nanoparticles are powerful agents due to their fore combating microbial infections. In this context, the present review article discusses the toxicity, fate, effects and applications of metal/metal oxide nanoparticles (M/MO NPs). This is review starts with an introduction, followed by toxicity aspects, antibacterial, and testing methods and mechanisms. In addition, discussion on the impact of different M/MO NPs and their characteristics such as size, shape, particle dissolution on their induced toxicity on food and plants as well as their applications in pesticides. Finally, our prospective on current and future issues and applications is presented.
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Graphene oxide (GO) has shown great promise as a nanofiller to enhance the performance of mixed matrix composite membranes (MMMs) for water treatment applications. However, GO can be prepared by various synthesis routes, leading to... more
Graphene oxide (GO) has shown great promise as a nanofiller to enhance the performance of mixed matrix composite membranes (MMMs) for water treatment applications. However, GO can be prepared by various synthesis routes, leading to different concentrations of the attached oxygen functional groups. In this research, GO produced by the Hummers’, Tour, and Staudenmaier methods were characterized and embedded at various fractions into the matrix of polysulfone (PSf) and used to prepare microfiltration membranes via the phase inversion process. The effects of the GO preparation method and loading on the membrane characteristics, as well as performance for oil removal from an oil-water emulsion, are analyzed. Our results reveal that GO prepared by the Staudenmaier method has a higher concentration of the more polar carbonyl group, increasing the membrane hydrophilicity and porosity compared to GO prepared by the Hummers’ and Tour methods. On the other hand, the Hummers’ and Tour methods p...
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A method for the measurement of total mercury (T-Hg) in environmental samples using cold vapour atomic absorption spectrometry (CV AAS) has been validated yielding a dynamic range (0.04–10.00 μg/kg) and high certified reference material... more
A method for the measurement of total mercury (T-Hg) in environmental samples using cold vapour atomic absorption spectrometry (CV AAS) has been validated yielding a dynamic range (0.04–10.00 μg/kg) and high certified reference material (CRM) recovery (>90%). The validation was carried out according to International Union of Pure and Applied Chemistry (IUPAC) validation and Eurachem Guides. A freeze-dried and homogenised sample was weighed and then digested using Suprapur acids (HNO3, H2SO4, and HF) with potassium dichromate solution in a hot block digestion system. A calibration curve was constructed (R2 > 0.999). Two CRMs (Marine Sediment Reference Material (PACS-3) and Trace Elements in Muscle Tissue (Trace Elements and Methylmercury in Mussel Tissue (NIST2976)) were utilised for quality assurance and control. The limit of quantification (LOQ) calculated as 0.04 µg/kg, and uncertainty (U) calculated as 2%. The obtained results showed the suitability of this method for direc...