Ana Maria Pinto dos Santos

Simultaneous determination and speciation analysis of arsenic and chromium in iron supplements used for iron-deficiency anemia treatment by HPLC-ICP-MS

This work proposes the use of high performance liquid chromatography coupled to inductively coupled plasma mass spectrometry (HPLC-ICP-MS) for simultaneous speciation of arsenic and chromium in iron supplements used for the treatment of anemia. The sample preparation procedure recommended for the total determination of arsenic and chromium was established using acid digestion in a microwave assisted oven. For speciation analysis, however, the microwave-assisted extraction procedure involved the use of water as extraction solvent at 90°C for 30min. The chromatographic separation was performed using a mobile phase containing 1.0mM tetrabutylammonium hydroxide (TBAH), 0.7mM ethylenediaminetetraacetic acid (EDTA) and 5% methanol at pH 7.2. Helium was used in the collision cell for elimination of the interferences. Under optimized conditions, the separation and detection of the As(III), As(V), Cr(III) and Cr(VI) species can be performed in 5min, permitting their quantification with the external calibration technique with standards prepared in the mobile phase. The limits of quantification obtained were 0.008, 0.010, 0.5 and 0.14µgg-1, for As(III), As(V), Cr(III) and Cr(VI), respectively. The accuracy of the method was evaluated and confirmed by addition/recovery tests. The recoveries obtained varied from 81% to 110%. The proposed method was applied to the speciation analysis of arsenic and chromium in commercially available iron supplements acquired in several cities in Brazil and Spain. The content of the species ranged from 0.01 to 1.3µgg-1 for arsenic, and from 0.4 to 61.2µgg-1 for chromium.

Homogeneity study of a corn flour laboratory reference material candidate for inorganic analysis.

In this work, a homogeneity study of a corn flour reference material candidate for inorganic analysis is presented. Seven kilograms of corn flour were used to prepare the material, which was distributed among 100 bottles. The elements Ca, K, Mg, P, Zn, Cu, Fe, Mn and Mo were quantified by inductively coupled plasma optical emission spectrometry (ICP OES) after acid digestion procedure. The method accuracy was confirmed by analyzing the rice flour certified reference material, NIST 1568a. All results were evaluated by analysis of variance (ANOVA) and principal component analysis (PCA). In the study, a sample mass of 400mg was established as the minimum mass required for analysis, according to the PCA. The between-bottle test was performed by analyzing 9 bottles of the material. Subsamples of a single bottle were analyzed for the within-bottle test. No significant differences were observed for the results obtained through the application of both statistical methods. This fact demonstrates that the material is homogeneous for use as a laboratory reference material.

Determination of micro and macro elements in iron supplements used for treatment of anemia and evaluation employing chemometric analysis tools

This paper propose a method using inductively coupled plasma optical emission spectrometry (ICP OES) for the determination of Ca, K, Mg, Mn, Na, P and Zn in iron supplement used for the treatment of anemia and evaluation of the results by chemometric analysis tools, principal component analysis (PCA) and hierarchical cluster analysis (HCA). Sample preparation was performed by acid digestion using 3.0 mL of HNO3 and 1.0 mL of H2O2 (30% v/v). Limits of quantification (mg L−1) were 0.52 for Ca, 0.14 for K, 0.03 for Mg, 0.07 for Mn, 0.40 for Na, 0.36 for P and 0.24 for Zn, showing that the method is sensitive for the determination of elements. There is no certified reference material of ferrous supplement for evaluation of the accuracy. Thus, addition/recovery tests were performed to evaluate the accuracy of the method. The recovery values achieved varied from 89.75 to 114.97%, confirming the applicability of this method for quantification of the mentioned elements in these iron supplements. The method proposed was applied for determination of Ca, K, Mg, Mn, Na, P and Zn in seventeen iron supplement samples with different chemical composition. All results were evaluated by multivariate analysis tools, which have the ability to characterize the samples by chemical composition and the analyte content. Some samples showed higher values for some metals, indicating the importance of specific legislation also for these metals.

A procedure using slurry sampling for the determination of manganese in corn flour by ET AAS.

A fast and simple procedure is proposed for determination of manganese in corn flour samples employing slurry sampling and electrothermal atomic absorption spectrometry. To evaluate the particle size scanning electron microscopy was used. Slurries were prepared by weighing approximately 100 mg of sample, adding 0.014 mol L−1nitric acid, and a solution containing 1% Triton X-100. An ultrasonic bath was employed for slurry homogenization. Analytical variables including temperature program of the graphite furnace, nitric acid concentration, amount of sample and sonication times were studied. The pyrolysis and atomization temperatures established during the optimization step were 1200 and 2100 °C, respectively, using 10 μg Pd + 3 μg Mg as the chemical modifier. The limits of detection and quantification obtained were 0.006 and 0.020 μg g−1, respectively. A characteristic mass of 0.97 pg was obtained. The precision was evaluated for a sample containing 2.17 μg g−1 of manganese and 2.6% relative standard deviation was found (n = 10). The accuracy was assessed by the analysis of two certified reference materials: NIST SRM 1568a—Rice Flour and CRM 189—Wholemeal Flour. Some experiments demonstrated that the calibration can be performed employing the external calibration technique using aqueous standards. For comparison and validation of the procedure proposed, the samples were also analyzed after complete decomposition and determined by ETAAS and good precision was obtained (at 95% confidence level). In this way, no statistical difference was observed between the results obtained by both the procedures performed. The proposed procedure has been applied for manganese determination in six samples acquired in supermarkets of Salvador (Brazil) and values varied from 0.623 to 2.17 μg g−1.

Determination and Evaluation of the Metals and Metalloids in the Chapeu-de-couro (Echinodorus macrophyllus (Kunth) Micheli)

The Chapeu-de-couro (Echinodorus macrophyllus (Kunth) Micheli) is a native plant from Brazil, which has been mainly used in medicinal application being a potent antirheumatic and diuretic, in the production of soft drinks, and also in the ornamentation of aquariums. In this paper, the metals and metalloids for the leaves of chapeu-de-couro collected in the Paraguacu River from the city Cachoeira, Bahia State, Brazil, was determined and evaluated using multivariate analysis. The samples were digested using nitric acid and hydrogen peroxide and were analyzed using inductively coupled plasma mass spectrometry. The accuracy of the method was confirmed by analysis of a certified reference material of apple leaves, furnished by National Institute of Standard and Technology. The study involved 15 samples of the Paraguacu River. The results expressed as milligrams of element per kilogram of sample demonstrated that the concentration ranges varied: 1.39–5.27 for chromium, 44.85–165.39 for manganese, 0.55–0.84 for arsenic, 0.01–3.94 for antimony, and 0.18–0.31 for lead. The principal component analysis and hierarchical cluster analysis evidenced that the concentrations of the metals and metalloids varied according with the variations in the water of the Paraguacu.

Determination of the Mineral Composition of Watercress and Data Evaluation Using Multivariate Analysis

This paper reports the determination of the mineral composition of watercress (Nasturtium officinale Cruciferae, Brassicaceae), grown in soils from three cities in the Bahia State of Brazil, and in a fourth city where plants were grown in a hydroponic system. The sampling was carried out during the summer and winter. Analyses were performed with inductively coupled plasma optical emission spectrometry (ICP OES), and the accuracy was confirmed with a certified reference material of apple leaves. Principal component analysis (PCA) and hierarchical cluster analysis (HCA) revealed different mineral compositions of the samples collected in the summer and winter. Samples collected in the summer had a higher concentration of the nutrients iron, calcium, and magnesium, and the samples collected in the winter had a higher concentration of manganese and copper. The average contents of the samples (expressed as wet weight) were 2.50 and 3.03 mg g−1 for calcium, 0.37 and 0.86 mg g−1 for magnesium, 8.68 and 10.84 µg g−1 for iron, 8.42 and 8.47 µg g−1 for zinc, 0.61 and 0.47 µg g−1 for copper, and 7.78 and 5.03 µg g−1 for manganese for summer and winter, respectively. These results are in agreement with values previously reported in the literature. Samples collected from the hydroponic system in the winter had a lower concentration of all nutrients.

Mineral and centesimal composition evaluation of conventional and organic cultivars sweet potato ( Ipomoea batatas (L.) Lam) using chemometric tools

Sweet potato is a food consumed in the world. In this work, the minerals and centesimal composition in sweet potatoes of organic and conventional cultivars was investigated. The accuracy was confirmed with a certified reference material of apple leaves (NIST 1515). The quantification of the samples was performed by inductively coupled plasma optical emission spectrometry and the digestion efficiency was evaluated by residual carbon content. The mean concentrations (in mg/100 g) of minerals were: 23.5 and 40.7 (Ca); 0.082 and 0.159 (Cu); 0.303 and 0.481 (Fe); 197 and 381 (K); 166 and 35.7 (Mg); 0.183 and 1.15 (Mn); 68.6 and 0.433 (Na); 54.1 and 62.2 (P) and 0.197 and 0.261 (Zn) for conventional and organic cultivars, respectively. Average centesimal concentrations in conventional and organic cultivars (in %), were: 72 and 72 (moisture); 0.87 and 0.90 (ashes); 1.5 and 1.4 (proteins); 0.63 and 0.54 (lipids) and 24.8 and 23.9 (carbohydrates).

Microscopic and Chemical Characterization of Flour of Fruits: An Alternative Source for Supplemental Feeding

The present study aimed to characterization microscopic and chemical of four samples of fruit flours: eggplant (Solanum melongena), banana (Musa spp), passion fruit (Passiflora spp) and grape (Vitis vinifera). For the determination of chemical composition acid digestion was via a microwave-assisted using nitric acid and hydrogen peroxide and subsequently analysed by inductively coupled plasma Optical Emission Spectrometry (ICP OES). The validation of method was evaluated by analyzing a certified reference material (CRM), Rice Flour NIST 1568a. The vitamin C contents of the sample flour were determined by the AOAC procedure. The microscopic analyzes were realized with an optical microscope Olympus SZH10 coupled to a digital camera Cannon Power Shot A460. Average mineral concentration in flour samples (in mg/100 g) were: 0.30 to 367 (Ca); 3.38 to 1666 (K); 0.16 to 216 (Mg); 0.023 to 136 (Na); 0.010 to 9.95 (Cu); 0.050 to 27.87 (Fe); 0.052 to 6.55 (Mn); 0,011 to 6,04 (Zn) and 2,9 to 70,4 (Vitamin C). The principal component analysis (PCA) showed that the variables vitamin C and Na have negative correlation with Mn and these variables contribute to discrimination of samples of banana and passion fruit flour’s. Characteristic plant tissue components that compose the fruit flours were observed as well as the irregular addition of starch.

Speciation analysis based on digital image colorimetry: Iron (II/III) in white wine

This work proposes an analytical strategy utilizing digital images (DI) for the iron inorganic speciation in white wine. The method was established by the reaction of iron(II) ions with 1,2 ortho-phenanthroline as a chromogenic reagent. Total iron was determined using the same reagent after the addition of hydroxyl ammonium chloride as a reducing agent. In both cases, digital images of the standards/chromogenic reagent and samples were acquired and stored in JPEG format. The region of interest (ROI) was determined with a constant square shape for all images. The ROI was submitted to decomposition in color values according to the RGB additive color model. However, the data obtained by the blue channel was the one used in the construction of the analytical curves because it presented the highest sensitivity. The optimization of the experimental conditions of the procedure was performed by employing multivariate techniques. The precision was evaluated using a wine sample with iron (II) and total iron contents of 0.41 and 0.69 mg L-1, respectively. The results expressed as relative standard deviations were 3.57% for iron (II) and 4.76% for total iron contents. A comparison between the results obtained for total iron by the DI method with the results found using flame atomic absorption spectrometry confirmed the method accuracy. The DI procedure was applied for speciation analysis in six white wine samples and the contents found varied from 0.41 to 1.67 mg L-1 for iron (II) and from 0.69 to 1.71 mg L-1 for total iron. These results are in agreement with those found for speciation analysis of iron in wine samples. Iron (III) contents can be found by the difference between the total iron and iron (II) contents.

Screening of Mangifera indica L. functional content using PCA and neural networks (ANN)

A method using reversed-phase high-performance liquid chromatography with diode array detection (HPLC-DAD) was applied after extraction with acidified methanol, to determine 12 bioactive phenolic compounds in the peel and pulp of the mango fruit (Mangifera indica L.) cultivated in the Bahia, state of Brazil. The proposed methodology was previously fully validated and proven successful in the analysis of methanolic extracts of lyophilized samples. The limits of quantification ranged between 0.78 and 3.14 mg L-1 and the individual recovery values obtained for the spiked samples ranged from 80% to 120%. The results were evaluated using PCA and ANN. The results indicate that the fruits are rich in polyphenols, mainly: ellagic acid, gallic acid, rutin and catechin, which contribute to their greater use as functional foods, natural antioxidants and in the pharmaceutical industry, as well as other applications.