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BACKGROUND: The detection of insecticide resistance in natural populations of Anopheles vectors is absolutely necessary for malaria control. CDC bottle bioassay as a new tools has been employed for detecting the insecticide resistance. For a limit number of mosquito vectors, diagnostic doses and diagnostic times for some insecticides have already been determined using this new assay. For the first time in the area, susceptibility levels of Anopheles stephensi was done with DDT, deltamethrin, and bendiocarb using CDC bottle bioassay and compared results with WHO standard test method. METHODS: Anopheles stephensi were collected in larvae stage from the cisterns of drinking water in Chabahar port which considered as old malaria foci, Sistan and Baluchistan province. The field collected larvae were colonized at the insectary of School of Public Health (SPH), Tehran University of Medical Science. The susceptibility tests were carried out on sugar fed female mosquitoes aged 2-3 days, against DDT 4%, bendiocarb 1% and deltamethrin 0.05% using WHO and CDC susceptibility methods. The mortality and knockdown rates, as well as the parameters of regression analysis, including LT50 and LT90, was calculated separately for the WHO and CDC methods. RESULTS: The 24h mortality rates of An. stephensi were 28.6% and 25.6% for DDT, 60.8% and 64.6% for bendiocarb and 100% for deltamethrin using both WHO and CDC assay at 30 and 60min respectively. The 50% lethal times (LT50) were estimated 44.9 and 66.2min, 38.9 and 81.8min and 0.7 and 15.0min respectively using both WHO and CDC susceptibility tests. CONCLUSION: The similar results of susceptibility levels were shown for DDT, bendiocarb and deltamethrin. The lethal times (LT50) showed significant difference using both WHO and CDC bioassay methods.
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OBJECTIVE: To determine the wash resistance of Olyset® Plus using World Health Organization Pesticide Evaluation Scheme standard washing procedure and to assess the value of knock down and mortality rates of Anopheles stephensi at different regimens of long lasting insecticide treated nets washings. METHODS: The study was conducted at the Bioassay Laboratory of Culicidae Insectary, School of Public Health, Tehran University of Medical Sciences, Iran. The net was made of polyester impregnated with permethrin and piperonyl butoxide at a ratio of 2:1. The washing resistance was assessed using Le Chat® soap and a shaker incubator set at a speed of 155 r/min, 30 °C for 10 min. The cone bioassay test was carried out according to World Health Organization recommended guideline with tolerant field strain of female Anopheles stephensi to pyrethroids. RESULTS: The knockdown and mortality rates of female mosquitoes exposed to Olyset® Plus from un-washed nets to 2 washings were 79.7% and 88.8% respectively. Mortality was dropped to zero while active ingredient estimated 0.532 µg/100 cm2 to 0.481 µg/100 cm2 after 15 washings. A positive correlation was seen between residues of permethrin on nets, knockdown rate and mortality rate of female Anopheles stephensi exposed to different regimes of washed Olyset® Plus (r = 0.954, P = 0.001). CONCLUSIONS: It is recommended that a preliminary survey conducted on resistance level of Anopheles vectors before the distribution of Olyset® Plus in malaria endemic communities.
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BACKGROUND: One of the best ways to control the malaria disease and to be protected human against Anopheles mosquito biting is the use of repellents. Throughout repellents, herbal ones may be an appropriate and safe source for protection. METHODS: Chemical constituents of Achillea vermiculata and Satoreja hortensis were determined by using gas chromatography-mass spectrometry. Efficacy and the protection time of these plants were assessed on Anopheles stephensi under the laboratory condition. RESULTS: The mean assessed protection time and efficacy for A. vermiculata was 2.16 and 3.16 hours respectively and the obtained ED50 and ED90 for this plant was 5.67 and 63 µl/cm(2) respectively. The figured for S. hortensis was 4.16 and 5 hours respectively. ED50 and ED90 for this plant were 5.63 and 45.75µl/cm(2) respectively. CONCLUSION: Results of investigation showed that S. hortensis plant has an acceptable protection time, therefore, this plant could be considered as a good herbal repellent against anopheles mosquitoes.
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In this research, a new sample treatment technique termed solvent-assisted dispersive solid phase extraction (SA-DSPE) was developed. The new method was based on the dispersion of the sorbent into the sample to maximize the contact surface. In this approach, the dispersion of the sorbent at a very low milligram level was achieved by injecting a mixture solution of the sorbent and disperser solvent into the aqueous sample. Thereby, a cloudy solution formed. The cloudy solution resulted from the dispersion of the fine particles of the sorbent in the bulk aqueous sample. After extraction, the cloudy solution was centrifuged and the enriched analytes in the sediment phase dissolved in ethanol and determined by flame atomic absorption spectrophotometer. Under the optimized conditions, the detection limit for lead and cadmium ions was 1.2 µg L(-1) and 0.2 µg L(-1), respectively. Furthermore, the preconcentration factor was 299.3 and 137.1 for cadmium and lead ions, respectively. SA-DSPE was successfully applied for trace determination of lead and cadmium in fruit (Citrus limetta, Kiwi and pomegranate) and water samples. Finally, the introduced sample preparation method can be used as a simple, rapid, reliable, selective and sensitive method for flame atomic absorption spectrophotometric determination of trace levels of lead and cadmium ions in fruit and water samples.
Assuntos
Cádmio/análise , Frutas/química , Chumbo/análise , Extração em Fase Sólida/métodos , Água/análise , Concentração de Íons de Hidrogênio , Concentração Osmolar , Solventes , Espectrofotometria Atômica/métodosRESUMO
We are introducing mercapto-mesoporous carbon modified carbon paste electrode (mercapto-MP-C-CPE) as a new sensor for trace determination of omeprazole (OM) in biological samples. The synthesized modifier was characterized by thermogravimetry analysis (TGA), differential thermal analysis (DTA), transmission electron microscopy (TEM), Fourier transform infrared spectrometry (FT-IR), X-ray diffraction (XRD), elemental analysis (CHN) and N2 adsorption surface area measurement (BET). The electrochemical response characteristic of the modified-CPE toward OM was investigated by cyclic and differential pulse voltammetry (CV and DPV). The proposed sensor displayed a good electrooxidation response to the OM, its linear range is 0.25nM to 25µM with a detection limit of 0.04nM under the optimized conditions. The prepared modified electrode shows several advantages such as high sensitivity, long-time stability, wide linear range, ease of preparation and regeneration of the electrode surface by simple polishing and excellent reproducibility.
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Carbono/química , Técnicas Eletroquímicas/instrumentação , Técnicas Eletroquímicas/métodos , Eletrodos , Omeprazol/análise , Humanos , Limite de Detecção , Microscopia Eletrônica de Transmissão , Omeprazol/sangue , Omeprazol/urina , Porosidade , Reprodutibilidade dos Testes , Espectroscopia de Infravermelho com Transformada de Fourier , Termogravimetria , Difração de Raios XRESUMO
In this paper, we have introduced nanoporous carbon modified with mercapto groups as a new solid-phase method for extraction of cadmium(II) and copper(II) ions. The modified nanoporous carbon sorbent was characterised by thermogravimetric analysis, differential thermal analysis, transmission electron microscopy, Fourier transform infrared spectrometry, X-ray diffraction, and nitrogen adsorption surface area (BET) measurements. Effects of pH value, flow rates, type, concentration and volume of the eluent, breakthrough volume, and effect of other ions were studied. The experimental results show that simultaneous trace cadmium(II) and copper(II) ions can be quantitatively preconcentrated at pH 6.0 with recoveries >97%. Under optimised conditions, limits of detection are 0.04 and 0.09 ng mL(-1) for the ions of cadmium and copper respectively, and the precision of the method for analysis of cadmium and copper ions (5.0 µg of each target ions, N=8) are 2.4% and 2.1%, respectively. The obtained capacities of mercapto-nanoporous carbon were found to be 145 and 95 mg g(-1) for cadmium and copper ions, respectively. The accuracy of the proposed procedure was verified by analysing standard reference material. Finally, the introduced sorbent was successfully applied for trace determination of cadmium and copper ions in food samples.
Assuntos
Cádmio/análise , Carbono/química , Cobre/análise , Análise de Alimentos/métodos , Adsorção , Carboidratos/química , Concentração de Íons de Hidrogênio , Limite de Detecção , Microscopia Eletrônica de Transmissão , Porosidade , Extração em Fase Sólida , Espectrofotometria Atômica , Difração de Raios XRESUMO
The ordered carbohydrate-derived porous carbons (OC-DPCs) were first functionalized with thiol groups (-SH) and then immobilized with gold nanoparticles (AuNPs). The Au-SH-OC-DPCs were characterized by CHN analysis, transmission electron microscopy (TEM), fourier transform infrared spectroscopy (FT-IR), X-ray photoelectron spectroscopy (XPS), and x-ray diffraction (XRD). The Au-SH-OC-DPCs were applied for the fabrication of a new electrochemical sensor. The electrocatalytic capabilities of the new sensor were tested by the oxidation of nicotinamide adenine dinucleotide (NADH) in a 0.1 M Robinson buffer solution (pH 7.0) using cyclic voltammetry (CV), linear sweep voltammetry (LSV), and differential pulse voltammetry (DPV). The Au-SH-OC-DPCs showed a good voltammetric performance in the electrochemical detection of NADH with a low detection limit (1.0 nM), high sensitivity (4.934 µA/µM), and wide linear concentration range (5.0 nM-10 µM).
Assuntos
Carbono/química , Técnicas Eletroquímicas/instrumentação , Ouro/química , Nanopartículas Metálicas/química , NAD/análise , Técnicas Biossensoriais/instrumentação , Eletrodos , Limite de Detecção , Oxirredução , PorosidadeRESUMO
Due to importance of trace analysis of lead and copper ions because of their toxicity, in this paper, for the first time a unique tetragonal star-like morphology of polyaniline was applied as a efficient solid phase for selective trace separation of copper and lead at optimum experimental conditions in shrimp, fish and water samples. Due to the unique star like nanostructure of synthesized sorbent, the tendency of the sorbent toward selective extraction of lead and copper ion in the optimised pH is very interesting. The prepared polymeric resin displayed good figures of merits with analytical calibration curve ranging from 1 to 120 µg L(-1) for copper and 2 to 100 µg L(-1) for lead ions with limits of detection of 0.4 µg L(-1) for copper and 0.9 µg L(-1) for lead, adsorption capacities of 84 and 110 mg g(-1) for copper and lead ions, respectively, extraction efficiency of greater than 96%, and relative standard deviation (RSD) of less than 4% for eight separate column experiments in determination of 5.0 µg of lead and copper. The obtained data for adsorption capacity of the sorbent shows the high tendency of the sorbent toward the mentioned ions in this nanostructure form. Finally, this sorbent can be used as a simple, rapid, reliable, selective and sensitive method for determination of trace levels of Cu(II) and Pb(II).
Assuntos
Compostos de Anilina/química , Nanoestruturas/química , Alimentos Marinhos/análise , Frutos do Mar/análise , Animais , Peixes , Extração em Fase Sólida/métodos , Espectrofotometria Atômica/métodosRESUMO
Magnetic molecularly imprinted polymers have been synthesized for the selective preconcentration and trace determination of lamotrigine (LTG) in urine and plasma samples. The magnetic nanoparticles were modified by tetraethyl orthosilicate and 3-methacryloxypropyl trimethoxysilane before imprinting. The magnetic molecularly imprinted polymers were prepared via surface molecular imprinting technique, using Fe3 O4 as a magnetic component, LTG as template molecule, methacrylic acid as a functional monomer, ethylene glycol dimethacrylate as a cross-linker, and 2,2'-azobisisobutyronitrile as a radical initiator in methanol/acetonitrile (50:50, v/v) as the porogen. The obtained sorbent was characterized using scanning electron microscopy, Fourier-transform infrared spectroscopy, X-ray diffraction, and thermal analysis. Separation of the sorbent from the sample solution was simply achieved by applying an external magnetic field. Determination of the extracted drug was performed by high-performance liquid chromatography with UV detection. Under the optimum extraction conditions, the method detection limits were 0.7 µg/L (based on S/N of 3) for urine samples and 0.5 µg/L for plasma samples. A linear dynamic range of 1-1000 µg/L was obtained for LTF in plasma and urine samples. Finally, the applicability of the proposed method was evaluated by extraction and determination of LTG in urine and plasma samples.
Assuntos
Anticonvulsivantes/isolamento & purificação , Polímeros/química , Extração em Fase Sólida/métodos , Triazinas/isolamento & purificação , Anticonvulsivantes/sangue , Anticonvulsivantes/urina , Humanos , Lamotrigina , Impressão Molecular , Polímeros/síntese química , Extração em Fase Sólida/instrumentação , Triazinas/sangue , Triazinas/urinaRESUMO
A simple, rapid, and efficient sample pretreatment technique, based on solvent-based de-emulsification dispersive liquid-liquid microextraction (SD-DLLME), followed by high performance liquid chromatography (HPLC) has been developed for simultaneous preconcentration and trace detection of 2,4-dichlorophenoxyacetic acid (2,4-D) and 2-methyl-4-chlorophenoxyacetic acid (MCPA) in water and urine samples. Some parameters such as acidity of solution, the amount of salt, type, and volume of extraction solvents, type of disperser/de-emulsifier solvent, and its volume were investigated and optimized. Under optimum extraction conditions, the limits of detections (LODs) of this method for MCPA and 2,4-D were 0.2 and 0.6 µg L(-1) (based on 3S(b)/m) in water and 0.4 and 1.6 µg L(-1) in urine, respectively. Furthermore, dynamic linear range of this method for MCPA and 2,4-D was 1-300 and 2-400 µg L(-1), repectively. Finally, the applicability of the proposed method was evaluated by extraction and determination of the herbicides in urine and different water samples.
Assuntos
Ácido 2,4-Diclorofenoxiacético/análise , Ácido 2-Metil-4-clorofenoxiacético/análise , Herbicidas/análise , Poluentes Químicos da Água/análise , Ácido 2,4-Diclorofenoxiacético/urina , Ácido 2-Metil-4-clorofenoxiacético/urina , Cromatografia Líquida de Alta Pressão , Monitoramento Ambiental , Herbicidas/urina , Limite de Detecção , Microextração em Fase Líquida , Solventes/química , Urina/química , Poluentes Químicos da Água/urinaRESUMO
Graphene oxide-cobalt phthalocyanine (GO-PcCo) hybrid material as a new electrocatalyst was synthesized and used successfully to fabrication of new biosensor for the electrooxidation of l-cysteine (CSH) in aqueous media. Fourier transform infrared spectroscopy (FT-IR), X-ray photoelectron spectroscopy (XPS), thermogravimetric analysis (TGA), and transmission electron microscopy (TEM) images revealed that cobalt phthalocyanine is covalently attachment on graphene oxide sheets as single layers GO-PcCo. Cyclic voltammetric studies showed that the GO-PcCo/glassy carbon electrode (GO-PcCo/GCE) improves electrochemical behavior of CSH oxidation, as compared to the GO and PcCo. In addition, the results indicated that GO and PcCo have a synergic effect in the electrooxidation of CSH. The catalytic oxidation responses were studied and the reaction mechanisms were discussed. The electrocatalytic behavior is further developed as a new detection scheme for CSH by chronoamperometry method and under optimized conditions, excellent analytical features, including high sensitivity and selectivity, low detection limit and satisfactory dynamic range, were achieved.
Assuntos
Técnicas Biossensoriais/métodos , Cisteína/isolamento & purificação , Grafite/química , Óxidos/química , Carbono/química , Cisteína/química , Eletroquímica , Indóis/química , Limite de Detecção , Compostos Organometálicos/química , Oxirredução , Água/químicaRESUMO
A simple, rapid, and efficient method, based on surfactant assisted dispersive liquid-liquid microextraction (SA-DLLME), followed by high performance liquid chromatography (HPLC) has been developed for simultaneous preconcentration and trace detection of zonisamide and carbamazepine in biological samples. A conventional cationic surfactant called cethyltrimethyl ammonium bromide (CTAB) was used as a disperser agent in the proposed approach. 1.5 mL of CTAB (0.45 mmol L(-1)) (disperser solvent) containing 50.0 µL of 1-octanol (extraction solvent) was injected rapidly into the 7.0 mL of water or diluted plasma or urine. A cloudy solution (water, 1-octanol, and CTAB) was formed in the test tube. After formation of cloudy solution, the mixture was centrifuged and 20 µL of collected phase was injected into HPLC for subsequent analysis. Some parameters such as the type and volume of the extraction solvent, the type and concentration of surfactant, pH, ionic strength and centrifugation time were evaluated and optimized. Under optimum extraction conditions, the limits of detections (LODs) were 2.1 and 1.5 µg L(-1) (based on 3Sb/m) for urine samples, and 2.3 and 1.6 µg L(-1) for plasma samples. Linear dynamic range of 5-300 and 5-200 µg L(-1) were obtained for zonisamide and carbamazepine in all samples. Finally, the applicability of the proposed method was evaluated by extraction and determination of the drugs in urine and plasma samples.
Assuntos
Carbamazepina/isolamento & purificação , Isoxazóis/isolamento & purificação , Microextração em Fase Líquida/métodos , Tensoativos/química , 1-Octanol/química , Carbamazepina/sangue , Carbamazepina/urina , Cetrimônio , Compostos de Cetrimônio/química , Cromatografia Líquida de Alta Pressão/métodos , Dissonias , Humanos , Isoxazóis/sangue , Isoxazóis/urina , Modelos Lineares , Concentração Osmolar , Reprodutibilidade dos Testes , Hidróxido de Sódio/química , ZonisamidaRESUMO
A novel sorbent for separation of cadmium ions was prepared by functionalizing multiwall carbon nanotubes with diphenylcarbazide and underutilised to develop a solid-phase extraction method to separate and concentrate trace amounts of cadmium ions from some real samples by flame atomic absorption spectrophotometry measurements. The optimum experimental conditions such as pH, flow rates, type and the smallest amount of eluent for elution of cadmium ions, break through volume and effect of coexisting ions on the separation and determination of cadmium ions were evaluated. In the proposed method, the extraction efficiency for cadmium ions were greater than 97% and limit of detection (LOD) was 0.05 ng mL(-1). The preconcentration factor was 360 for cadmium and the relative standard deviation (RSD) of the method was 2.4%. The adsorption capacity of the modified MWCNT was 86 mg g(-1) for cadmium ions. Validation of the outlined method was performed by analysing certified reference material soil (NCS DC 73323). The practical applicability of the developed sorbent was examined in some real samples.
Assuntos
Cádmio/isolamento & purificação , Nanotubos de Carbono/química , Oryza/química , Extração em Fase Sólida/métodos , Verduras/química , Poluentes Químicos da Água/isolamento & purificação , Adsorção , Cádmio/análise , Difenilcarbazida/química , Contaminação de Alimentos/análise , Limite de Detecção , Extração em Fase Sólida/instrumentação , Poluentes Químicos da Água/análiseRESUMO
Combination of different extraction methods is an interesting and debatable work in the field of sample preparation. In the current study, for the first time, solid phase extraction combined with electro membrane extraction (SPE-EME) was developed for ultra-preconcentration and determination of chlorophenoxy acid herbicides in environmental samples using capillary electrophoresis (CE). In the mentioned method, first, a 100mL of chlorophenoxy acid herbicides (2-methyl-4-chlorophenoxyacetic acid (MCPA), 2-(2,4-dichlorophenoxy) propanoic acid (2,4-DP) and 2-(4-chloro-2-methylphenoxy) propanoic acid (MCPP)) was passed through a column of graphene oxide as a solid phase, and then the adsorbed herbicides were eluted by 4.0mL of 8% acetic acid (HOAC) in methanol. Then, the elution solvent was evaporated and the herbicides residue was dissolved in 4.0mL of double distilled water (pH 9.0). Afterwards, the herbicides in 4.0mL of the aqueous solution were transferred to an EME glass vial. In the EME step, the herbicides were extracted from the sample solution into the basic acceptor solution (pH 13.0) under electrical potential, which was held inside the lumen of the fiber with 1-octanol as the supported liquid membrane (SLM). Under the optimized conditions, high enrichment factors were obtained in the range of 1950-2000. The limits of quantification (LOQs) and method detection limits (MDLs) were obtained in the range of 1.0-1.5 and 0.3-0.5ngmL(-1), respectively. Finally, the performance of the present method was evaluated for extraction and determination of chlorophenoxy acid herbicides in environmental samples.
Assuntos
Grafite/química , Herbicidas/isolamento & purificação , Fenoxiacetatos/isolamento & purificação , Extração em Fase Sólida/métodos , Poluentes Químicos da Água/isolamento & purificação , 1-Octanol/química , Eletroforese Capilar , Herbicidas/análise , Herbicidas/química , Concentração de Íons de Hidrogênio , Membranas Artificiais , Fenoxiacetatos/análise , Fenoxiacetatos/química , Reprodutibilidade dos Testes , Projetos de Pesquisa , Rios/química , Poluentes Químicos da Água/análise , Poluentes Químicos da Água/químicaRESUMO
This paper describes the preparation of new Pb(II)-imprinted polymeric particles using 2-vinylpyridine as a functional monomer, ethylene glycol dimethacrylate as the cross-linker, 2,2'- azobisisobutyronitrile as the initiator, diphenylcarbazone as the ligand, acetonitril as the solvent, and Pb(NO(3))(2) as the template ion, through bulk polymerisation technique. The imprinted lead ions were removed from the polymeric matrix using 5 mL of HCl (2 mol.L(-1)) as the eluting solvent. The lead ion concentration was determined by flame atomic absorption spectrometry. Optimum pH for maximum sorption was obtained at 6.0. Sorption and desorption of Pb(II) ions on the IIP particles were quite fast and achieved fully over 5 min. In the proposed method, the maximum sorbent capacity of the ion-imprinted polymer was calculated to be 75.4 mg g(-1). The preconcentration factor, relative standard deviation, and limit of detection of the method were found to be 245, 2.1%, and 0.42 ng mL(-1), respectively. The prepared ion-imprinted polymer particles have an increased selectivity toward Pb(II) ions over a range of competing metal ions with the same charge and similar ionic radius. This ion-imprinted polymer is an efficient solid phase for extraction and preconcentration of lead ions in complex matrixes. For proving that the proposed method is reliable, a wide range of food samples with different and complex matrixes was used.
Assuntos
Contaminação de Alimentos/análise , Chumbo/isolamento & purificação , Nanoestruturas/química , Oryza/química , Polímeros/química , Alimentos Marinhos/análise , Extração em Fase Sólida/métodos , Verduras/química , Adsorção , Animais , Peixes , Chumbo/química , Impressão Molecular , Polímeros/síntese química , Extração em Fase Sólida/instrumentação , Espectrofotometria AtômicaRESUMO
A novel electrochemical sensor based on Au-SH-SiO2 nanoparticles supported on metal-organic framework (Au-SH-SiO2@Cu-MOF) has been developed for electrocatalytic oxidation and determination of L-cysteine. The Au-SH-SiO2@Cu-MOF was characterized by scanning electron microscopy, transmission electron microscopy, x-ray diffraction and cyclic voltammetry. The electrochemical behavior of L-cysteine at the Au-SH-SiO2@Cu-MOF was investigated by cyclic voltammetry. The Au-SH-SiO2@Cu-MOF showed a very efficient electrocatalytic activity for the oxidation of L-cysteine in 0.1 M phosphate buffer solution (pH 5.0). The oxidation overpotentials of L-cysteine decreased significantly and their oxidation peak currents increased dramatically at Au-SH-SiO2@Cu-MOF. The potential utility of the sensor was demonstrated by applying it to the analytical determination of L-cysteine concentration. The results showed that the electrocatalytic current increased linearly with the L-cysteine concentration in the range of 0.02-300 µM and the detection limit was 0.008 µM. Finally, the sensor was applied to determine L-cysteine in water and biological samples.
Assuntos
Técnicas Biossensoriais/métodos , Cisteína/isolamento & purificação , Nanopartículas Metálicas/química , Cisteína/química , Técnicas Eletroquímicas , Ouro/química , Humanos , Limite de Detecção , Microscopia Eletrônica de Varredura , Microscopia Eletrônica de Transmissão , OxirreduçãoRESUMO
This paper describes the synthesis and application of novel magnetic metal-organic framework (MOF) [(Fe(3)O(4)-Pyridine)/Cu(3)(BTC)(2)] for preconcentration of Pd(II) and its determination by flame atomic absorption spectrometry (FAAS). A Box-Behnken design was used to find the optimum conditions for the preconcentration procedure through response surface methodology. Three variables including amount of magnetic MOF, extraction time, and pH of extraction were selected as factors for adsorption step, and in desorption step, four parameters including type, volume, and concentration of eluent, and desorption time were selected in the optimization study. These values were 30 mg, 6 min, 6.9, K(2)SO(4)+NaOH, 6 mL, 9.5 (w/v %)+0.01 mol L(-1), 15.5 min, for amount of MOF, extraction time, pH of extraction, type, volume, and concentration of the eluent, and desorption time, respectively. The preconcentration factor (PF), relative standard deviation (RSD), limit of detection (LOD), and adsorption capacity of the method were found to be 208, 2.1%, 0.37 ng mL(-1), and 105.1 mg g(-1), respectively. It was found that the magnetic MOF has more capacity compared to Fe(3)O(4)-Py. Finally, the magnetic MOF was successfully applied for rapid extraction of trace amounts of Pd (II) ions in fish, sediment, soil, and water samples.
RESUMO
The electrochemical behavior of raloxifene (RLX) on the surface of a glassy carbon electrode (GCE) has been studied by cyclic voltammetry (CV). The CV studies were performed in various supporting electrolytes, wide range of potential scan rates, and pHs. The results showed an adsorption-controlled and quasi-reversible process for the electrochemical reaction of RLX, and a probable redox mechanism was suggested. Under the optimum conditions, differential pulse voltammetry (DPV) was applied for quantitative determination of the RLX in pharmaceutical formulations. The DPV measurements showed that the anodic peak current of the RLX was linear to its concentration in the range of 0.2-50.0µM with a detection limit of 0.0750µM, relative standard deviation (RSD %) below 3.0%, and a good sensitivity. The proposed method was successfully applied for determination of the RLX in pharmaceutical and human plasma samples with a good selectivity and suitable recovery.
Assuntos
Análise Química do Sangue/métodos , Carbono/química , Eletroquímica/métodos , Vidro/química , Cloridrato de Raloxifeno/análise , Análise Química do Sangue/instrumentação , Química Farmacêutica , Eletroquímica/instrumentação , Eletrodos , Humanos , Limite de Detecção , Cloridrato de Raloxifeno/sangue , Cloridrato de Raloxifeno/química , Fatores de TempoRESUMO
A novel sorbent for simultaneous separation of cadmium and copper was prepared by functionalizing SBA-15 nanoporous silica with diphenylcarbazide. A solid-phase extraction method using the above sorbent has been developed to separate and concentrate trace amount of cadmium and copper ions from environmental samples by flame atomic absorption spectrophotometry measurements. The optimum experimental conditions such as pH, flow rates, type and the smallest amount of eluent for elution of cadmium and copper ions, break through volume and effect of coexisting ions on the separation and determination of cadmium and copper ions were evaluated. The extraction efficiency for cadmium and copper ions were greater than 98% and limit of detection (LOD) was 0.15 and 0.45 ng mL(-1) for cadmium and copper, respectively. The preconcentration factor was 294 and 291 for cadmium and copper, respectively, and the relative standard deviation (RSD) of the method was <4% for 10 separate column experiments for the determination of 5.0 µg cadmium and copper ions. The adsorption capacity of the nanoporous silica was 198 mg g(-1) for cadmium and 105 mg g(-1) for copper on functionalized SBA-15 nanoporous silica. Validation of the outlined method was performed by analyzing certified reference materials (Soil (NCS DC 73323) and ore polymetallic gold Zidarovo-PMZrZ (206 BG 326)). The practical applicability of the developed sorbent was examined using real samples such as sea water, fish and sediment samples.