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1.
Food Chem ; 334: 127559, 2021 Jan 01.
Artigo em Inglês | MEDLINE | ID: mdl-32711270

RESUMO

This study approaches the development of a method for the determination of Ca, Mg, Zn, and Fe in liquid and powdered cow milk. The method is based on sample dissolution assisted by ultrasound energy in tetramethylammonium hydroxide (TMAH) media and determination by flame atomic absorption spectrometry (FAAS). Central composite design (CCD) associated with response surface methodology and desirability function allowed the fast and efficient optimization of the variables involved in the performance of the dissolution. The developed dissolution method allowed Ca, Fe, Zn, and Mg determination in milk samples with adequate analytical characteristics for these determinations. Addition/recovery tests and analysis of a certified reference material of skimmed powdered milk (ERM-BD150) have shown that this method presents enough accuracy to carry out these analyses.


Assuntos
Análise de Alimentos/métodos , Metais/análise , Leite/química , Compostos de Amônio Quaternário/química , Espectrofotometria Atômica/métodos , Animais , Bovinos , Feminino , Análise de Alimentos/estatística & dados numéricos , Análise Multivariada , Pós , Solubilidade
2.
Zhonghua Lao Dong Wei Sheng Zhi Ye Bing Za Zhi ; 38(10): 767-769, 2020 Oct 20.
Artigo em Chinês | MEDLINE | ID: mdl-33142384

RESUMO

Objective: To set up a new method to determine the nickel of urine in urine using dispersive liquid-liquid microextraction (DLLME) coupled with graphite furnace atomic absorption spectrometry (GFAAS) . Methods: From September 2018 to September 2019, the methanol, pyrrolidine dithiocarbamate and ionic liquid 1-hexyl-3-methyl-imidazolium hexafluorophosphate were used as dispersive solvent, the chelating agent and extraction solvent for the preconcentration of nickel, respectively. After adding into buffer solution of pH 9, ultrasonic dissolving for 10 minutes, centrifugal separation and then discarding the supernatant, the precipitate was saved. Dissolving the precipitate by methanol, mixing thoroughly on a vortex mixer, the 15 µl of the mixed solution was used for determination by graphite furnace atomic absorption spectrometry. Results: The linear correlation coefficient of urine nickel concentration in the range of 2.0-10.0 µg/L, r=0.999, with the detection limitation of 0.43 µg/L. The recovery rate and the relative standard deviations were 95.6%-103.7% and 2.53%-4.82%, respectively. Conclusion: The method, which has low detection limit, high recovery rate and good precision, is suitable for the determination of nickel in urine for the occupational populations exposure to nickel and non-occupational exposure.


Assuntos
Grafite , Líquidos Iônicos , Limite de Detecção , Níquel , Espectrofotometria Atômica , Ultrassom
3.
Chemosphere ; 261: 128128, 2020 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-33113644

RESUMO

There is an increased production and demand for ewes' milk in the Republic of Croatia, as well as globally. There is also a growing concern about its quality, since milk from farm animals may become contaminated with mercury and other toxic elements. Thus, the aim of this paper is to determine the influence of lactation stage on the ewes' milk quality in western Croatia by considering concentrations of mercury and other elements in ewes' milk. The research was conducted on 36 Travnik pramenka sheep during different lactation stages. The digested milk samples were analysed with continuous flow hydride generation technique by using inductively coupled plasma mass spectrometry. Samples were taken during 40th, 80th and 120th d of lactation. Yield and quality of ewes' milk was within lactation curve. As lactation progressed, significantly lower concentrations of Hg (on 80th d compared to 40th d) and of Cd (120th d compared to 80th d) were noted, and Hg on 120th d was below the detection limit. Concentrations of Ca and Cu were lower on the 120th d compared to 40th d, while P, Mg, Fe, Zn, Mn, and Se were lower on the 80th and 120th d compared to the 40th d. Concentrations of K, Mo, and Cr differed among all stages of lactation. Regarding toxic elements, the observed low concentrations of Hg, Co, Cd and As suggest that ewes' milk in western Croatia is safe for human or animal consumption.


Assuntos
Contaminação de Alimentos/análise , Lactação , Mercúrio/análise , Leite/química , Ovinos , Animais , Croácia , Feminino , Humanos , Espectrometria de Massas , Espectrofotometria Atômica , Fatores de Tempo
4.
Exp Parasitol ; 218: 107988, 2020 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-32890471

RESUMO

In the present work, we synthesized silver nanoparticles supported by rice husk by hydrothermal treatment, as-synthesized silver nanoparticles rice husk (AgNPs-RH) bio-composite mixed with potter clay thoroughly, molded, dried into a disc-shaped before firing and applying as a point of use larvicidal agent. As designed, porous terracotta disc (PTD) infused with AgNPs-RH-biocomposite were characterized by UV spectrophotometer, Fourier-transform infrared spectroscopy, transmission electron microscopy, X-ray diffraction analysis and energy-dispersive X-ray spectroscopy. The amount of silver ions released from the PTD was also found to be within the prescribed limit of 0.1 ppm-level. Later we dropped the PTD and tested its larvicidal activity against the IVth instar larva stage of Aedes, Anopheles and Culex species. We found 100% larvicidal mortality in 24 h of exposure to the designed PTD and the amount of silver released from the porous disc was found to be 0.0343 ppm. Further from the histopathological studies of dead larvae revealed that the silver ions from the PTD have substantially damaged the exoskeleton of larvae.


Assuntos
Aedes , Anopheles , Culex , Nanopartículas Metálicas/normas , Controle de Mosquitos/instrumentação , Animais , Ecossistema , Química Verde , Larva , Nanopartículas Metálicas/economia , Nanopartículas Metálicas/provisão & distribução , Microscopia Eletrônica de Transmissão , Controle de Mosquitos/economia , Oryza , Prata , Espectrometria por Raios X , Espectrofotometria Atômica , Espectrofotometria Ultravioleta , Espectroscopia de Infravermelho com Transformada de Fourier , Difração de Raios X
5.
Environ Monit Assess ; 192(9): 583, 2020 Aug 15.
Artigo em Inglês | MEDLINE | ID: mdl-32803620

RESUMO

In this study, a new analytical strategy was developed to determine trace cadmium in aqueous samples with high sensitivity and accuracy. A combination of magnetic nickel nanoparticles (Ni-MNPs) based dispersive solid-phase extraction (DSPE) and flame atomic absorption spectrometry fitted with a slotted quartz tube (SQT-FAAS) lowered the detection limit of cadmium. The magnetic Ni nanoparticles were synthesized, characterized, and thoroughly optimized in a stepwise approach. The quartz tube was custom cut in the laboratory to suit the specifics of the flame burner. Using the optimized conditions, a limit of detection value of 0.58 µg/L and limit of quantification value of 1.93 µg/L were obtained. To demonstrate accuracy and applicability of the developed method, well water samples were analyzed for their Cd content, and matrix effect on the extraction yield was investigated. The percent recovery results calculated ranged from 93.8 to 108.2%, with corresponding standard deviation values ranging from 1.7 to 7.7. These results established the developed method as sensitive, accurate, and precise for determination of cadmium at trace levels.


Assuntos
Microextração em Fase Líquida , Poluentes Químicos da Água/análise , Cádmio/análise , Monitoramento Ambiental , Fenômenos Magnéticos , Quartzo , Extração em Fase Sólida , Espectrofotometria Atômica
6.
J Environ Sci Health B ; 55(10): 889-897, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32666867

RESUMO

The Animas River Watershed has long received discharges of naturally occurring acid rock drainage; however, on August 5, 2015, three million gallons flowed into the agricultural region of Farmington, New Mexico and the Navajo Nation. Consumers and growers in the region were fearful that produce might absorb heavy metals from contaminated irrigation water originating from these rivers. Samples were collected from the region including corn (n = 30), pumpkin (n = 10), squash (n = 10), and cucumber (n = 10) then processed and tested using inductively coupled plasma-optical emission spectrometry (ICP-OES) for concentrations of nine metals of interest. These include toxic metals: Al, As, and Pb, which were compared to the World Health Organization limits, 18.29 mg d-1, 0.192 mg d-1, and 0.05 mg kg-1, respectively and essential metals: Cr, Fe, Mn, Zn, Ca, and Cu whose levels were compared to the National Academies' dietary references for tolerable upper intake levels. Results indicate that produce grown in the region contained significantly less metal than the allowable limits, except for Pb in two corn samples. This research is the first attempt to monitor and analyze heavy metal absorption of produce in the area.


Assuntos
Irrigação Agrícola , Produtos Agrícolas/química , Monitoramento Ambiental , Metais Pesados/análise , Poluentes Químicos da Água/análise , Cucumis sativus/química , Cucurbita/química , New Mexico , Espectrofotometria Atômica , Zea mays/química
7.
J Chromatogr A ; 1624: 461219, 2020 Aug 02.
Artigo em Inglês | MEDLINE | ID: mdl-32540068

RESUMO

The alpha-emitter 225Ac (t1/2 = 9.92 d) is currently under development for targeted alpha-particle therapy of cancer, and accelerator production of 225Ac via proton irradiation of thorium targets requires robust separations of 225Ac from chemically similar fission product lanthanides. Additionally, the lanthanide elements represent critical components in modern technologies, and radiolanthanides such as 140Nd (t1/2 = 3.37 d) also have potential application in the field of nuclear medicine. The ionic liquid, 1-butyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide ([Bmim][NTf2]), combined with the diglycolamide extractant, N,N-dioctyldiglycolamic acid (DODGAA), was adsorbed on macroporous resin support to produce a solvent impregnated resin (SIR) that was investigated for separations of 225Ac and lanthanides. The equilibrium distribution coefficients (Kd) of the rare earth elements (Sc(III), Y(III), Ln(III)), 225Ac(III), Th(IV), and U(VI) on the prepared DODGAA/[Bmim][NTf2]-SIR were determined from batch adsorption experiments in HCl and HNO3 media. The DODGAA/[Bmim][NTf2]-SIR exhibited preferential uptake of the heavier lanthanide elements while allowing for the separation of the lighter lanthanides. Column separations utilizing the DODGAA/[Bmim][NTf2]-SIR were effective at separating the lighter lanthanides from each other, and separating 225Ac from a mixture of lanthanides, 213Bi, and 225Ra without the need for additional complexing agents.


Assuntos
Actínio/isolamento & purificação , Cromatografia por Troca Iônica/métodos , Glicolatos/química , Imidazóis/química , Elementos da Série dos Lantanídeos/química , Líquidos Iônicos/química , Elementos da Série dos Lantanídeos/isolamento & purificação , Porosidade , Solventes/química , Espectrofotometria Atômica
8.
Food Chem ; 328: 127124, 2020 Oct 30.
Artigo em Inglês | MEDLINE | ID: mdl-32485585

RESUMO

This work demonstrates the challenges for selenium (Se) determination in bean samples using high-resolution continuum source Graphite Furnace Atomic Absorption Spectrometry (HR-CS-GF-AAS) and line source Graphite Furnace Atomic Absorption Spectrometry (LS-GF-AAS). Different chemical modifiers were optimized namely; Ir, Ru, and Pd/Mg nitrates. At selenium contents <5 ng g-1, it cannot be quantified accurately. Spectral interferences of the molecular bands of PO and NO as well as the iron lines with Se line at 196.026 were demonstrated. The noticeable low energy of the continuum source of the HR-CS-GF-AAS at 196.026 nm gives high values of the limits of detection and quantification. The Se limits of detection were found to be 24, 33, and 29 ng g-1 for Ir, Ru, and Pd/Mg modifiers, respectively. In situ trapping hydride generation LS-GF-AAS gives better limits of detection and it reached 30 pg g-1 with Ir modifier.


Assuntos
Fabaceae/química , Selênio/análise , Grafite/química , Ferro/química , Espectrofotometria Atômica
9.
Food Chem ; 329: 127210, 2020 Nov 01.
Artigo em Inglês | MEDLINE | ID: mdl-32512388

RESUMO

In this study, a novel, easy, rapid and green zirconium nanoparticles (Zr-NPs) based dispersive solid phase extraction (DSPE) method is presented for the precise and sensitive determination of selenium by slotted quartz tube-flame atomic absorption spectrophotometry (SQT-FAAS). Influential parameters of the extraction procedure were optimized by altering one parameter while keeping the other parameters constant. The optimum conditions were selected as 10 mg of Zr-NPs, 75 s vortex period, and 200 µL of concentrated HCl for 30 mL of sample/standard solution. The linear range of the developed method was found to be between 25 and 100 µg/L, and the respective limits of detection and quantification were 5.3 and 18 µg/L. About 415 folds enhancement in detection power was achieved by the optimized method relative to the conventional FAAS. Green tea samples were spiked and used for recovery experiments and the results obtained were between 92 and 102%.


Assuntos
Nanopartículas Metálicas/química , Selênio/análise , Espectrofotometria Atômica/métodos , Chá/química , Zircônio/química , Concentração de Íons de Hidrogênio , Limite de Detecção , Reprodutibilidade dos Testes , Selênio/isolamento & purificação , Extração em Fase Sólida
10.
Artigo em Inglês | MEDLINE | ID: mdl-32400283

RESUMO

This study aimed to evaluate the exposure to environmental lead (Pb) of children from a traditional community of African descent in Brazil and the effects on hematological parameters. Children (n = 75) aged 5.5-13 years from the exposed areas classified as low (LEx) and moderately (MEx) exposed were compared with children (n = 75) of a control group (CG). Dust Pb loading rates (RtPbs) at children's homes were measured. Peripheral venous blood samples were collected to assess Pb biomarkers of exposure and effects. All Pb determinations were performed by graphite furnace atomic absorption spectrometry. The median (IQR) of RtPb, PbB level, and ALA-D activity were 65 (25-137) µgPb/m2/30 days, 1.0 (0.1-2.8) µg/dL, and 71 (55-86) U/L, respectively. Spearman correlation evidenced the relationship of PbB with RtPb (rho = 0.368, P < 0.001) and ALA-D activity (rho = -0.587; P ˂ 0.001). After adjusting for exposure degree and child's age, a decline of 7.4 U/L in ALA-D activity was associated with a 10-fold increase in PbB. The prevalence ratio of elevated PbB (>5 µg/dL) in LEx and MEx areas were 1.5 and 3.7, respectively. Indoor dust exposure, living near pottery workshops and the secondary exposure were the main determinants of elevated PbB levels, which were associated with hematological effects.


Assuntos
Grupo com Ancestrais do Continente Africano , Indústria Química , Poeira/análise , Exposição Ambiental/análise , Poluentes Ambientais/sangue , Chumbo/sangue , Adolescente , Biomarcadores/sangue , Brasil , Cerâmica , Criança , Pré-Escolar , Estudos Transversais , Exposição Ambiental/efeitos adversos , Feminino , Humanos , Ferro/metabolismo , Masculino , Prevalência , Fatores Socioeconômicos , Espectrofotometria Atômica
11.
PLoS One ; 15(5): e0233357, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32433650

RESUMO

Trace elements and minerals are compounds that are essential for the support of a variety of biological functions and play an important role in the formation of and the defense against oxidative stress. Here we describe a technique, allowing sequential detection of the trace elements (K, Zn, Se, Cu, Mn, Fe, Mg) in serum and whole blood by an ICP-MS method using single work-up, which is a simple, quick and robust method for the sequential measurement and quantification of the trace elements Sodium (Na), Potassium (K), Calcium (Ca), Zinc (Zn), Selenium (Se), Copper (Cu), Iron (Fe), Manganese (Mn) and Magnesium (Mg) in whole blood as well as Copper (Cu), Selenium (Se), Zinc (Zn), Iron (Fe), Magnesium (Mg), Manganese (Mn), Chromium (Cr), Nickel (Ni), Gold (Au) and Lithium (Li) in human serum. For analysis, only 100 µl of serum or whole blood is sufficient, which make this method suitable for detecting trace element deficiency or excess in newborns and infants. All samples were processed and analyzed by ICP-MS (Agilent Technologies). The accuracy, precision, linearity and the limit of quantification (LOQ), Limit of Blank (LOB) and the limit of detection (LOD) of the method were assessed. Recovery rates were between 80-130% for most of the analyzed elements; repeatabilities (Cv %) calculated were below 15% for most of the measured elements. The validity of the proposed methodology was assessed by analyzing a certified human serum and whole blood material with known concentrations for all elements; the method described is ready for routine use in biomonitoring studies.


Assuntos
Espectrofotometria Atômica/métodos , Espectrometria de Massas em Tandem/métodos , Oligoelementos/sangue , Cálcio/sangue , Cromo/sangue , Cobre/sangue , Ouro/sangue , Humanos , Ferro/sangue , Limite de Detecção , Lítio/sangue , Magnésio/sangue , Manganês/sangue , Níquel/sangue , Potássio/sangue , Selênio/sangue , Sódio/sangue , Zinco/sangue
12.
Artigo em Inglês | MEDLINE | ID: mdl-32290204

RESUMO

The levels and distribution of 9 trace elements in apples from two orchards in north-east (NE) Romania were measured by means of Atomic Absorption Spectroscopy (AAS) on 42 samples of 9 different apple varieties, with average content ranges of 0.909-4.458 mg·kg-1 Zn, 0.055-0.409 mg·kg-1 Cu, 0.700-2.476 mg·kg-1 Fe, 0.328-0.695 mg·kg-1 Mn, 0.054-0.257 mg·kg-1 Ni, 0.005-0.101 mg·kg-1 Cr, 0.027-0.420 mg·kg-1 Co, 0.413-1.149 mg·kg-1 Pb, and 0.025-0.127 mg·kg-1 Cd. For some apple varieties, Pb contents are 2 times higher than the maximum contents allowed according to national standards, Cd contents are 6 times higher, and in some cases Zn contents also exceed the national threshold, showing preferential accumulation on specific apple varieties. Whilst some research has been carried out on trace element distribution in apples, this study assessed the areal distribution of toxic trace elements in connection to the adjacent roads. The first apple orchard is located near a county road, with reduced car traffic, while the second orchard shares its southern limit with a high-volume traffic road (E583). The results point towards a proportional increase of Pb and, to some extent, of Cd in the samples close to the E583 road in contrast with the other orchard, where no such observation derived. Along the areal distribution of the selected elements, the preferential accumulation of dietary recommended trace elements in different apple varieties was assessed. In matters of daily nutrients content in trace elements, the best sources of Fe, Cu, and Zn in terms of apple varieties are Golden Delicious, Jonathan, and Kaltherer Böhmer.


Assuntos
Malus , Romênia , Espectrofotometria Atômica , Oligoelementos/análise
13.
Arch Environ Contam Toxicol ; 79(1): 147-155, 2020 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-32270210

RESUMO

Mercury is a heavy metal that has caused concern regarding the health of fish and of those who consume them. In this research, the concentrations of mercury in the muscle tissues of zander and European perch from Anzali were measured using a graphite furnace atomic absorption spectrometer (GFAAS). The average concentrations of mercury in the muscle of the zander and European perch were 244 and 105 µg/kg dry weight, respectively. A nonsignificant positive correlation between morphological parameters and mercury values was observed for both species (P > 0.05). The concentrations of mercury accumulated in the two fish species were lower than the values recorded in most similar studies, and were below the permissible limit provided by the National Iranian Standards Organization, FAO, WHO, US EPA, EC, and US FDA. In addition, the HQ value was less than one. Therefore, in general, this research indicates that exposure to mercury does not threaten the health of these species and their consumers.


Assuntos
Contaminação de Alimentos/análise , Mercúrio/análise , Músculos/química , Percas/metabolismo , Poluentes Químicos da Água/análise , Animais , Mar Cáspio , Irã (Geográfico) , Espectrofotometria Atômica
14.
Food Chem ; 321: 126690, 2020 Aug 15.
Artigo em Inglês | MEDLINE | ID: mdl-32244139

RESUMO

The current research article was reported the synthesis of a novel poly(3-hydroxy butyrate)-b-poly(vinyl benzyl xanthate) block copolymer (PHB-Xa) for vortex-assisted solid-phase microextraction of cobalt(II) and nickel(II) from canned foodstuffs prior to their determinations by flame atomic absorption spectrometry. The block copolymer was synthesized and characterized by nuclear magnetic resonance spectroscopy and Fourier transform infrared spectroscopy. Experimental variables affecting the extraction efficiency of the copolymer were optimized. Since the PHB-Xa block copolymers have a high π conjugate structure and hydrophobicity, the use of this adsorbent yielded quantitative results for the extraction of Ni(II) and Co(II). After optimization, the linearities for Ni(II) and Co(II) were 0.05-80 ng mL-1 and 0.2-100 ng mL-1, respectively. The limits of detection and the limits of quantification were in the range of 0.015-0.06 ng mL-1 and 0.05-0.2 ng mL-1, respectively. The method was successfully applied to determination of Ni(II) and Co(II) in canned foodstuffs prepared by microwave digestion.


Assuntos
Cobalto/isolamento & purificação , Análise de Alimentos/métodos , Níquel/isolamento & purificação , Polímeros/química , Microextração em Fase Sólida/métodos , Cobalto/análise , Contaminação de Alimentos , Alimentos em Conserva , Hidroxibutiratos/química , Limite de Detecção , Espectroscopia de Ressonância Magnética , Níquel/análise , Poliésteres/química , Polímeros/síntese química , Cloreto de Polivinila/química , Espectrofotometria Atômica/métodos , Espectroscopia de Infravermelho com Transformada de Fourier
15.
Environ Sci Pollut Res Int ; 27(17): 21914-21923, 2020 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-32285391

RESUMO

In this work, some trace elements (As, Cd, Cr, Cu, and Pb) were determined for the first time in the crustacean Sergio mirim (Decapoda: Thalassinidea: Callianassidae) from Southern Coast (Rio Grande, RS) of Brazil. The trace element determination was carried out by graphite furnace atomic absorption spectrometry (GF AAS) and inductively coupled plasma mass spectrometry (ICP-MS). Different microwave radiation-based sample digestion methods were evaluated. The analyte concentration ranged from 1.45 to 3.70 µg g-1 for As, 0.615 to 0.942 µg g-1 for Cd, 0.884 to 7.20 µg g-1 for Cr, 122 to 275 µg g-1 for Cu, and 0.390 to 0.916 µg g-1 for Pb. The limits of quantification for As, Cd, Cr, Cu, and Pb were 0.12, 0.01, 0.16, 0.92, and 0.06 µg g-1, respectively. The accuracy was evaluated by results comparison between GF AAS and ICP-MS techniques, as well as by analysis of certified reference materials of fish muscle and oyster tissue, with agreement from 92 to 108%. The feasibility of using Sergio mirim as a promising environmental bioindicator candidate was evaluated, since that it is an abundant organism in the studied area (South cost of Brazil) as well as in other places around the world.


Assuntos
Decápodes , Oligoelementos/análise , Animais , Brasil , Alimentos Marinhos/análise , Espectrofotometria Atômica
16.
Food Chem ; 321: 126715, 2020 Aug 15.
Artigo em Inglês | MEDLINE | ID: mdl-32259733

RESUMO

Sample preparation methodsforcereal digestion were evaluated for the first time for subsequent As, Cd, Hg, and Pb determination by atomic absorption spectroscopy techniques. Microwave-assisted digestion (MW-AD) under high and medium pressure and microwave-induced combustion (MIC) were evaluated. The use of MIC made it possible to digest 700 mg of samples, and agreements of 97, 96, 100 and 92% were obtained for As, Cd, Hg and Pb, respectively, when 7 mol L-1 HNO3 was used as the absorbing solution. It was not necessary to dilute the digests obtained to avoid interferences in the quantification of As, Cd, Hg, and Pb. Although high pressure MW-AD was efficient for cereal digestion, interferences were observed on analyte determination. Limits of quantification obtained by MIC were 0.034 (As), 0.015 (Cd), 0.021 (Hg) and 0.105 (Pb) µg g-1, which are suitable to attain the maximum levels recommended by international agencies in cereal samples.


Assuntos
Arsênico/análise , Cádmio/análise , Grão Comestível/química , Chumbo/análise , Mercúrio/análise , Micro-Ondas , Espectrofotometria Atômica
17.
Artigo em Chinês | MEDLINE | ID: mdl-32306698

RESUMO

Objective: To establish a method for the determination of manganese in urine with graphite furnace atomic absorption spectrometry (GFAAS) by using ionic liquid microextraction. Methods: The ethanol, 8-hydroxyquinoline and ionic liquid 1-octyl-3-methyl-imidazolium hexafluorophosphate were used as dispersive solvent, chelating agent and extraction solvent respectively, for the preconcentration of manganese. After the optimal extraction conditions were optimized by single factor rotations, evaluate the performance indicators such as methodological precision, accuracy, and detection limit. Results: The linear range of urine manganese was 0.0-1.6 µg/L, and the correlation coefficient of standard curve line was 0.992, the detection limit was 0.03 µg/L, the recovery of sample spiked was 84.90%-96.50%, and the relative standard deviation was 0.36%-1.84%. Conclusion: The method has the advantages of low detection limit, high recovery rate and high sensitivity. It is suitable for the determination of manganese in urine samples from occupational exposure populations and the general population.


Assuntos
Microextração em Fase Líquida , Manganês/urina , Espectrofotometria Atômica , Grafite , Humanos , Limite de Detecção , Exposição Ocupacional/análise
18.
Artigo em Chinês | MEDLINE | ID: mdl-32306699

RESUMO

Objective: To instruct a method of determining thallium in the urine by graphite furnace atomic absorption spectrometry(GF-AAS) with colloidal palladium as the matrix modifier. Methods: Urine samples were first diluted and then determined by GF-AAS with colloidal palladium while using thermal sample injection. Results: The optimum volume of colloidal palladium was 6 µl and the best ashing temperature was 600-800 ℃ while the atomization temperature was 1700-1900 ℃ . This method showed a good linearity relationship when the concentration between 0.33 and 50.0 µg/L while the correlation coefficient of standard curve line was 0.9992, and the detection limit was 0.33 µg/L and the recovery rate was between 92.7% and 102.3% with the intra-day precision in the range of 2.55% to 3.66% and the inter-day precision in the range of 1.77% to 3.85%. Conclusion: This method has the advantages of low detect limit, high sensitivity and good precision, and it can be used in the biological monitoring and emergency detecting of workers exposed to thallium.


Assuntos
Tálio/urina , Protocolos de Quimioterapia Combinada Antineoplásica/análise , Ciclofosfamida/análise , Grafite , Humanos , Limite de Detecção , Lomustina/análise , Paládio , Espectrofotometria Atômica , Vincristina/análise
19.
Environ Monit Assess ; 192(5): 272, 2020 Apr 08.
Artigo em Inglês | MEDLINE | ID: mdl-32266579

RESUMO

In this study, switchable solvent (SS) for liquid-phase microextraction (LPME) was used as a tool to preconcentrate nickel from aqueous samples for determination by flame atomic absorption spectrometry. The SS-LPME method was optimized thoroughly to boost the absorbance signal of nickel for trace level determination. Parameters optimized included switchable solvent volume, sodium hydroxide concentration, sodium hydroxide volume, and eluent volume. The SS-LPME method enhanced the detection power by about 32-folds, and a slotted quartz tube (SQT) was used to obtain 2.6-folds increase in detection power. The combination of LPME and SQT-FAAS produced 104-folds enhancement, correlating to a limit of detection value of 1.8 µg/L. Low relative standard deviations calculated for the lowest calibration concentration indicated good repeatability for replicate measurements. Accuracy of the optimized method and its applicability to real samples was tested on two river samples. The results (85-103%) obtained from the spike recovery experiments were satisfactory.


Assuntos
Monitoramento Ambiental , Microextração em Fase Líquida , Níquel/análise , Poluentes Químicos da Água/análise , Quartzo , Solventes , Espectrofotometria Atômica
20.
Talanta ; 212: 120783, 2020 May 15.
Artigo em Inglês | MEDLINE | ID: mdl-32113546

RESUMO

A new procedure combining dispersive liquid-liquid microextraction and electrothermal atomic absorption spectrometry was proposed for the determination of molybdenum in plants and animal tissue. The optimized conditions for the microextraction procedure were: 150 µL of 0.3 mol L-1 potassium ethyl xanthate (pH 1.4) and 1000 µL of acetonitrile and 50 µL of carbon tetrachloride as dispersive and extractant solvent, respectively. A limit of detection of 0.03 µg kg-1 and a limit of quantification of 0.11 µg kg-1, as well as an enrichment factor of 200, were achieved employing this procedure. Standard reference materials were used for trueness and precision evaluation. No significant differences were found at the 95% confidence level between certified and obtained values, and the precision expressed as repeatability (sr %) was 4.1% for animal tissue and 4.7% for plant material. The method was successfully applied for the determination of Mo in bovine meat and pasture samples from different livestock establishments.


Assuntos
Microextração em Fase Líquida/métodos , Molibdênio/análise , Carne Vermelha/análise , Espectrofotometria Atômica/métodos , Animais , Bovinos , Quelantes/química , Festuca/química , Músculos Isquiossurais/química , Limite de Detecção , Molibdênio/química , Tionas/química
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