Digestion Block Research Articles

NPK Biofertilizer Production from Banana Peel, Feather and Bone Ashes and their Comparative Advantage to 20:10:10 Inorganic Fertilizer

The possibility of formulating nitrogen, phosphorus and potassium (NPK) biofertilizer from ashes of waste organic materials such as chicken feathers, bone and banana peels is investigated in this study by first subjecting the agricultural waste to 80-250 heat in a muffle furnace to produce ash. Kjeldatherm block digestion unit, UV spectrophotometer, and flame photometers, respectively helped in measuring the concentrations of N, P and K inherent in the fertilizer precursors as well as in 5 formulated blends (i.e., A, B, C, D & E). It was discovered that NPK in the single substrate and blends favorably compared with standard NPK 20:10:10 chemical fertilizer to some extent. Among single material fertilizer sources, feather ash with 0.179:1:0.134 NPK and bone ash with 0.009:1:0.021 NPK had the closest nutrient content with the standard, showing potential promise. On the other hand, Blend E is the same as the standard, followed by Blend A, B, D and C, which are hierarchically close in elemental composition to the standard. The choice of these biofertilizers is dependent on their nutrient compositions, the type of crops to be grown, and the soil mineral requirements. Most importantly, different NPK ratio organic fertilizers produced in this study can competitively be produced in a large scale to address huge costs associated with the NPK 20:10:10 standard commercial fertilizer. Blend E (NPK 20:10:10) can be formulated locally by farmers in rural areas easily using this particular agricultural residue or a host of other confirmed farm wastes.

Selenium in plant-based beverages: How can in vitro bioaccessibility contribute to an accurate daily intake?

BackgroundLactose intolerance, cow milk protein allergy, and environmental and ethical concerns drive the global market for plant-based beverages (PPBs). Despite this, data on the occurrence of selenium (Se) in these beverages are scarce. ObjectiveThe objectives of this study were to assess total selenium and determine the bioaccessible fractions in plant-based beverages (PBBs) from cereals, oilseeds, and pumpkin seeds, using an in vitro static method to simulate human digestion; and estimate the contribution these beverages have to the reference daily intake (RDI) for children and adults. MethodologyThe study involved beverages made under laboratory conditions. Samples and extracts were submitted to acid digestion (ultrasonic and block digester); total and bioaccessible Se levels were determined by ICP-MS. In vitro bioaccessibility was assessed using the INFOGEST protocol. ResultsThe results revealed a wide variation in Se content in the studied plant-based beverages from 10.3 µg kg−1 (sunflower seeds) to 3509 µg kg−1 (Brazil nuts). The bioaccessibility of Se was found only in PBBs made from oilseeds with macadamia, cashew and Brazil nut, with a variation in values from 86 to 96 %. The Se content and its bioaccessible fraction of Brazil nut PBB may contribute to 1276 % and 1218 % of the RDI for children and adults, respectively. ConclusionsThe Se content varied among samples of cereals, oilseeds and pumpkin seeds, reflecting the diversity in the studied PBBs. Only PBBs containing oilseeds (macadamia, cashews, and Brazil nuts) exhibited measurable amounts of bioaccessible Se, indicating an association with the raw material. However, the consumption of the PBB containing Brazil nuts may pose a risk of adverse effects, due to its high contribution to the RDI in both children and adults.

Electronic waste analysis using laser-induced breakdown spectroscopy (LIBS) and X-ray fluorescence (XRF): Critical evaluation of data fusion for the determination of Al, Cu and Fe

BackgroundElectronic waste (e-waste) proliferation and its implications underscore the imperative for advanced analytical methods to mitigate its environmental impact. It is estimated that e-waste production stands at a staggering 20–50 million tons yearly, of which merely 20–25% undergo formal recycling. The e-waste samples evaluated contain computers, laptops, smartphones, and tablets. ResultsForty-one samples were processed, involving the disassembly and separation of components. Subsequently, two analytical techniques, laser-induced breakdown spectroscopy (LIBS) and energy dispersive X-ray fluorescence (ED-XRF), were applied to quantify aluminum (Al), copper (Cu), and iron (Fe) in the e-waste samples. The samples were then analyzed after acid mineralization with 50% v v−1 aqua regia in a digester block and finally by ICP OES. A solid residue composed of Si and Ti was observed after the digestion of the samples. Multivariate calibration strategies such as partial least-squares regression (PLS), principal component regression (PCR), maximum likelihood principal component regression (MLPCR), and error covariance penalized regression (ECPR) were used for calibration. Finally, the figures of merit were calculated to verify the most suitable models. The results revealed robust models with notable sensitivity, varying from 8.98 to 35.04 Signal (a.u.)(% w w−1) −1, low Limits of Detection (LoD) within the range of 0.001–0.2 % w w−1, and remarkable relative errors ranging from 2% to 33%, particularly for Cu and Fe. SignificanceNotably, the models for Al faced inherent challenges, thus highlighting the complexities associated with its quantification in e-waste samples. In conclusion, this research represents an important step toward a more sustainable and efficient future for electronic waste recycling, signifying its relevance to global environmental welfare and resource conservation.

Geochemical base for As, Co, Cu, Ni, P, Pb, S, V and Zn in road dust collected in areas of oil industry activity in the Metropolitan Region of Salvador, Bahia, Brazil

Road dust collection was carried out in Salvador and some municipalities in the Metropolitan Region of Salvador (MRS), such as Simões Filho, Candeias, Madre de Deus and São Francisco do Conde, situated within an area of oil activity. In the chemical-physical characterisation of the road dust collected, the average fractions of coarse sand (17.44 %), medium (27.15 %), fine (32.63 %) and very fine (15.54 %) were found in the 17 samples collected. The samples underwent an acid extraction procedure in a closed digester block, with the mixture HCl + HNO3 + H2O2. The extract was analysed and concentrations of Al, As, Co, Cu, Fe, Ni, Pb, P, Sb, V and Zn were determined. Linear regression analysis was applied to the concentrations of As, Co, Cu, Ni, Pb, P, V and Zn, generating the equations of the straight lines, which served as a geochemical baseline for the region of road dust samples. For the enrichment factor (EF), most chemical elements showed values lower than < 1 at the collection points, except for Cu, Mn, and P (10 < EF < 25) and for Co, Cu, P and Ni (5 < EF < 10), in the regions of Candeias and Simões Filho. On the other hand, the geoaccumulation index (Igeo) of most points were evaluated as uncontaminated (class 0) and moderate or uncontaminated (class 1) for Igeo, except for P (class 4) and Mn (class 5). Principal component analysis (PCA) showed accumulated total variance corresponding to 76.45 %. For the hierarchical cluster analysis (HCA), the results agree with those found in the PCA. Points P3 (Candeias) and P16 (Simões Filho) were the points that showed less dissimilarity with the other points analysed, indicating possible enrichment of the chemical elements found at these points, confirmed by the EF values.

Determination of Ca, P, K, Na, and Mg in Australian Retail Pasteurised Milk Using Inductively Coupled Plasma Atomic Emission Spectroscopy (ICP OES)

A rapid and simple inductively coupled plasma atomic emission spectrometry (ICP OES) method was developed and validated for the determination of macroelements including calcium (Ca), phosphorus (P), potassium (K), sodium (Na), and magnesium (Mg) in Australian retail pasteurised milk. The milk samples were digested using the mixture of 70% HNO3 and 30% H2O2 (2 : 1, v/v) in an open‐tube digester block at 120°C for 4 h. The validated ICP OES method showed good linearity for all elements (R2 &gt; 0.9993). The method limits of quantification (LOQ) for Ca, P, K, Na, and Mg were 19.85, 8.97, 100.8, 41.92, and 11.56 µg·g−1, respectively. Recoveries were in the range of 91.54–116.0%. Repeatability and interday reproducibility expressed as the relative standard deviation (% RSD) was below 5.0%. The contents of macroelements in 6 retail pasteurised milk samples were between 1099.32 and 1348.65 µg·g−1 (Ca), 914.01 and 1091.21 µg·g−1 (P), 1362.76 and 1549.74 µg·g−1 (K), 288.89 and 323.22 µg·g−1 (Na), and 97.62 and 110.57 µg·g−1 (Mg). Principal component analysis (PCA) revealed that retail pasteurised milk samples were distinctly separated into four groups on the first two principal components (PCs). The difference in the macroelement content between milk brands might be affected by milk regions.

Evaluation of Total Concentrations and Bioaccessible Fractions of Essential and Toxic Elements in Amaranth, Quinoa and Chia by MIP OES

The total concentrations and the bioaccessible fractions of Al, B, Ba, Ca, Cu, Fe, K, Mg, Mn, Na, Ni, V and Zn were evaluated in 10 samples of pseudocereals, being 3 of amaranth, 3 of quinoa and 4 of chia. The samples were decomposed in a digester block with a reflux system under conditions optimized and the analyses were performed by microwave-induced plasma optical emission spectrometry. In all grains investigated, the highest total concentrations were found for the macroelements K, Mg and Ca, as well as the microelements Fe, Mn, and Zn. When the bioaccessible fraction was evaluated, negative correlations were observed between the content of total phenolic compounds and the bioaccessibility for most elements, in all samples. Among the elements considered essential in our diet, K (99%) and Cu (59%) presented the highest percentages of bioaccessible fraction. Among those elements considered potentially toxic, Ba did not exceed 15% bioaccessible fraction and Al presented concentrations lower than the limit of detection in all samples.

Green sample preparation of medicinal herbs in closed digester block for elemental determination by ICP OES

This work presents a simple, cost-effective, and environmentally friendly digestion method employing inductively coupled plasma optical emission spectrometry (ICP OES) for the determination of As, Ca, Cd, Cr, Cu, Fe, K, Mg, Mn, Na, P, Pb, Sr, and Zn in medicinal herbs. A fractional factorial design uses a multivariate strategy to optimize the experimental parameters. At 180 ºC and 120 min of sample digestion, the optimal condition for a closed block digester was achieved with a mixture consisting of 1.38 mL of HNO3 65% m m−1, 1.00 mL of H2O2 30% m m−1, and 2.62 mL of deionized water, using a mass of 0.10 g medicinal herb sample. The optimized procedure resulted in low dissolved organic carbon content and residual acidity concentration. The values of limits of detection (LOD) and of quantification (LOQ) ranging from 0.06 (Cd) to 1.9 (P) mg kg−1 and 0.2 (Cd) to 6.3 mg kg−1 (P), respectively. Accuracy was confirmed through the analysis of three certified reference materials, where agreement ranged from 83 (Sr) to 116% (As) for all analytes. The AGREE metric has confirmed the greenness of the proposed method. Twenty-seven medicinal herbs samples were used to assess the applicability of the developed procedure. Principal component analysis (PCA) was applied to inorganic constituent concentration data to classify the medicinal herbs, an excellent tool for classifying samples.

Concentrations of macro and microelement in Brazilian white cheeses: Evaluating sample preparation procedures and estimation of dietary intake

Two sample preparation procedures, microwave-assisted and closed digestion block, were developed to establish the nutritional content of white cheeses. A two-level full factorial design was performed to optimize the decomposition parameters. Under optimum conditions, both procedures led to low dissolved carbon content (< 11% w.w-1) employing 2 mol. L-1 HNO3. Nevertheless, the closed block presented smaller analytical throughput with approximately 11 digested samples h-1 against 20 samples h-1 for MW. Both procedures showed accuracy for Ca, K, P, Na, and Zn and precision with RSD < 10%. The limits of detection ranged from 2.2 (P) to 16 μg g-1 (Ca) (microwave) and 0.8 (K) to 14 μg g-1 (Na) (closed block). The validated procedures were employed to analyze buffalo mozzarella, minas frescal, Ricotta, Coalho, and cottage cheeses. Based on the nutritional analysis, the type of cheese influenced the variation in nutrient content. Furthermore, for all types of cheese, a discrepancy (p < 0.05) was observed between concentrations for at least one analyte, confirming the lack of uniformity in nutritional composition. The recommended daily intake evaluation demonstrated that all samples of buffalo mozzarella and minas frescal cheese analyzed could be considered sources of Ca and P.

Magnetic solid phase extraction as a nonchromatographic method for the quantification of ultratrace inorganic arsenic in rice by inductively coupled plasma-optical emission spectrometry (ICP OES)

An alternative analytical method was developed for the quantification of inorganic arsenic (iAs) in rice by ICP OES. Iron nanoparticles modified with an organophosphorus compound were used as the solid phase for MSPE of iAs from the plant matrix. The MSPE procedure was performed using 4 mL of a buffer solution with pH 4.0, 20 mg of the nanomaterial, and a 15-min extraction time. The total As (tAs) by ICP OES was also quantified using the same MSPE procedure after solubilization of the samples by a block digester. The accuracy of tAs and iAs quantification was verified using CRM NIST 1568b (97 % and 101 % recovery, respectively). The precision (RSD < 15 %) and LOD and LOQ (1.08 and 3.70 µg kg−1, respectively) of the proposed method were satisfactory. The rice samples had tAs contents between 0.090 and 0.295 mg kg−1 and iAs mass fractions between 0.055 and 0.109 mg kg−1.

Effect of Thermal Treatments on Selected Minerals and Water Soluble Vitamins of Chicken Breast Meat

The study was conducted to ascertain the effect of thermal treatments on selected minerals (Ca, K, Mg, Na, P, Fe and Zn) and water soluble vitamins (B1, B2, B3, B6, B9, B12 and C) contents of chicken breast meat. Industrial skinless chicken breast meat samples were purchased, transported to Bioprocess laboratory in cool conditions, frozen and sliced into dimensions and thawed. The samples were cooked by air frying (AF), baking (BK), deep fat frying (DF) and grilling (GR) at 170, 180 and 1900C for 0, 4, 8 and 12 min for minerals and 0, 8 and 16 min for vitamins. Thereafter, cooked and raw samples were wet acid digested overnight and 5 h digested on a block digester on slowly increased temperature to 1200C, cooled and deionized. The mineral elements were analysed by Optima 4300DV inductivity coupled plasma optical emission spectrometry (ICP-OES) and inductivity coupled plasma mass spectrometry (ICP-MS). These mineral elements were extrapolated through a calibration curve between intensity and concentration, while the vitamins were ascertained by measurement of absorbance of filtrates of the samples dissolved in their respective solvents in the Spectrophotometer against their blank samples at different wavelengths. The results showed that cooking methods decreased significantly (p &lt; 0.05) the mineral elements with an exception of Zn cooked by grilling (GR) that increased by 19.92% and Mg that increased in the cooking methods. The ascending percentage reduction of minerals in cooked chicken breast were Zn, P, K, Fe, Na and Ca. Samples cooked by DF had significantly (p &lt; 0.05) higher percentage reduction of 45.06% in Ca, 27.74% in Na and 18.85% in Zn and higher percentage increases of 14.96% in Mg contents than other methods. Also samples cooked by DF had higher percentage reductions of 55.10%, 37.93%, 37.11%, 34.44% and 30.99% in vitamins B1, C, B2, B9 and B6 Whereas higher percentage reductions of 41.67% and 37.84 % in vitamins B12 and B3 occurred in baking (Bk) and grilling (GR) treated samples. Cooking at 1900C had higher percent reduction in the Ca, Na, Fe, K, P and Zn as well as B1, B12, B2, C, B3, B9 and B6. Cooking methods, temperatures and times decreased significantly (p &lt; 0.05) vitamins and minerals contents of chicken breast meat with an exception of Mg. Samples cooked at 1700C for 4 min and 1700C for 8 min had lower losses of minerals and vitamins compared to similar samples cooked at 1800C and 1900C. The AF cooking method had the least percent reduction of 22.50% than other cooking methods BK (26.88%), DF (36.04%) and GR (30.69%) in vitamin contents.

Potentially Toxic Elements in Costume Cosmetics Used by Children and Adults Are Associated with Cancer Risk.

(1) Background: Costume cosmetics, such as face paints and pancakes, are used by adults and children during Halloween, Carnival, or children's parties. However, the metallic-based pigments used as dyes in these products may contain toxic elements associated with different levels of exposure. Objectives: (a) to determine the Al, As, Ba, Cd, Co, Cr, Cu, Ni, Pb, Sb, Sn, and Sr concentrations in face paints and pancakes; and (b) to estimate cancer and non-cancer risks posed by the concentrations of each element in these products for dermal and ingestion exposure scenarios during children and adult use. (2) Methods: A total of 95 samples of face paints and pancakes (four brands in different textures and colors) were purchased at the largest high-street commercial center in São Paulo city, Brazil. An extraction procedure with nitric acid was carried out using a graphite-covered digester block. Toxic element determinations were performed using an ICP-MS. (3) Results: The non-cancer risks estimated were lower than 1, except for dermal exposure in adults for some target systems. High cancer risk values raise concerns in both groups. The risk for children ranged from 10-8 to 10-5 and proved higher in cases of accidental exposure by ingestion. For occupational exposure in adults, cancer risks were even higher, ranging from 10-3 to 10-5, with the highest values associated with dermal exposure. (4) Conclusions: The study results suggest the presence of potentially toxic elements (PTEs) in cosmetics should be regulated/monitored to protect human health, especially for occupational exposure and use by children.

Multielement determination (essential and potentially toxic elements) in eye shadows exposed to consumption in Brazil using ICP OES.

Worldwide, cosmetics (especially eye shadows) are widely consumed and have a great impact on the economy. The aim of this study was to determine the multielement composition, focusing on essential and potentially toxic elements, in cosmetics (eye shadow) exposed to consumption in Brazil. Concentrations of 17 elements (Al, As, Ba, Cd, Co, Cr, Cu, Mn, Mo, Ni, Pb, Sb, Se, Sr, Ti, V and Zn) were determined in samples (produced in China and Brazil) using a sequential optical emission spectrometer with inductively coupled plasma (ICP OES) after acid digestion, assisted by a closed digester block (6mL of HNO3 + 2mL of H2O2 + 1mL of Triton ×-100 + 1mL of ultrapure water). The method was validated by linearity, precision, accuracy, limits of detection (LoD) and quantification (LoQ). The elements were quantified (in µg g-1): Al (852-21,900), Ba (3.47-104), Cd (1.70-6.93), Cr (< 8.53-66.6), Cu (< 0.480-14.5), Mn (92.20-1,190), Ni (< 4.23-40.7), Pb (< 2.16-5.06), Sb (1.10-10.5), Sr (0.760-46.0), Ti (32.0-440), V (< 0.85-1.7) and Zn (24.90-2,600). As, Co, Mo and Se in all the investigated samples were found to be below the LoQ values of ICP OES. In this study, regardless of sample compositions and origins (Brazilian or Chinese), high levels of Al, Cd, Cr, Cu, Mn, Ni, Pb, Sb, Ti, V and Zn were observed, exceeding the recommended maximum tolerable limits, according to Brazilian and global legislations, which may present potential risks to human health and the environment.

Evaluation of Metal(loids) Concentrations in Soils of Selected Rice Paddy Fields in Malawi

The aim of this study was to obtain baseline data for heavy metal(loids) concentrations of rice paddy fields to evaluate the impacts of soil metal(loids) concentrations on quality of rice, and to identify sources of metal(loids) pollution of paddy fields in Malawi. In total, 66 soil samples were collected from 22 different smallholder rice farmers’ paddy fields (sites) in Malawi. Concentrations of metal(loids) (arsenic (As), cadmium (Cd), cobalt (Co), chromium (Cr), manganese (Mn), lead (Pb), uranium (U), and gallium (Ga)) were measured using inductively coupled plasma mass spectrometry (ICP-MS) after acid block digestion with a mixture of concentrated nitric acid (70% HNO3) and hydrogen peroxide (30% H2O2). Measured soil metal(loids) concentrations were compared with Soil UK CLEA soil metal(loids) guidelines, maximum allowable limits (MAL) recommended by the World Health Organization (WHO), the Chinese Environmental Quality Standards (CEQS) for soil metal(loids) concentrations in agricultural soils, and the normally reported soil metal(loids) concentrations in agricultural fields worldwide. Results indicated that mean soil As (2.2 mg As kg−1), Cd (0.044 mg Cd kg−1), Pb (11 mg Pb kg−1), Co (14 ± 6 mg Co kg−1), Mn (601 mg Mn kg−1), U (2.02 mg U kg−1), and Ga (24 mg Ga kg−1) concentrations were at least three times lower than the respective guidelines and MAL recommended by WHO, UK CLEA, and CEQS (20 mg As kg−1, 0.3 mg Cd kg−1, 32 mg Pb kg−1, 50 mg Co kg−1, and 2000 mg Mn kg−1). The values obtained in this study were also within the normally reported metal(loid) concentrations for unpolluted agricultural soils worldwide. However, the mean Cr concentration (78.0 mg Cr kg−1) obtained in this study was higher than that reported for agricultural soils in China (27 ± 5 mg Cr kg−1; range: 22–39 mg Cr kg−1) but was within the normally reported Cr concentrations (1–100 mg Cr kg−1) for unpolluted soils. These findings suggest that metal(loids) concentrations of Malawian rice paddies pose no threat to production to elevated metal(loids) accumulation in rice, and that rice paddies should be safeguarded from contamination. However, further research is required to investigate the impacts of factors such as source of irrigation of water, water management regimes, soil cation exchange capacity, organic manure/composts amendments, and the application of inorganic fertilizers on uptake, transfer, and translocation of soil metal(loids) to various parts of rice plants, even when the soil metal(loids) concentrations are low.

Effect of losartan potassium, metformin hydrochloride, and simvastatin on in vitro bioaccessibility of Cu, Fe, Mn, and Zn in oat flour from Brazil

BackgroundThe simultaneous administration of drugs with food can compromise the bioaccessibility and absorption of nutrients. The objective of this study was to evaluate the influence of the use of losartan potassium (LP), metformin hydrochloride (MH), and simvastatin (S) on the in vitro bioaccessibility of micronutrients (Cu, Fe, Mn, and Zn) in oat flour from Bahia, Brazil. MethodsThe experimental procedure consisted of the in vitro extraction of the bioaccessible fraction of Cu, Fe, Mn, and Zn in oat flour—with and without LP (50 mg), MH (500 mg), and S (20 mg)—using the unified bioaccessibility method (UBM), simulating the conditions of the gastrointestinal tract. For decomposition of the samples (oat flour and residue), a digester block with a closed system was used. To determine the total content (flour and residual fraction) and bioaccessible micronutrients, inductively coupled plasma optical emission spectrometry (ICP OES) was used. ResultsThe bioaccessible contents (µg g-1) without the addition of drugs were: Cu 5.86 ± 0.21, Fe 32.80 ± 1.32, Mn 87.90 ± 1.90, and Zn 30.33 ± 2.05, with bioaccessibility ranging from 31.5 % for Fe to 99 % for Mn. The in vitro extraction method was validated by mass balance with recovery values from 89.78 % for Cu to 101.94 % for Mn. The range of bioaccessible contents (µg g-1) were: Cu (<4.14), Fe (32.10 ± 0.20–54.10 ± 2.03), Mn (81.40 ± 0.93–93.22 ± 0.80), and Zn (<10.80–29.11 ± 2.20). The estimation of the bioaccessibility of Cu, Mn, and Zn in oat flour were compromised in the presence of LP, MH, and S (p < 0.05). ConclusionChemical interactions can occur between drugs and micronutrients. Taken together, our results highlight that LP, MH, and S can interfere with the bioaccessibility of Cu, Fe, Mn, and Zn in oat flour in patients who use these drugs, suggesting its rational use in further investigations.

Psittaciformes mineral feed analysis method choice and optimization employing chemometric tools

BackgroundIn this work, a multivariated approach based on factorial design and principal component analysis was used to perform the optimization of sample decomposition. The method was applied for the first time to quantify several chemical elements (Ca, Cd, Cr, Cu, Fe, K, Mg, Mn, Na, P, Pb, Se and Zn) in Psittaciformes feed. The choice of the best sample decomposition method is a challenging task considering all variables involved in the process. Generally, this choice is made by using individual monovariated experiments and sometimes interaction effects between these variables as mass of the sample, acid composition, temperature, etc, are not considered. MethodsSample decomposition: 200 mg of sample was mixed with 3.5 mL of HNO3 65% and left at room temperature for 24 h, in a pre-decomposition step, heated at 150 °C for 50 minutes employing a digestion block and mixed with 1.5 mL of H2O2 in the last ten minutes of decomposition. Chemical analysis: A total of 44 samples of Psittaciformes feed digests, among extruded feed, flour and snacks), purchased at pet stores or similar stores in six states in Brazil, were analyzed by inductively coupled plasma optical emission spectrometry (ICP OES). Method accuracy was assessed using certified reference materials SRM 1567a, SRM 1573a, SRM 1577b and IMEP 19. ResultsThe limits of detection (LoD) and quantification (LoQ) ranged from 0.02 mg kg−1 to 0.07 mg kg−1 (Se) and from 1.79 mg kg−1 to 5.41 mg.kg−1 (Ca), respectively. The concentration of chemical elements in animal food ranged from <0.27 mgkg −1 (Fe) to 41.4 ± 2.9 g kg−1 (P), in flour concentrations ranged from <0.05 mg kg−1 (Mg) to 23.8 ± 4.1 g kg−1 (P) and concentrations ranged from <0.05 mg kg−1 (Mn) to 6.8 ± 0.9 g kg−1 (Ca) in snacks. ConclusionThe approach based on multivariate analysis to perform a sample decomposition was successfully applied for Psittaciformes feed. In general, the chemical elements listed on the product labels (Ca, Cd, Cr, Cu, Fe, K, Mg, Mn, Na, P, Pb, Se and Zn) were detected at variable contents when compared to the recommender nutritional values. Toxic elements, Cd and Pb were not detected in any of the analyzed samples. The detection and quantification of chemical elements not listed in nutritional tables and in each product label indicates that mineral addition by manufacturers is performed without considering the chemical composition of the raw materials used in the production process, which can lead to nutritional issues. Thus, a broad revision of Brazilian Legislation concerning product classification considering quality and mineral addition criteria in daily animal feed, especially pets, is urgently required.

Variation of Nutrient Value in Selected Composted Farm Wastes

Smallholder farming is promoted for its environmental friendliness, assurance of food security sovereignty and conservation of indigenous knowledge. However, in actual practice, Smallholder farmers recycle farm plant waste to improve soil fertility. By so doing, they contribute to environmental pollution, emissions, and global warming. This situation is a Smallholder farmers’ challenge worldwide. One of these challenges is the inability to find cheaper sources of plant nutrients. These sources of nutrients are associated with environmental pollution, such as the release of Methane. This study focused on farm wastes (bean trash, maize trash, banana trash, cattle slurry, goat slurry, and pig slurry) commonly produced by smallholder farmers in two farming systems of Masaka and Lyantonde Districts to explore the effects of composting and surface decomposition on nutrients contained in farm wastes by specifically: estimating baseline nutrient contents in farm wastes before disposal, determining the variation of nutrients of farm wastes managed by composting and surface decomposition and the potential source of major nutrients among selected farm wastes. Through carbon analysis, Calorimetric determination of Nitrogen and Phosphorus analysis using a block digester and UV-Visible spectrometer, Carbon, Nitrogen, Potassium and Phosphorus were determined from bean trash, maize trash, banana trash, cattle slurry, goat slurry, and pig slurry. Results revealed that goat slurry, chicken waste, maize trash and pig slurry contained more and retained more P, K, C and N, respectively, as compared to other farm wastes. Significant volumes of N and P were retained in composted materials as compared to those managed by surface decomposition.

Determination and multivariate evaluation of the mineral composition of red jambo (Syzygium malaccense (L.))

This work aimed to evaluate the mineral composition of twelve samples of red jambo (Syzygium malaccensis) collected in 10 cities in the state of Bahia. The samples were digested in a digester block with a reflux system and cold finger, and the analytes were determined by optical emission spectrometry with inductively coupled plasma. The accuracy of the method was confirmed by analyzing NIST 1570a certified reference material (spinach leaves) at a 95% confidence level. The results were evaluated through Principal Component Analysis and Hierarchical Cluster Analysis, which allowed the identification of outliers in the results of the city of Jaguaquara. The analyte concentrations in the samples (mg 100 g –1) comprised a range of: Ca (3.0–28.9), Fe (0.035–0.125), K (134.8–197.5), Mg (2.7–19.8), Mn (0.012–0.131), Na (0.5–10.8), P (0.24–13.5), Sr (0.010–0.314), and Zn (0.026–0.129). This demonstrates that the fruit can be indicated as a potential nutritional supplement in human nutrition.

Levels of selected metals in teff grain samples collected from three different areas of Ethiopia by microwave plasma-atomic emission spectroscopy

The levels of selected essential and non-essential metals in the white, red, and mixed teff grains collected from Bure, Debre Markos and Bahir Dar (Ethiopia) were determined by microwave plasma-atomic emission spectroscopy (MP-AES). After proper sample pretreatment, the powdered teff was wet digested with the acid mixture (5 mL HNO3:1 mL HClO4) at 240 oC for 2:30 h over Kjeldhal digestion block. The accuracy of the optimized procedure was evaluated by analyzing the digest of the spiked samples with a standard solution of metals, and the percentage recoveries varied from 92% to 104%. The mean concentrations of metals determined (mg/kg, dry weight) were in the ranges of Al (713-1513) &gt; Fe (252-1195) &gt; Ca (233-348) &gt; Zn (69-102) &gt; Mn (20-45) &gt; Cu (13-15) &gt; Pb (1.8-2.8) &gt; Cd (0.8-1.8). In this study, Al and Cd were determined in the teff for the first time. Analysis of variance indicated no significant difference between the mean concentrations of Cu and Mn among the white teff samples, Mn among the red teff samples and Cd and Pb among the mixed teff samples, but there was a significant difference for the other studied metals among the corresponding teff samples at 95% confidence level.&#x0D; &#x0D; KEY WORDS: Teff grain, Eragrostistef (Zucc.) Trotter, Essential metals, Non-essential metals, Ethiopia&#x0D; &#x0D; Bull. Chem. Soc. Ethiop. 2020, 34(3), 449-462.&#x0D; DOI: https://dx.doi.org/10.4314/bcse.v34i3.2

Optimization of operational ICP OES parameters and application to PM10 monitoring associated to sugarcane burning

An inductively coupled plasma optical emission spectroscopy (ICP OES) method was developed for the determination of several metals (As, Ba, Ca, Cr, Cu, Fe, K, Mg, Mn, Ni, Sr, Ti, V, and Zn) in particulate matter (PM10) after acid extraction using a digester block. A complete 24 factorial design was employed to explore the best conditions for ICP OES radiofrequency (RF) power, plasma argon flow (P), auxiliary argon flow (A), and carrier argon flow (N). Subsequently, figures of merit consisting of linearity, limits of detection and quantification (LOD and LOQ), and precision (recovery percentages) were evaluated by using the certified reference material (CRM) NBS-SRM-1633a Coal Fly Ash. Findings indicate that the optimum conditions for metal determinations in PM10 by ICP OES are RF = 1200 W; P = 10 L min−1; A = 0.60 L min−1, and N = 0.5 L min−1. Under these optimized conditions, recovery values for the metals detected in the CRM ranged from 81% for Ni to 133% for Fe, with LODs and LOQs between 0.02 ng m−3 and 0.06 ng m−3 for V and 37.1 ng m−3 and 122 ng m−3 for K, respectively, and relative standard deviation (RSD) values lower than 5%, indicating that the proposed optimization provides good accuracy and precision. This methodology was then applied to PM10 samples collected at Campos dos Goytacazes (Rio de Janeiro) during the sugarcane harvest of 2016/2017, in order to assess sugarcane burning impacts on local air quality.

CHEMOMETRIC STRATEGY FOR OPTIMIZATION OF AN ACID DECOMPOSITION METHOD TO DETERMINE THE MINERAL COMPOSITION IN ALMOND PULP (Terminalia catappa Linn.)

In this work, multivariate optimization techniques were applied to develop an acid digestion procedure in digester block using “cold finger” as reflux system to determine minerals in almond pulp samples by inductively coupled plasma optical emission spectrometry. Two-level full factorial design and Box-Behnken design were applied to evaluate and optimize the factors involved in the acid digestion process. In both experimental designs, Function D and Function MR multiple responses were used to establish the method condition for all analytes and with greater digestion efficiency. Two apple and spinach leaves certified reference materials were analyzed to confirm the proposed method accuracy. The digestion efficiency was evaluated by residual carbon content which showed 1.32-1.77% range. The concentration values found for each element in almond pulp collected in Salvador, Bahia, Brazil in mg 100 g-1 were: 3.08 (Ca), 0.209 (Cu), 0.407 (Fe), 356 (K), 21.5 (Mg), 0.096 (Mn), 34.4 (P) and 0.289 (Zn). The developed method was simple and efficient for almond pulp mineral composition evaluation. This unconventional fruit has nutritional relevance with future application for new food recipes and pharmaceutical products formulation.