Exploring potentialities of the HR-CS FAAS technique in the determination of Ni and Pb in mineral waters

National Health Surveillance Agency (ANVISA) established in the decree number 54 maximum allowed levels for Ni and Pb in mineral and natural waters at 20 µg L-1 and 10 µg L-1, respectively. For screening analysis purposes, the high-resolution continuum source flame atomic absorption spectrometry technique (HR-CS FAAS) was evaluated for the fast-sequential determination of nickel and lead in mineral waters.Two atomic lines for Ni (232.003 nm - main and 341.477 nm - secondary) and Pb (217.0005 nm - main and 283.306 nm - secondary) at different wavelength integrated absorbance (number of pixels) were evaluated. Sensitivity enhanced with the increase of the number of pixels and with the summation of the atomic lines absorbances. The main figures of merit associated to the HR-CS FAAS technique were compared with that obtained by line-source flame atomic absorption spectrometry (LS FAAS). Water samples were pre-concentrated about 5-fold by evaporation before analysis. Recoveries of Pb significantly varied with increased wavelength integrated absorbance. Better recoveries (92-93%) were observed for higher number of pixels at the main line or summating the atomic lines (90-92%). This influence was irrelevant for Ni, and recoveries in the 92-104% range were obtained in all situations.

Different lubricating oil treatments for the determination of Cu, Cr, Fe, Ni, Sb, Pb, and Zn by HR-CS FAAS

Microwave-assisted acid decomposition, direct dilution in kerosene, and oil-in-water emulsion were evaluated as lubricating oil pretreatment procedures for Cu, Cr, Fe, Ni, Pb, Sb, and Zn determination by High-Resolution Continuum Source Flame Atomic Absorption Spectrometry (HR-CS FAAS). For wet digestion, results were compared with those obtained by Flame Atomic Absorption Spectrometry (FAAS). The ultrasound probe used in emulsions sonication contaminated samples with Cr, although better results have been observed for the other six elements in this condition. In general, recovery percentages ranging from 81-106%(Cu), 80-107%(Cr), 85-114%(Fe), 82-116%(Ni), 86-117%(Pb), 85-115%(Sb), and 81-114%(Zn) were obtained. The HR-CS FAAS showed to be faster and more sensitive than FAAS.

Exploring potentialities of the HR-CS FAAS technique in the determination of Ni and Pb in mineral waters

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

A simple method based on HR-CS FAAS for multi-element determination of Cu, Fe, Mn and Zn in medicinal plants

A simple method to determine Cu, Fe, Mn and Zn in single aliquots of medicinal plants by HR-CS FAAS is proposed. The main lines for Cu, Mn and Zn, and the alternate line measured at the wing of the main line for Fe at 248.327 nm allowed calibration within the 0.025 - 2.0 mg L-1 Cu, 1.0 - 20.0 mg L-1 Fe, 0.05 - 2.0 mg L-1 Mn, 0.025 - 0.75 mg L-1 Zn ranges. Nineteen medicinal plants and two certified plant reference materials were analyzed. Results were in agreement at a 95% confidence level (paired t-test) with reference values. Limits of detection were 0.12 μg L-1 Cu, 330 μg L-1 Fe, 1.42 μg L-1 Mn and 8.12 μg L-1 Zn. Relative standard deviations (n=12) were ≤ 3% for all analytes. Recoveries in the 89 - 105% (Cu), 95 - 108% (Fe), 94 - 107% (Mn), and 93 - 110% (Zn) ranges were obtained.

Evaluation of Lubricating Oil Preparation Procedures for the Determination of Al, Ba, Mo, Si and V by High-Resolution Continuum Source FAAS

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Determinação de CD, PB, e TL em água produzida por HR-CS GF AAS após extração em ponto nuvem

Produced water is a major problem associated with the crude oil extraction activity. The monitoring of the levels of metals in the waste is constant and requires the use of sensitive analytical techniques. However, the determination of trace elements can often require a pre-concentration step. The objective of this study was to develop a simple and rapid analytical method for the extraction and pre-concentration based on extraction phenomenon cloud point for the determination of Cd, Pb and Tl in produced water samples by spectrometry of high resolution Absorption source continues and atomization graphite furnace. The Box Behnken design was used to obtain the optimal condition of extraction of analytes. The factors were evaluated: concentration of complexing agent (o,o-dietilditilfosfato ammonium, DDTP), the concentration of hydrochloric acid and concentration of surfactant (Triton X -114). The optimal condition obtained through extraction was: 0,6% m v-1 DDTP, HCl 0,3 mol L-1 and 0,2% m v-1 of Triton X - 114 for Pb; 0,7% m v-1 DDTP, HCl 0,8 mol L-1 and 0,2% m v-1 Triton X-114 for Cd. For Tl was evidenced that best extraction condition occurs with no DDTP, the extraction conditions were HCl 1,0 mol L-1 e 1,0% m v-1 de Triton X - 114. The limits of detection for the proposed method were 0,005 µg L-1 , 0,03 µg L-1 and 0,09 µg L-1 to Cd, Pb and Tl, Respectively. Enrichment factors Were greater than 10 times. The method was applied to the water produced in the Potiguar basin, and addition and recovery tests were performed, and values were between 81% and 120%. The precision was expressed with relative standard deviation (RSD) is less than 5%

Desenvolvimento de metodologia de extração e pré-concentração utilizando sistema microemulsionado para determinação de Cd, Co, Cu, Ni, Pb e Tl em águas naturais e produzidas por HR-CS AAS

The determination and monitoring of metallic contaminants in water is a task that must be continuous, leading to the importance of the development, modification and optimization of analytical methodologies capab le of determining the various metal contaminants in natural environments, because, in many cases, the ava ilable instrumentation does not provide enough sensibility for the determination of trace values . In this study, a method of extraction and pre- concentration using a microemulsion system with in the Winsor II equilibrium was tested and optimized for the determination of Co, Cd, P b, Tl, Cu and Ni through the technique of high- resolution atomic absorption spectrometry using a continuum source (HR-CS AAS). The optimization of the temperature program for the graphite furnace (HR-CS AAS GF) was performed through the pyrolysis and atomization curves for the analytes Cd, Pb, Co and Tl with and without the use of different chemical modifiers. Cu and Ni we re analyzed by flame atomization (HR-CS F AAS) after pre-concentr ation, having the sample introduction system optimized for the realization of discrete sampling. Salinity and pH levels were also analyzed as influencing factors in the efficiency of the extraction. As final numbers, 6 g L -1 of Na (as NaCl) and 1% of HNO 3 (v/v) were defined. For the determination of the optimum extraction point, a centroid-simplex statistical plan was a pplied, having chosen as the optimum points of extraction for all of the analytes, the follo wing proportions: 70% aqueous phase, 10% oil phase and 20% co-surfactant/surfactant (C/S = 4). After extraction, the metals were determined and the merit figures obtained for the proposed method were: LOD 0,09, 0,01, 0,06, 0,05, 0,6 and 1,5 μg L -1 for Pb, Cd, Tl, Co, Cu and Ni, re spectively. Line ar ranges of ,1- 2,0 μg L -1 for Pb, 0,01-2,0 μg L -1 for Cd, 1,0 - 20 μg L -1 for Tl, 0,1-5,0 μg L -1 for Co, 2-200 μg L -1 and for Cu e Ni 5-200 μg L -1 were obtained. The enrichment factors obtained ranged between 6 and 19. Recovery testing with the certified sample show ed recovery values (n = 3, certified values) after extraction of 105 and 101, 100 and 104% for Pb, Cd, Cu and Ni respectively. Samples of sweet waters of lake Jiqui, saline water from Potengi river and water produced from the oil industry (PETROBRAS) were spiked and the recovery (n = 3) for the analytes were between 80 and 112% confirming th at the proposed method can be used in the extraction. The proposed method enabled the sepa ration of metals from complex matrices, and with good pre-concentration factor, consistent with the MPV (allowed limits) compared to CONAMA Resolution No. 357/2005 which regulat es the quality of fresh surface water, brackish and saline water in Brazil.

Intra- and interspecific mineral composition variability of commercial instant coffees and coffee substitutes: contribution to mineral intake

The present paper reports the amount and estimated daily mineral intake of nine elements (Ca, Mg, K, Na, P, Fe, Mn, Cr and Ni) in commercial instant coffees and coffee substitutes (n = 49). Elements were quantified by high-resolution continuum source flame (HR-CS-FAAS) and graphite furnace (HR-CS-GFAAS) atomic absorption spectrometry, while phosphorous was evaluated by a standard vanadomolybdophosphoric acid colorimetric method. Instant coffees and coffee substitutes are rich in K, Mg and P (>100 mg/100 g dw), contain Na, Ca and Fe in moderate amounts (>1 mg/100 g), and trace levels of Cr and Ni. Among the samples analysed, plain instant coffees are richer in minerals (p < 0.001), except for Na and Cr. Blends of coffee substitutes (barley, malt, chicory and rye) with coffee (20–66%) present intermediate amounts, while lower quantities are found in substitutes without coffee, particularly in barley. From a nutritional point of view the results indicate that the mean ingestion of two instant beverages per day (total of 4 g instant powder), either with or without coffee, cannot be regarded as important sources of minerals to the human diet, although providing a supplementation of some minerals, particularly Mg and Mn in instant coffees. Additionally, and for authentication purposes, the correlations observed between some elements and the coffee percentage in the blends, with particular significance for Mg amounts, provides a potential tool for the estimation of coffee in substitute blends.

Quantificação de metais potencialmente tóxicos em mexilhão dourado (Limnoperna fortunei) por espectrometria de absorção atômica com fonte contínua e alta resolução empregando amostragem direta de sólidos

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Determination of copper at wide range concentrations using instrumental features of high-resolution continuum source flame atomic absorption spectrometry

This work describes a method to determine Cu at wide range concentrations in a single run without need of further dilutions employing high-resolution continuum source flame atomic absorption spectrometry. Different atomic lines for Cu at 324.754 nm, 327.396 nm, 222.570 nm, 249.215 nm and 224.426 nm were evaluated and main figures of merit established. Absorbance measurements at 324.754 nm, 249.215 nm and 224.426 nm allows the determination of Cu in the 0.07 - 5.0 mg L-1, 5.0 - 100 mg L-1 and 100 - 800 mg L-1 concentration intervals respectively with linear correlation coefficients better than 0.998. Limits of detection were 21 µg L-1, 310 µg L-1 and 1400 µg L-1 for 324.754 nm, 249.215 nm and 224.426 nm, respectively and relative standard deviations (n = 12) were £ 2.7%. The proposed method was applied to water samples spiked with Cu and the results were in agreement at a 95% of confidence level (paired t-test) with those obtained by line-source flame atomic absorption spectrometry.

Determination of macro- and micronutrients in plant leaves by high-resolution continuum source flame atomic absorption spectrometry combining instrumental and sample preparation strategies

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Determination of Zinc in Lubricating Oil by Flame MS Employing Ultrasonic Extraction

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Evaluation of alternate lines of Fe for sequential multi-element determination of Cu, Fe, Mn and Zn in soil extracts by high-resolution continuum source flame atomic absorption spectrometry

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Internal standardization combined with dilute-and-shoot preparation of distilled alcoholic beverages for Cu determination by high-resolution continuum source flame atomic absorption spectrometry

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Determination of copper at wide range concentrations using instrumental features of high-resolution continuum source flame atomic absorption spectrometry

This work describes a method to determine Cu at wide range concentrations in a single run without need of further dilutions employing high-resolution continuum source flame atomic absorption spectrometry. Different atomic lines for Cu at 324. 754 nm, 327. 396 nm, 222. 570 nm, 249. 215 nm and 224. 426 nm were evaluated and main figures of merit established. Absorbance measurements at 324. 754 nm, 249. 215 nm and 224. 426 nm allows the determination of Cu in the 0. 07-5. 0 mg L -1, 5. 0-100 mg L -1 and 100-800 mg L -1 concentration intervals respectively with linear correlation coefficients better than 0. 998. Limits of detection were 21 μg L -1, 310 μg L -1 and 1400 μg L -1 for 324. 754 nm, 249. 215 nm and 224. 426 nm, respectively and relative standard deviations (n = 12) were ≤ 2. 7%. The proposed method was applied to water samples spiked with Cu and the results were in agreement at a 95% of confidence level (paired t-test) with those obtained by line-source flame atomic absorption spectrometry.