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This manuscript covers the application of the main techniques for simultaneous optimization of multiple responses generated by the application of multivariate designs (two-factor factorial, Central Composite, Doehlert, etc.) or by chromatographic runs in the development of analytical methods. Special attention will be given to the graphical method, desirability function, multiple response function and chromatographic response functions, since they are more frequently used in the analytical area. The advantages, disadvantages, limitations, and potentialities of these methods will also be addressed, as well as some of their applications, commenting on real examples from the literature. Some less usual methods in multiple response optimization in Analytical Chemistry will also be commented.

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.

Thallium (Tl) is a rare metal with toxic effects notably harmful to human health and the environment. In this article, the natural occurrence of Tl was evaluated in a deactivated manganese mine located in the Western region of Bahia, Brazil. The extraction procedure with aqua regia was used to dissolve the soil, sediment, and tailings samples. The Tl content was determined by differential pulse anodic stripping voltammetry (DPASV) and manganese (Mn) and iron (Fe) by flame atomic absorption spectroscopy (FAAS). The Tl levels ranged from 0.64 to 473 mg kg‑1, triggering an alert since most of the samples (soil and sediment) analyzed presented Tl concentrations above 1.0 mg kg-1, recognized as the maximum limit recommended by environmental agencies in North America and Europe.

In this study, mineral composition, centesimal composition and lead were evaluated in pine nut seeds (raw and cooked) from five Brazilian states. Mineral composition was determined by ICP OES and lead by GF AAS. The results for minerals were evaluated by Boxplot, PCA and HCA, using the R software. Average minerals in raw and cooked samples (mg 100 g−1) were: 15.2 and 10.8 (Ca), 0.168 and 0.113 (Cu), 0.506 and 0.330 (Fe), 536 and 420 (K), 51.3 and 40.6 (Mg), 0.373 and 0.208 (Mn), 132 and 102 (P) and 0.746 and 0.520 (Zn). The average centesimal composition (raw and cooked) was: 53.5 and 47.2% (moisture), 1.76 and 1.26% (ash), 3.90 and 3.53% (protein), 40.8 and 48.0% (carbohydrate) and 179 and 206 kcal/100 g (total caloric value) and Pb was not detected. The chemometric analysis showed a distinction of raw and cooked samples due to significant nutrient losses after thermal processing.

Made available in DSpace on 2021-06-25T11:49:04Z (GMT). No. of bitstreams: 0 Previous issue date: 2021-01-19 Fundacao de Amparo a Pesquisa do Estado da Bahia (FAPESB) Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq) Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) In this study, the concentrations of macro- and microelement in different tissues (liver, gill, and muscle) of fish collected (Mugil cephalus) in Pontal Bay (Ilheus, Bahia) were determined. A simplex-centroid mixture design was used to obtain the mixture applied to the decomposition of the samples. The elementary determination was made by microwave-induced plasma optical emission spectrometry (MIP OES), and the Kohonen self-organizing map (KSOM) was applied as an exploratory analysis tool. The accuracy of the procedure was assessed using certified reference material. Recoveries were obtained in the range of 99-103% and without a statistical difference (95% confidence level). Precision was estimated from the relative standard deviation, which ranged from 0.3 to 2.2%, and the limits of detection (mg kg(-1)) were 0.145 (Cu), 1.53 (Fe), 1.61 (K), 0.250 (Mg), 0.040 (Mn), 4.84 (P), and 2.12 (Zn). The KSOM provided efficient and precise separation of the studied tissues into three groups. The concentrations of Cu, Fe, and Zn were higher in the liver, while in the gills, they were the Mn. Univ Fed Bahia, Inst Chem, BR-40170290 Salvador, BA, Brazil Univ Fed Parana, Dept Chem, BR-81530900 Curitiba, Parana, Brazil Univ Estadual Paulista, Inst Chem, BR-14800060 Araraquara, SP, Brazil Univ Estadual Santa Cruz, Dept Exact & Technol Sci, BR-45662900 Ilheus, BA, Brazil Univ Estadual Paulista, Inst Chem, BR-14800060 Araraquara, SP, Brazil CNPq: 306698/2019-6 CNPq: 421694/2018-1 CAPES: 001

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).

Rose (Rosa spp.) petals have been used for the preparation of new cooking recipes, due to their sensory properties. In this paper were evaluated the micro (Co, Cu, Fe, Mn, Mo, Ni and Zn), macro (Ca, Mg, Na and P) and toxic elements (As, Cd and Cr) of organic cultivation rose by ICP OES and ICP-MS. The bioactive compounds (total phenolics, total flavonoids, total anthocyanins and antioxidant capacity in DPPH) were determined by UV-VIS spectrophotometry. Chemometric tools were used in method optimization, such as full factorial design for acid digestion and Box-Behnken design for total phenolics, in addition to the application of Artificial Neural Networks with Kohonen Neural Network for bioactive compounds. The application of PCA and HCA showed that the mineral composition of rose petal samples had differences between summer and winter. The accuracy of the method was confirmed by the analysis of three certified reference materials: apple leaves (1515), spinach leaves (1570a) and peach leaves (1547), from the National Institute of Standards and Technology (NIST). Digestion efficiency was evaluated by residual carbon content. The developed methods were promising to evaluate the minerals, toxic elements and bioactive compounds in rose petals, and the results indicate that they can be added as a potential nutritional supplement in the human diet.

This study proposes a preliminary assessment of the homogeneity and stability through digital image acquisition of a candidate for mechanically processed pumpkin seed meal reference material, exploring the concepts of homogeneity curve and the analysis of texture characteristics by Continuous-Level Moving Block through Robust Principal Component Analysis. This innovative methodology allowed us to examine the percentage of homogeneity in a set of samples, revealing an average of 41% with only one outlier in relation to the entire sample, indicating low homogeneity. In the stability study carried out after storing samples for 12 months at different temperatures, 83% of the samples were considered regular and 17% were outlier, which means that most of them were considered stable. Therefore, this methodology is useful for screening samples for homogeneity, by textural analysis, and detected non-homogeneity can be corrected in advance for quantification by standard protocols.

The development of a collaborative study as a requirement for the preparation of a laboratory reference material candidate is reported in this paper. The evaluation was performed by 13 laboratories invited to quantify the calcium, potassium, magnesium, phosphorus, copper, iron, manganese and zinc; 8 of them presented results for all the analytes under investigation. The data were statistically analyzed by applying the z-score robust technique as recommended by ISO Guide 35. For the potassium element, laboratories 4 and 13 presented questionable results. Laboratory 5 proved to be unsatisfactory for calcium and zinc. ANOVA-PCA and DD-SIMCA were also applied to evaluate stability and interlaboratory studies results, respectively. It has been demonstrated that multivariate data analysis can be successfully applied as an alternative method to the recommendations made by ISO 13528 and ISO Guide 35 with defined confidence intervals.

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 30 min. The chromatographic separation was performed using a mobile phase containing 1.0 mM tetrabutylammonium hydroxide (TBAH), 0.7 mM 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 5 min, 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 0.14 µg g−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 1.3 µg g−1 for arsenic, and from 0.4 to 61.2 µg g−1 for chromium.

A reliable, simple and accurate method was developed to simultaneously determine 13 bioactive phenolic compounds in guava ( Psidium guajava L.) by reversed-phase high-performance liquid chromatography with diode array detection (HPLC-DAD). The proposed methodology was fully validated and proven successful in the analysis of methanolic extracts of lyophilized whole guavas at two maturation stages: green and ripe. The quantification of phenolic compounds revealed that the highest concentrations (mg 100 g − 1 DW) in all samples were: gallic acid (2.43–7.28); chlorogenic acid (1.83–10.75); ellagic acid (5.72–30.60); catequin (1.09–13.09) and rutin (5.09–45.02). Total polyphenol content (55–516 mg GAE 100 g − 1 ); total flavonoid content (35.26–75.19 mg QE 100 g − 1 ); antioxidant capacity in DPPH and ABTS assays (5.22–5.62 and 17.63–18.74 TEAC·100 g − 1 DW, respectively) were also determined, and can be related to the diverse range of phenolics detected. The results (TPC and TFC) for most green samples were higher than for ripe samples. There were no significant differences for antioxidant activity between the samples analyzed. Applying Pearson correlation test, the results indicate a significant positive correlation between the variables. The exploratory evaluation of guava samples was performed through Principal Component Analysis (PCA). The bioactive phenolics that most contributed to the variability between green and ripe fruits were: rutin, catequin, and: elagic, syringic, cafeic, transcinamic and p-coumaric acids. Neural Network Analysis (NNA) was applied for more insights about cluster separation and the influence of each variable. The parameters evaluated for NNA indicated good separation in two clusters: green and ripe fruits.

This study is the first to propose the simultaneous quantification of 10 elements in fruits of Casearia fasciculata by inductively coupled plasma optical emission spectrometry (ICP OES). A method of digestion using dilute nitric acid was optimized by mixture design for extraction of elements in the seed, peel, and pulp of Casearia fasciculata cultivated in the Bahia State, Northeastern Brazil. Four different approaches were used to evaluate the digestion procedure ((i) desirability; (ii) multiple response; (iii) residual carbon content and (iv) residual acidity). The accuracy of the method of digestion was applied for the extraction of the studied elements in two certified reference materials (RM-Agro E1001a Brachiaria brizantha and NIST 1515 apple leaves). The limits of quantification of the method (µg g−1) were: Cr, 0.42; Cu, 0.69; Fe, 1.5; Mn, 0.14; Zn, 1.8; Ca, 29.0; K, 3.5; Mg, 1.9; P, 6.4; and S, 17. Two multivariate tools, principal component analysis (PCA) and hierarchical cluster analysis (HCA), were efficient in the formation of groups, corresponding to the fruit parts. Thus, the peel and seed of Casearia fasciculata present potential to be used as mineral supplements in human nutrition.

Emulsified systems are characterized by an immiscible liquid dispersed in another liquid in the form of droplets. These systems can be classified according to the size of the dispersed droplets obtained in coarse emulsions (0.5–50 µm) or microemulsions (0.01–0.10 µm). These systems have several properties that make them interesting in several fields of technology, and the emulsion formed by oil droplets dispersed in an aqueous phase (O/A) is the most used in analytical determinations due to its low viscosity and organic load. This paper discusses the characteristics of emulsified systems, their obtention, stabilization, properties and use in the development of analytical methods for elemental analysis in matrices with high organic content such as oils, fatty foods and fuel matrices.

To assess environmental contamination, studies have been increasingly carried out using biomarkers to diagnose the effects of toxic metal exposure, such as metallothionein (MT). In this context, the aims of the present study were to determine Cd, Cu, Ni and Pb concentrations, by ICP-MS, in liver samples from Mugil cephalus from the municipality of Ilheus, located in North-Southeastern Brazil, in the state of Bahia, which has been increasingly suffering from anthropogenic pressure, and to quantify total MT in liver and gills. Among essential metals, copper (199.2 μg g−1) presented concentrations approximately 7 times higher than allowed by the World Health Organization (30 μg g−1). Liver samples showed higher concentrations than gills. Metallothionein concentrations indicate differential contamination along the study area. The first sampling showed higher induction of MT synthesis overall. Differences between liver and gill MT concentration trends were relatively minor, which may indicate the adequacy of analyzing gills in an environmental monitoring context.

Corn is one of the most consumed cereals in world and the second most cultivated in Brazil. Cereal flour has a flavor well accepted by the Brazilian population. This work describes the preparation and characterization of a new corn flour reference material which can be used as a quality assurance tool to demonstrate the reliability of the analytical results obtained from inorganic analysis of cereals and their derivatives. The studied elements were Ca, K, Mg, P, Cu, Fe, Mn and Zn. Homogeneity and stability tests, material characterization and attribution of uncertainty value were performed in this work by following recommendations of ISO Guides 30–35. The material was shown to be homogeneous and stable for 15 months at temperatures of −10 °C, +25 °C and +45 °C, with small uncertainty. Alternatively, the data were analyzed by hierarchical clustering technique and the stability was confirmed. The confidence ellipse technique enabled a simple and fast evaluation of data supplied by collaborating laboratories allowing the exclusion of outlying values and indicating possible causes of the deviations.

Submitted by Gisele Mara Hadlich (gisele@ufba.br) on 2019-01-14T01:47:21Z No. of bitstreams: 1 Determination and evaluation of the mineral composition of breadfruit (Artocarpus altilis) using multivariate analysis technique.pdf: 533500 bytes, checksum: 2126fa71b9fb9c9133a217f866568538 (MD5) Approved for entry into archive by Jessica Alves (alves.jessica@ufba.br) on 2019-03-20T13:47:47Z (GMT) No. of bitstreams: 1 Determination and evaluation of the mineral composition of breadfruit (Artocarpus altilis) using multivariate analysis technique.pdf: 533500 bytes, checksum: 2126fa71b9fb9c9133a217f866568538 (MD5) Made available in DSpace on 2019-03-20T13:47:47Z (GMT). No. of bitstreams: 1 Determination and evaluation of the mineral composition of breadfruit (Artocarpus altilis) using multivariate analysis technique.pdf: 533500 bytes, checksum: 2126fa71b9fb9c9133a217f866568538 (MD5) Breadfruit is a fruit originated from South Pacific and afterward it was widespread in rest of Oceania. In Brazil it is known as “fruta pão” and has been consumed mainly by humble people. In home use, breadfruit has been consumed cooked, fried or roasted. Industrially, it has been employed to prepare breads and flours. In the present paper, the mineral composition of breadfruit (Artocarpus altilis) was determined and evaluated. Raw breadfruit samples and cooked using domestic methods as boiling and microwave heating were digested in acid media and the elements potassium, calcium, phosphor, magnesium, iron, sodium and manganese were determined employing inductively coupled plasma optical emission spectrometry (ICP OES). Cadmium and lead were also determined using graphite furnace atomic absorption spectrometry (GFAAS), but the concentrations found were lower than the limits of quantification for these elements. Eleven samples were acquired in several cities from Bahia state, Brazil. All these samples were analyzed in triplicate. The data obtained were evaluated employing the multivariate analysis techniques: Principal Component Analysis (PCA) and Hierarchical Cluster Analysis (HCA). Both techniques showed that the cooking methods using microwave heating and boiling cause loss of the nutrients. PCA also evidenced that the element concentrations in the samples cooked using microwave heating are higher than in the samples cooked by boiling using stove. The average concentrations of the determined elements (expressed as mg 100 g−1 of sample) in raw samples were as follows: 269.4 for potassium, 40.97 for phosphorus, 26.32 for calcium, 24.35 for magnesium, 1.41 for sodium, 0.1891 for iron and 0.0381 for manganese. Microchemical Journal

This review covers the application of multivariate designs and mathematical-statistical techniques to establish optimal conditions of the analytical methods for elemental analysis using inductively coupled plasma optical emission spectrometry (ICP OES) as a detection technique. The main experimental designs, such as two level factorial design, central-composite design, Box Behnken design, Doehlert design and mixtures designs are presented and discussed in connection to the method stage, in which multivariate designs were used in the instrumental variable optimization related to plasma, sample decomposition, preconcentration stage and sample introduction technique.

In this work, a simple, fast, and robust method was developed for the direct and simultaneous determination of copper and iron in flours using solid sample analysis and high-resolution continuum source graphite furnace atomic absorption spectrometry. The secondary lines at 217.894 and 217.812 nm were used for all simultaneous measurements of copper and iron, respectively. The pyrolysis and atomization temperatures were of 1400 and 2400 °C, respectively, and no chemical modifier was necessary. The slope of calibration curve obtained, using the rice flour certified reference material (NIST 1568a) as solid standard, presented no significant difference when compared with the slope of external calibration curve using aqueous standard, at 95 % confidence level. Under these conditions, the limits of quantification obtained were 0.38 (Cu) and 0.11 (Fe) mg kg−1, respectively. The relative standard deviations (RSD) varied from 0.5 to 14 % for copper and from 4.9 to 17 % for iron. The method accuracy was confirmed by analysis of two certified reference materials, rice flour NIST 1568a and wheat flour NIST 1567a, and the results were in agreement with the certified values, at 95 % confidence level. The proposed method was applied for the analysis of flour samples (corn, wheat, and white bean), both of conventional and organic cultivation. The concentration values varied in the range of 0.6–5.9 mg kg−1 for copper and of 2.6–50.4 mg kg−1 for iron. The iron concentrations in all samples analyzed were not in agreement with the value established by the Brazilian legislation, which is of 42 mg of iron per kilogram of flour.

The present work reports the development of an analytical method for the determination of trace amounts of Cd and Pb in crude palm oil using graphite furnace atomic absorption spectrometry (GF AAS) after extraction induced by emulsion breaking (EIEB). The method was based on an oil-in-water emulsion preparation to promote a high contact area between the sample drops and the acid extractant solution. Emulsification was assisted by ultrasound energy using HNO3 and Triton X-114 surfactant solutions to increase the efficiency of the extraction. Afterwards, the emulsion was broken by heating, and the acid aqueous phase in the bottom of conical glass tubes was collected for the determination of metals by GF AAS. Cadmium and lead extraction was simultaneously optimized using Doehlert design and desirability function. The best extractions were achieved using a sonication time of 18 min, a HNO3 concentration of 2.0 mol L−1 and a surfactant concentration of 4.4% (v v-1) at a breaking temperature of 90 °C. The developed method presented quantification limits of 0.17 and 0.13 μg kg−1 and precisions (repeatability,%RSD, 10.8 μg kg−1) of 1.8 and 5.4% for Cd and Pb, respectively. Addition/recovery tests gave results between 88.5% and 112%. The amounts of Cd and Pb in the analyzed samples ranged from 1.5–2.5 and 2.53–6.76 μg kg−1, respectively.

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 400 mg 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.

In this study, it was developed a method for Ca, Mg, Mn, Fe and Zn determination in palm oil samples by flame atomic absorption spectrometry (FAAS) after ultrasound-assisted emulsification and extraction induced by emulsion breaking (EIEB). Optimization of the method was carried out by a constrained mixture design. The developed method has presented limits of detection (LOD) between 0.012 and 0.057 mg L-1, limits of quantification (LOQ) between 0.039 and 0.19 mg L-1 and precision was expressed as repeatability (%RSD, n = 10) between 1.8 and 3.2% for the five studied metals. Method accuracy was assessed by the application of recovery tests (87 to 113%) and by comparison of concentration values with the dry ashing method, showing good agreement with the standard method. The developed methodology allows operational simplicity, multi-sample treatment, and low cost when compared with some methods based on decomposition. It was applied in palm oil samples collected in the Bahia State (Brazil). The concentrations (in mg L-1) found in the samples were: 3.93-13.9 Ca, 0.37-2.26 Mg, > LOQ-0.32 Mn, 1.77-8.57 Fe and 0.38-2.54 Zn.

The use of a palladium film electrode (PdFE) as an alternative electrode for the determination of thallium (Tl+) and lead (Pb2+) in water samples by anodic stripping voltammetry is proposed. Preliminary studies of the influence of the substrate were performed on the electrochemical behavior of PdFE prepared ex situ. Using a silver solid amalgam electrode as substrate (AgSAE), the effect of several parameters such as potential and deposition time, composition and pH of supporting electrolyte on the analytical response of PdFE for Tl+ by differential pulse anodic stripping voltammetry (DPASV) was initially investigated. Under best experimental conditions of deposition potential of −1.2 V and deposition time of 300s the analytical curve was linear in the Tl+ concentration from 3.0 to 100.0 µg L−1 with a relative standard deviation (RSD)

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.

Cassava leaves (Manihot esculenta) are used to prepare “manicoba”. Of indigenous origin, this dish is considered of high nutritional value for Brazilian cuisine. However, the leaves should be processed in order to eliminate the hydrocyanic acid that they contain. In this work, the centesimal composition, physical-chemical characteristics, micro (Cu, Mn, and Zn) and macronutrients (Ca, K, and Mg) were evaluated in cassava leaves cultivates in the State of Bahia, Brazil, according to different types of processing the leaves. The centesimal composition and physical-chemical characteristics were determined employing methodologies described by Adolfo Lutz Institute. The determination of the mineral composition was performed employing ICP OES, after microwave-assisted acid decomposition procedure of leaves samples. The accuracy of the method was confirmed by the analysis of spinach and apple leaves certified reference materials (NIST 1570a and NIST 1515) from the National Institute of Standards and Technology (NIST). Residual carbon content was evaluated by ICP OES. The samples were evaluated raw and after the cooking and fermentation processes. Losses of nutrients occurred after the cooking and fermentation processes. Average mineral concentrations in raw, cooked and fermented samples (in mg 100 g−1) were: 502.0, 487.6 and 458.4 for Ca; 40.1, 37.6 and 29.1 for Cu; 781.2, 180.9 and 57.8 for K; 150.3, 133.2 and 111.4 for Mg; 20.3, 18.8 and 15.7 for Mn; and 5.01, 4.64 and 4.02 for Zn. Average centesimal composition concentrations in raw, cooked and fermented samples (in % m m−1) were: 29.9, 12.2 and 11.1 for moisture content; 2.03, 0.66 and 0.54 for ashes; 10.2, 4.66 and 4.64 for proteins; 1.64, 1.88 and 1.07 for lipids; 56.3, 80.6 and 82.6 for carbohydrates; and 281, 358 and 359 for calorific value. Average physical-chemical characteristics values in raw sample were: 0.16–1.17% (titratable acidity); 5.91–6.41 (pH); 2.75–3.27 °Brix (soluble solids); 2.75–3.27 (ratio) and 4.53–38.7 mg 100 g−1 (vitamin C). The results were evaluated using multivariate analysis (PCA and HCA), in which there is a tendency of separation of the samples in groups, according to the treatment type that the samples were submitted.

Okra ( Abelmoschus esculentus L .) is a plant native to Africa. It was introduced to Brazil with the slave trade and spread to all regions, including the state of Bahia, northeastern Brazil. In this work, the mineral content of raw and cooked okra marketed in the state of Bahia, of both conventional and organic cultivars was determined. The results were evaluated using multivariate analysis. The samples were digested in a heating block using nitric acid and hydrogen peroxide, and analysed using inductively coupled plasma optical emission spectrometry (ICP OES). The accuracy of the method was confirmed using a standard reference material, tomato leaves (NIST 1573a). Average mineral concentrations in raw and cooked okra (in mg/100 g), were: 366 to 325 (Ca); 0.102 to 0.052 (Cu); 267 to 97.7 (K); 45.3 to 18.3 (Mg); 18.3 to 7.00 (Na); 44.5 to 25.8 (P); and 0.233 to 0.094 (Zn). Raw and cooked samples tended to separate in principal component analysis (PCA) and hierarchical cluster analysis (HCA). The elements that contributed most for the variability between raw and cooked samples are: K, P, Mg, Cu, Na and Zn, with minor contributions from Ca.

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.

Broccoli (Brassica oleracea L. var. Italica) is a vegetable food that belongs to the family Cruciferaceae, and it is a good source of vitamins and minerals. Among other characteristics, the kind of culture (conventional or organic), the climate of origin, and the way a vegetal will be consumed influence directly in the concentrations of minerals. The aim of this work was to determine mineral composition (Fe, Mn, Zn, K, Ca, Mg, and Na) of 16 broccoli samples collected in four cities of Bahia, Brazil, in summer and winter, from organic and conventional cultures. These elements were also determined in a lot of raw and cooked summer samples and then all results were evaluated using multivariate analysis. Broccoli samples were analyzed by inductively coupled plasma optical emission spectrometry after digestion with HNO3 and H2O2. The results expressed as milligrams of element per 100 g of sample demonstrated that the concentration ranges for conventional and organic broccoli varied, respectively, from 0.13 to 0.90 and 0.14–1.18, for iron; from 0.15 to 1.79 and 0.04–1.40, for manganese; from 0.20 to 1.58 and 0.17–1.28, for zinc; from 317.65 to 484.45 and 321.58–521.78 for potassium; from 7.14 to 153.50 and 9.38–131.55, for calcium; from 21.09 to 47.15 and 29.51–61.23, for magnesium; from 3.66 to 21.21 and 1.89–27.09 for sodium. The accuracy of the method was confirmed by analysis of a certified reference material of spinach leaves (NIST 1570a). The statistical evaluation of the obtained results showed that broccoli samples were not differentiated by city of origin, station, or culture. Nevertheless, by comparing raw and cooked samples, it was noticed a tendency of separation in the principal component analysis and hierarchical cluster 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...

Inductively coupled plasma optical emission spectrometry was used to determine the elements present in Chinese cabbage (Beta vulgaris). The accuracy of the method was confirmed by analysis of a certified reference material of spinach leaves. The study involved 57 samples that were collected in 13 Brazilian cities. Average concentrations of elements found per gram of Chinese cabbage were as follows: 3.44 mg g−1 sodium, 5.09 mg g−1 potassium, 1.25 mg g−1 phosphorous, 0.85 mg g−1 calcium, 0.49 mg g−1 magnesium, 2.79 μg g−1 manganese, 9.50 μg g−1 iron, 0.74 μg g−1 copper, 14.28 μg g−1 zinc, and 6.44 μg g−1 strontium. Principal component analysis and hierarchical cluster analysis demonstrated that there is no systematic difference in the mineral composition between the cabbage samples that were analyzed.

This paper describes the determination and evaluation of the mineral composition (calcium, magnesium, iron, manganese and zinc) of kale (Brassica oleracea L. var. acephala DC.) grown in soils within four cities in Bahia State, Brazil. The sampling process was performed during the summer and winter. Samples were digested with concentrated nitric acid and a digestion pump. 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 furnished by the National Institute of Standard and Technology. 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 winter have a higher concentration of micronutrients (iron, zinc and manganese) and macronutrients (calcium and magnesium). The average contents (wet weight and mg per 100 g) for the winter and summer were 551 and 535 for calcium; 117 and 106 for magnesium; 2.13 and 1.48 for iron; 2.63 and 1.95 for zinc and 2.05 and 1.34 for manganese, respectively. These results are in agreement with values previously reported in the literature.

The development of a homogeneity study during the preparation of a wheat flour laboratory reference material (LRM) for use in the quantification of metals and metalloids is reported. Inductively coupled plasma optical emission spectrometry (ICP OES) was used with validation performed using a certified reference material of wheat flour furnished by the National Institute of Standards and Technology (NIST). Copper, iron, manganese, phosphor, strontium and zinc were studied in a within-bottle homogeneity test whereas barium, copper, iron, zinc, manganese, strontium, phosphor and calcium were included in a between batch homogeneity study. Standard univariate analysis of variance (ANOVA) was performed for all analytes. Furthermore an alternative multivariate analysis for homogeneity is proposed by performing ANOVA of principal component scores and by inspection of principal component score graphs and hierarchical cluster analysis dendrograms. The ANOVA F -tests performed on both, the univariate and multivariate parameters, were not significant at the 95% confidence level and indicated homogeneous wheat flour samples. A 10 kg amount of material was processed, which was distributed in 100 bottles, each containing 100 g. For the between-bottle homogeneity test, three replicates were taken from each of 10 bottles selected of the 100 bottles obtained. The results were evaluated using an F-test , which demonstrated no significant difference for the between-bottle results. It is indicative that this material is homogeneous. Afterwards, the influence of the sample mass on the homogeneity of the material was also evaluated by quantification of the elements for 100, 300, 500, 700 and 1000 mg sample masses with all the experiments being performed in triplicate. The F -test was also used for evaluation of these results and demonstrated that the material is homogeneous for masses taken in the 100 to 1000 mg range. All these results were further evaluated employing the principal component analysis (PCA) and hierarchical cluster analysis (HCA) multivariate techniques. Both techniques also demonstrated that the material is perfectly homogeneous for use as laboratory reference material.

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.

The homogeneity and stability of metals were tested in a candidate laboratory reference material of soy leaves. Inductively coupled plasma-optical emission spectrometry was used to quantify calcium, magnesium, manganese, iron, zinc, copper, and vanadium. A 6 kg amount of the material, which was dried, ground, and classified as mesh 60, was distributed among 100 bottles. The between-bottle homogeneity test was established by analyzing two subsamples from nine bottles. For the within-bottle test, five determinations of each element of a single bottle were performed. The stability test was performed at temperatures of –10, +27, and +40°C, and after storage times of 4, 12, 24, and 52 weeks. The obtained results indicated that the material was homogeneous and stable under the conditions studied.

Texto completo: acesso restrito. p. 376–382 Submitted by Edileide Reis (leyde-landy@hotmail.com) on 2014-04-03T15:05:51Z No. of bitstreams: 1 Icaro T.A. Moreira.pdf: 1762267 bytes, checksum: c5e190530fbcdbd9f9b5a82772ec46e7 (MD5) Approved for entry into archive by Rodrigo Meirelles (rodrigomei@ufba.br) on 2015-10-09T18:44:15Z (GMT) No. of bitstreams: 1 Icaro T.A. Moreira.pdf: 1762267 bytes, checksum: c5e190530fbcdbd9f9b5a82772ec46e7 (MD5) Made available in DSpace on 2015-10-09T18:44:15Z (GMT). No. of bitstreams: 1 Icaro T.A. Moreira.pdf: 1762267 bytes, checksum: c5e190530fbcdbd9f9b5a82772ec46e7 (MD5) Previous issue date: 2011 In this study developed a pilot-scale experiment during 0–3 months on the implementation of a Phytoremediation model with species Rizophora mangle L. and a model of Intrinsic Bioremediation, in order to try to compare which model would achieve the maximum effectiveness of degradation of total petroleum hydrocarbons in mangrove sediment. After 90 days a higher efficiency in removing organic compounds from sediment by Phytoremediation (87%) was observed. This larger efficiency in the remediation of the plant was enhanced with the largest growth of bacteria in its rhizosphere, reaching the highest CFU g− 1, 31 × 106. It was observed a larger growth of plants exposed to contaminated sediments (46.3 cm) compared to those grown in reference sediments (34.4 cm), suggesting a good adaptation. The data showed that the Phytoremediation is an effective in the degradation of TPH's, becoming a promising option in the application of the technique in mangrove areas.

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.