Microwave-assisted Acid Digestion Research Articles

Novel method for chlorine determination in biofuel lipid feedstock by coupling a total sample introduction system (hTISIS) to an inductively coupled plasma tandem mass spectrometry (ICP-MS/MS)

BackgroundChlorine concentrations above 1 mg kg−1 in lipid feedstocks for biofuel production can generate corrosion issues in the different refining units as well as catalyst deactivation by clogging or fouling. To reach accurate analyses by inductively coupled plasma (ICP) techniques at low concentration levels, dilution in organic solvents rises as a simpler and more straightforward sample preparation methodology than conventional sample decomposition procedures (e.g., microwave-assisted acid digestion). However, matrix effects and the impact of the Cl chemical form on the signal must be overcome to obtain accurate results. ResultsIn this work, the high temperature torch integrated sample introduction system (hTISIS) operated at 350 °C is coupled to an inductively coupled plasma tandem mass spectrometry (ICP-MS/MS) for the determination of Cl in lipid biofuel feedstock samples diluted in xylene and these results are compared with those reported by a conventional sample introduction system. Under optimal conditions of the hTISIS-ICP-MS/MS configuration, matrix effects are efficiently overcome (recovery values ranged from 101 to 104%) as well as the effect of the Cl chemical form on the signal for 6 organochloride compounds. Thus, an external calibration approach can be set to carry out the quantification of this element in real samples. The method is successfully validated, obtaining a good agreement in the Cl concentration reported in a standard reference material (SRM NIST 1634c) and also by comparing the concentration results obtained by external calibration and standard addition approaches in two biofuel feedstock samples. Significance and noveltyThe hTISIS coupled to an ICP-MS/MS system is used for the first time to overcome not only matrix effects but also the impact of the Cl chemical form in biofuel feedstock samples. This novel method, with a limit of quantification (LOQ) of 7.1 μg kg−1, give access to an accurate Cl determination in all kind of lipid feedstocks for clean fuel production.

Determination of Toxic Elements in Cannabinoid and Opioid Drugs and Their Impact on Addicts' Health: A Comparative Study.

Drug addiction is associated with significant health risks, including cardiovascular complications, cancer, and mental disorders. Illicit drugs, such as cannabinoids and opioids, including prescription medications, are widely consumed and have profound health consequences. Understanding the health effects of the toxic elements in these substances is critical for overdose prevention and effective recovery strategies. This study aimed to determine toxic elements, including arsenic (As), cadmium (Cd), mercury (Hg), and nickel (Ni), in cannabinoid and opioid drugs and in biological samples (whole blood, scalp hair, and serum) from 311 male drug abuse patients aged 15-60years with a history of drug abuse. The participants were categorized into three age groups. The comparative analysis involved 113 reference subjects of the same age groups. The sample preparation employed microwave-assisted acid digestion, and the toxic elements were quantified using atomic absorption spectrophotometry. Accuracy was ensured using certified reference materials for hair, whole blood, and serum samples. Drug-addicted subjects had significantly higher concentrations of toxic elements (arsenic, cadmium, mercury, and nickel) in biological samples than referent subjects (p > 0.001). Elevated levels of these toxic elements may increase susceptibility to infections, possibly due to malnutrition, drug-related effects, and additional contaminants. These findings necessitate further studies to explore the long-term health outcomes, potential treatment options, and broader socioeconomic impacts of substance abuse. This study serves as a baseline for future research in this critical public health field.

Spatial distribution of Pb and Zn in soils under native vegetation in Southeast Brazil.

Heavy metals can play an important biological role as micronutrients but also as potentially toxic elements (PTEs). Understanding the natural concentrations of PTEs-Pb and Zn included-in soils allows for the identification and monitoring of contaminated areas and their role in environmental risk assessment. In this study, we aim to determine semi-total or natural and available concentrations of Pb and Zn in topsoils (0-20 cm depth) from 337 samples under native vegetation in the State of Minas Gerais, Brazil. Additionally, we sought to interpret the spatial geochemical variability using geostatistical techniques and quality reference values for these elements in soils were established. The semi-total concentrations were determined by flame and graphite furnace atomic absorption after microwave-assisted nitric acid digestion method. The available concentrations were extracted using the Mehlich-I extractor and determined by atomic absorption spectrometer. Spatial variability was modeled using semivariance estimators: Matheron's classic, Cressie and Hawkins' robust, and Cressie median estimators, the last two being less sensitive to extreme values. This allowed the construction of digital maps through kriging of semi-total Pb and Zn contents using the median estimator, as well as other soil properties by the robust estimator. The dominance of acidic pH and low CEC values reflects highly weathered low-fertility soils. Semi-total Pb contents ranged from 2.1 to 278 mg kg-1 (median: 9.35 mg kg-1) whereas semi-total Zn contents ranged from 2.7 to 495 mg kg-1 (median: 7.7 mg kg-1). The available Pb contents ranged from 0.1 to 6.92 mg kg-1 (median: 0.54 mg kg-1) whereas available Zn contents ranged from 0.1 to 78.2 mg kg-1 (median: 0.32 mg kg-1). The highest Pb and Zn concentrations were observed near Januária, in the northern part of the territory, probably on limestone rocks from the Bambuí group. Finally, the QRVs for Pb and Zn in natural soils were lower than their background values from other Brazilian region and below the prevention values suggested by Brazilian environmental regulations.

Impact of leaching procedure on heavy metals removal from coal fly ash

In this work, removal of heavy metals (Cr, Mn, Co, Ni, Cu, Zn, As, Cd, and Pb) from fly ash has been studied using acid leaching and wet oxidation methods. In parallel, microwave-assisted acid digestion was applied for determination of pseudo-total concentrations of heavy metals to estimate the leaching efficiency. Multivariate statistics (Pearson correlation, principal component analysis, and hierarchical cluster analysis) have shown two dominant groups of elements, depending on their characteristics and affinity towards the ash solid phase. Thus, Cr, Zn, Mn, Co, and Ni belong to the group I, while Pb, As, Cd, and Cu belong to the group II. It was demonstrated that the wet oxidation method was more suitable than acid leaching since the reduction in metal concentration was 30 to 75 % compared to 12 to 25 % obtained by acid digestion. The influence of fly ash treatment on the residue characteristics was investigated by X-ray diffractometry and scanning electron microscopy. The analyses revealed surface and structure changes of fly ash after the wet oxidation treatment. Overall, wet oxidation could be an appropriate treatment for heavy metal removal from fly ash, providing a material that could be further used, thus reducing the risk of pollution caused by the disposal of coal combustion fly ash.

A new ultrasound-assisted microextraction for elemental impurities determination in tablets by ICP-MS according to USP chapters 232 and 233

Along with the United States Pharmacopeia (USP) chapters 232 and 233 regarding elemental impurities in pharmaceutical products, new challenges have been imposed in terms of sample preparation procedures prior to inductively coupled plasma mass spectrometry analysis, considering the matrix complexities. As so, a new microextraction procedure assisted by ultrasound using a cup-horn sonoreactor, minimal reactants, and sample was proposed and validated according to USP. The procedure was optimized with samples of milled tablets and 3 different acid mixtures (HNO3, 3HNO3:1HCl, and 9HNO3:1HF) and it was compared with microwave-assisted acid digestion. In the validation step, recoveries ranging from 85 to 120 % and RSD below 10 % were obtained for 22 analytes (except Ag and Pt) with satisfactory linearity and good sensitivity. The method was then applied for 37 samples of antidepressants, which presented trace levels of As, Ba, Cd, Co, Cr, Cu, Ni, Pb, Pd, Sn, and V.

APMP.QM-S19: Toxic elements in seafood

Main textSeafood is one of the major food resources for human consumption in the world. The CODEX Alimentarius Commission and many jurisdictions have set maximum levels of metallic contaminants in seafood. The use of reliable methods for measurement of metallic contaminants is important in safeguarding the quality of these products and public health.The Supplementary Comparison APMP.QM-S19: Toxic Elements in Seafood was coordinated by the Government Laboratory, Hong Kong, China (GLHK). Four measurands (arsenic, cadmium, mercury and lead) in seafood were chosen. The last CCQM or RMO key comparison / supplementary comparison in the area of metallic contaminants in seafood was organized by GLHK in 2011 (APMP.QM-S5). Hence, it was timely to organize another comparison that covers different measurands. This Supplementary Comparison (APMP.QM-S19) offers different analytical challenges (e.g. in analysis of mercury and a different range of measurands) as compared to the previous comparison. Moreover, it enabled National Metrology Institutes / Designated Institutes (NMIs/DIs) that did not participate in the previous comparisons to demonstrate their measurement competencies.Nineteen institutes participated in APMP.QM-S19. Most participating NMIs/DIs employed microwave-assisted acid digestion for sample dissolution. Inductively coupled plasma mass spectrometry (ICP-MS), including triple quadrupole and sector field, were the most commonly used instrumental techniques. Results of all participating NMIs/DIs were evaluated against the supplementary comparison reference value (SCRV). The SCRV and associated uncertainty were determined from results of NMIs/DIs that participated in the supplementary comparison using methods with demonstrated metrological traceability. Median was used as estimator of the SCRVs. For arsenic, the SCRV was 1.342 mg/kg calculated from 15 participating NMIs/DIs. For arsenic, cadmium, mercury and lead, the SCRVs were 1.342 mg/kg, 0.3630 mg/kg, 0.1230 mg/kg and 0.4101 mg/kg, respectively, calculated from 15, 14, 13 and 11 participating NMIs/DIs.Participating NMIs/DIs that have successfully participated in APMP.QM-S19 have demonstrated measurement capabilities in determining inorganic elements, in a mass fraction range from 0.02 mg/kg to 50 mg/kg in high organic content matrix, including seafood of animal origin and high protein food.To reach the main text of this paper, click on Final Report. Note that this text is that which appears in Appendix B of the BIPM key comparison database https://www.bipm.org/kcdb/.The final report has been peer-reviewed and approved for publication by the CCQM, according to the provisions of the CIPM Mutual Recognition Arrangement (CIPM MRA).

Preparation of Food Samples Using Homogenization and Microwave-Assisted Wet Acid Digestion for Multi-Element Determination with ICP-MS.

Sample preparation is crucial for elemental determination, and various techniques are available, one of which involves homogenization followed by acid digestion. Special care is required during sample handling in the preparation stage to eliminate or minimize potential contamination and analyte loss. Homogenization is a process that simultaneously reduces particle size and uniformly distributes sample components. Following homogenization, the sample undergoes acid digestion, wherein it is digested with acids and auxiliary chemicals at elevated temperatures, transforming solid samples into a liquid state. In this process, metals in the original sample react with acids to form water-soluble salts. Samples prepared through acid digestion are suitable for elemental analysis using techniques such as inductively coupled plasma mass spectrometry, inductively coupled plasma optical emission spectroscopy, atomic absorption spectroscopy, electrochemical methods, and other analytical techniques. This work details the preparation of food samples for multi-element determination using inductively coupled plasma mass spectrometry. The step-by-step procedure involves the homogenization process using a laboratory-sized mixer with ceramic blades, followed by acid digestion in closed vessels using microwave-assisted wet acid digestion. A mixture of 5.0 mL of 68 wt% HNO3 and 1.0 mL of 30 wt% H2O2 serves as an auxiliary reagent. This guide provides an explanation of the processes involved in both stages.

Water-Based Microwave-Assisted Digestion Method for Electrochemical and Chromatographic Determination of Total Fluoride Ions in Toothpaste Samples

Fluoride ions are the major constituents of dental products because they prevent cavities through bacterial growth inhibition. However, excessive consumption of fluoride ions results in fluorosis, thereby causing tooth staining and roughness. Therefore, there is a crucial need to develop rapid and effective methods for monitoring fluoride levels in dental products. The current study describes a greener water-based microwave-assisted digestion (WB-MAD) prior to fluoride-ion-selective electrode (F-ISE) measurement for the determination of fluoride ions in various toothpaste products. The optimum conditions of the developed WB-MAD method were 180 °C digestion temperature, 60 min digestion time, 0.05 g toothpaste amount and 10 mL distilled water. Under the optimum conditions, the method detection limit (MDL) of 0.00302 µg/kg and the method quantification limit (MQL) of 0.01007 µg/kg obtained were favorably comparable with the literature reports. The proposed WB-MAD method was both accurate (99.2 to 101%) and precise (≤0.75%) for the quantitative determination of F− in toothpaste samples using F-ISE. Furthermore, the newly developed WB-MAD method showed better accuracy (97–100%) than the traditional microwave-assisted acid digestion methods (71–92%). It is worth indicating that since water was used as the only digestion reagent, it was possible to validate the F-ISE results with ion chromatography (IC). The percentage recoveries obtained from IC (91–104%) and F-ISE (93–100%) were statistically insignificant. In view of the validation data, the proposed WB-MAD method can be considered as an alternative to the conventional microwave-assisted acid digestion (MAAD) methods for the determination of F− in toothpaste samples containing sodium monofluorophosphate.

Determination of trace elements in ibuprofen drug products using microwave-assisted acid digestion and inductively coupled plasma-mass spectrometry

Trace elements are found in most drugs as a result of the drug formulation and drug production methods. An inductively coupled plasma-mass spectrometry method for the determination of 24 trace elements (Mg, Ti, V, Cr, Mn, Cu, Fe, Co, Ni, Zn, As, Se, Mo, Ru, Rh, Pd, Ag, Cd, Sb, Ba, Ir, Pt, Au, and Pb) in solid ibuprofen tablets was established in relation to the ICH Q3D(R1) guideline, to evaluate the possibility of linking trace elemental profiles to drug formulation strategies, and to differentiate between drug products based on the trace elemental profiles. Ten European ibuprofen drug products were evaluated (n=3). The sample preparation was performed by microwave-assisted acid digestion using only 10 mg of homogenized sample and 900 μL of a mix of 65% HNO3, 37% HCl, and 30% H2O2. Solid residuals primarily composed of insoluble SiO2 excipients were removed by centrifugation. Only concentrations of Mg, Fe, Ti, Mn, Cr, and Ni were detected above the limits of detection and did not exceed the ICH Q3D(R1) guideline permitted daily exposure limits. The trace elemental profiles were evaluated through principal component analysis. Three principal components describing 96% of the variance were useful in grouping the ibuprofen drug products, and the detected trace elemental remnants could be related to drug formulation and drug production strategies. An in-house quality control material was used in lack of certified reference materials and was in combination with spike recoveries used for method validation. Good spike recoveries (94–119%) were obtained for all measured trace elements except Mg. Mg showed acceptable spike recoveries (75–155%) for mid and high-spike concentrations, but poor recoveries (30–223%) were detected with low spike concentrations in spike matrices containing high amounts of Mg. Overall, the method is suggested applicable for solid drugs containing insoluble SiO2 excipients and drugs comparable to ibuprofen.

Geographical origin identification of mandarin fruits by analyzing fingerprint signatures based on multielemental composition

Given rising traders and consumers concerns, the global food industry is increasingly demanding authentic and traceable products. Consequently, there is a heightened focus on verifying geographical authenticity as food quality assurance. In this work, we assessed pattern recognition approaches based on elemental predictors to discern the provenance of mandarin juices from three distinct citrus-producing zones located in the Northeast region of Argentina. A total of 202 samples originating from two cultivars were prepared through microwave-assisted acid digestion and analyzed by microwave plasma atomic emission spectroscopy (MP-AES). Later, we applied linear discriminant analysis (LDA), k-nearest neighbor (k-NN), support vector machine (SVM), and random forest (RF) to the element data obtained. SVM accomplished the best classification performance with a 95.1% success rate, for which it was selected for citrus samples authentication. The proposed method highlights the capability of mineral profiles in accurately identifying the genuine origin of mandarin juices. By implementing this model in the food supply chain, it can prevent mislabeling fraud, thereby contributing to consumer protection.

Elemental Concentrations of Natural Graphite and Steelmaking Slag: Development of Microwave-Assisted Acid Digestion

To develop more sustainable purification and recovery processes, it is critical to accurately determine inorganic impurities of natural graphite (NG) and valuable elements present in low concentrations in steelmaking slag. This study applied three microwave-assisted acid digestion methods for basic oxygen furnace (BOF) slag, NG, and NG ash. Nitric acid (HNO3), hydrochloric acid (HCl), and hydrogen fluoride (HF) were used in method 1. In method 2, method 1 was followed by microwave-assisted boric acid (H3BO3) digestion. In method 3, acids (HNO3, HCl, HF, and H3BO3) were added simultaneously. Concentrations were measured using inductively coupled plasma–optical emission spectrometry. Analytical performance was evaluated using spiking recovery tests (NG) and certified reference (slag) material (CRM). Spiking recoveries for Al, Ca, Fe, K, Mg, Na, and Si were between 5% and 116% (method 1) and 94%–116% (methods 2 and 3). CRM recoveries for Al, Ca, Fe, Mg, Mn, P, Si, Ti, and V were between 2% and 102% (method 1) and 92%–103% (methods 2 and 3). The unsuitability of method 1 was evident due to the low recoveries. Methods 2 and 3 digested Ca- and Si-containing BOF slag completely without visible residue. The sufficient recoveries verified the adequacy of the methods. The suitability of method 3 probably depended on the phases of samples, as quartz was not completely digested from the NG. Method 2 completely digested the inorganic material of NG, and the spiking test showed no loss of volatile silicon compounds. These methods have not been published for NG or NG ash and validated for slag before.

Unraveling the interaction between lead and calcium in occupationally exposed males: an exploratory observation study.

The systemic illnesses associated with chronic lead exposure are partially explained by the interaction between lead and calcium metabolism. Lead exposure is posited to alter calcium levels either by altering calcium homeostasis markers or altering bone remodeling. The present study investigated the interaction between blood lead levels and calcium homeostasis markers and bone remodeling markers among lead-smelting plant workers. Adult male workers employed at the lead-smelting plant were clinically investigated as part of their regular occupational health assessment program. Additionally, control participants without occupational lead exposure, employed in administrative and white-collar jobs were invited to participate in the study. Sociodemographic and occupational details were collected by pre-standardized semi-structured questionnaires from all consenting participants, followed by clinical examination and blood collection. Blood lead levels were estimated using microwave-assisted acid digestion and the inductively coupled plasma mass spectrometry technique. Serum calcium and total protein and alkaline phosphatase levels were estimated as per standard biochemical techniques. 25-hydroxy vitamin-D3, calcitriol, and osteocalcin were estimated using the enzyme-linked immunosorbent assay. In addition to comparative analysis for comparing the two groups, independent linear regression models were explored to investigate the associations between serum calcium and blood lead and osteocalcin levels. A total of 189 lead-exposed men employed at the lead-smelting plant and 25 male control participants consented to participate. The two groups were similar in age, diet, and body mass index. Occupationally exposed individuals exhibited significantly lower serum calcium and higher bone remodeling markers (osteocalcin and alkaline phosphatase) as compared to controls. However, the serum 25-hydroxy vitamin-D3 and calcitriol levels were not significantly different between the two groups. Lastly, the serum lead and osteocalcin were weakly but significantly associated with serum calcium levels after controlling for variations in total protein, diet, 25-hydroxy vitamin-D3, calcitriol, and alkaline phosphatase in the study participants. Current observations reinforce the adverse role of lead exposure on calcium metabolism. Although lead exposure is posited to affect calcium metabolism by multiple pathways, current study observations favor the bone remodeling pathway. The observations recommend periodic screening for calcium and bone health among lead-exposed adults.

Dietary intake and trophic transfer of cadmium and lead from three daily consumption vegetables in Quito, Ecuador

The presence of toxic metals in vegetables of daily consumption is a concern for human health. Little is known about the concentration of toxic metals in vegetables sold in markets in Quito, Ecuador, and the corresponding risk to the population. This study aimed to measure the concentration of cadmium (Cd), and lead (Pb) in tomatoes, carrots, and lettuce, to estimate the risk for human health, and to determine the trophic transfer factor using Drosophila melanogaster flies. Vegetable samples were obtained from four local markets in Quito to measure the concentration of Cd and Pb (expressed in mg/kg of dry weight) in the vegetables by microwave-assisted acid digestion and atomic absorption spectrophotometry. Drosophila melanogaster flies were fed with contaminated vegetables to determine de trophic transfer factor of metals in the trophic chain. Our results showed the highest accumulation of Pb and Cd occurred in lettuce. In all cases, the Pb and Cd concentrations exceeded the maximum levels established by the Food and Agriculture Organization. However, the daily intake of metals and the health risk index showed no risk from daily consumption. Pb’s trophic transfer factor was excessively high in the tomato-fed flies, showing transference and accumulation in the flies. Cadmium concentration in tomato-fed flies was also the highest among the three vegetables. The trophic chain transfer of toxic metals from vegetables to Drosophila has been observed through a high accumulation of these metals in flies, and this suggests a negative impact on both human health and ecosystems.

Elemental analysis and health risk assessment of different hazelnut varieties (Corylus avellana L.) collected from Giresun - Turkey

Corylus avellana L. is one of the most widely grown and traded nuts in the world. There are many types and varieties, and their ingredients are a good source of nutrients in terms of minerals. However, depending on their region and soil structure, they may contain a variety of heavy metals and toxic elements. Mineral element composition and potentially toxic element contents of different C. avellana L. varieties (15 samples) collected from the city of Giresun, which is known as the hazelnut capital of Turkey, were determined by inductively coupled plasma mass spectrometry (ICP-MS) after microwave assisted acid digestion. The elemental composition of hazelnuts is in the following ranges mg kg-1; manganese (Mn): 58.9–193, iron (Fe): 44.1–62.2, zinc (Zn): 27.0–53.8, selenium (Se): 0.01–0.12, chromium (Cr): <0.0004–0.387, copper (Cu): 16.9–25.8, magnesium (Mg): 1132–1327, calcium (Ca): 1264–1899, potassium (K): 5459-6841, sodium (Na): 1.32–7.88, lead (Pb): <0.001, cadmium (Cd): <0.001, nickel (Ni): 0.82–2.52 and arsenic (As): 0.003–0.009. These findings were used to calculate recommended dietary allowance (RDA), target hazard quotient (THQ), hazard index (HI), and carcinogenic risk (CR) values for hazelnuts. Considering the THQ values, it was determined that hazelnuts are safe for consumption by both genders. According to the carcinogenic risk calculation, all of the hazelnuts examined in this study were categorized as moderately risky in terms of Ni contents, and it was concluded that Ni may be the most important element exceeding the risk limit in hazelnuts in general.

Analysis of Eight Types of Plant-based Milk Alternatives from the United States Market for Target Minerals and Trace Elements.

A wide variety of commercial plant-based foods that are marketed and sold as alternatives for milk (plant-based milk alternatives or PBMAs) are available to consumers. In this study, PBMAs from the United States (n=85) were subjected to analysis for target minerals (magnesium, phosphorus, selenium, and zinc) to compare their variability across PBMA types, brands, and production lots. Samples were also screened for the environmental contaminant elements arsenic, cadmium, and lead. The eight PBMA types sampled were produced from almond, cashew, coconut, hemp, oat, pea, rice, and soy. Elemental analysis was conducted using microwave-assisted acid digestion followed by inductively coupled plasma-mass spectrometry. The results showed that pea PBMAs contained the highest mean amounts of phosphorus, selenium, and zinc, while soy PBMAs were highest in magnesium. Mean amounts of minerals were lower than those found in milk for the majority of PBMA types. There was significant variation (P<0.05) in amounts of minerals across the majority of product brands. The amounts of phosphorus and magnesium varied across production lots (P<0.05), but the absolute value of these differences was low. Total arsenic was highest in rice PBMAs; amounts of cadmium and lead across PBMAs were generally found at low or non-quantifiable amounts. These results underscore the importance of generating analytical data on the elemental composition of products within the rapidly growing category of PBMA.

Coordination chemistry applied to anti-doping analysis: Cobalt quantification as its diethyldithiocarbamate complex by liquid chromatography coupled to high resolution tandem mass spectrometry.

Cobalt was included on the World Anti-Doping Agency Prohibited List in 2015 due to its effect on stimulus of erythropoiesis via stabilization of hypoxia-inducible factor. Although it has proven benefits for performance enhancement, the unavailability of inductively coupled plasma-mass spectrometry on routine of the accredited laboratories is a factor that reduces its applicability in anti-doping analysis. Therefore, an analytical method for quantification of urinary cobalt as its diethyldithiocarbamate complex by liquid chromatography coupled with high-resolution tandem mass spectrometry was developed and validated. Palladium was proposed as internal standard and rhodium as a complexation control. A microwave-assisted acid digestion of the urine samples was essential, not only to eliminate the matrix effect but mainly to avoid the non-specific bond of cobalt to endogenous molecules. A linear method was obtained over the studied range from a negative urine control to a spiked concentration of 25 ng/mL, with an estimated limit of quantification of 2.5ng/mL, and an adequate combined standard uncertainty of 11.4%. Considering that all reagents are commercially available, the proposed strategy is feasible to be included on routine sample preparation. Monitoring urinary cobalt concentrations globally opens the perspective to support the anti-doping system to define a suitable threshold value and to understand its potential misuse by athletes seeking for performance improvement.

Selenium bioaccessibility in rice grains biofortified via soil or foliar application of inorganic Se

Selenium (Se) is a micronutrient for humans, and its deficiency is related to various diseases. Recent studies have proposed strategies to increase Se intake, especially using selenium biofortification in staple foods. However, few investigations shed light on the chemical species and the bioavailability of Se in cereal grains, including rice, one of the most important staple foods worldwide. This study aimed to determine the bioaccessible fractions of Se in rice grains biofortified with inorganic Se species using an in vitro sequential extraction method to simulate human digestion. Samples and extracts were submitted to microwave-assisted acid digestion, and total/bioaccessible Se levels were determined by DRC-ICP-MS. Accurate Se quantification was achieved using matrix-matching calibration. Rice biofortification via foliar application increased Se levels in the bioaccessible fraction more effectively than soil applications. Bioaccessible Se represented, on average, 61 ± 5 % of the total levels. Of the total Se content in rice, 44 ± 4 % was extracted in the gastric step, which is where most protein-bound bioaccessible selenium is degraded. Biofortification with inorganic forms of Se effectively increases the bioaccessible content of this element in food. Still, the amount to be applied must be corrected based on the bioaccessible fraction of the nutrient in rice grains.

Multivariate analyses of selected trace elements from Kigelia africana (Lam.) Benth. plant by ICP-OES: A chemometrics approach

AimThe entire world population is increasingly shifting to the use of plant-based medicines either as supplementation or medication. These medicinal plants absorb trace elements and metals available in the soil solutions in ionic, complexed, or chelated forms and can either be deficient or toxic for human and animal consumption. Therefore, screening these medicinal plants for trace elements or metals is important according to the recommendation of WHO and European legislation (1881/2006/EC). MethodologyIn this study, the concentrations of 12 trace elements and metals (Al, B, Ba, Be, Bi, Ga, K, Li, Mg, Se, Te, and Tl) were determined from Kigelia africana leaf and fruit extracts using 700 series Agilent inductively coupled plasma – optical emission spectrometer (ICP-OES) coupled with ultrasonic CETAC U-6000AT+ Nebulizer after microwave-assisted acid digestion of the plant samples with MDS-6G closed microwave digester. ResultsThe study revealed that K. africana extracts have significant trace elements with the fruit extracts having high concentrations of required trace elements (3.2 mgkg−1 Mg, 67.18 mgkg−1 K, 0.04 mgkg−1 Se, and 0.16 mgkg−1 Al). Interestingly, the fruit and leaf extracts also have the required amount of Boron (B), Bismuth (Bi), Gallium (Ga), and Lithium (Li) which are essential in human brain function, nervous system, and glucose metabolism among other therapeutic functions. Barium (Ba), Beryllium (Be), Tellurium (Te), and Thallium (Tl) are known toxic metals when accumulated in the human body and are found in low concentrations in this study. ConclusionThis study revealed that trace elements are positively correlated when analyzed with principal component (PCA) and hierarchical cluster (HCA) analyzes. This shows that K. africana plant extract can be considered one of the most important medicinal plants with several therapeutic benefits. The concentrations of several trace elements according to recommended dietary allowance (RDA) as well as the correlation between these metals and metalloids are reported for the first time using PCA and HCA.

In vitro bioaccessibility of Cd, Cu, Fe and Zn in basil (Ocimum Basilicum L. Grecco a palla) after cadmium intoxication

Cadmium is a toxic element which can be accumulated in the edible parts of plants compromising an entire food chain with serious damage to the living organisms, presenting synergistic and antagonistic effects with the elemental bioaccessibility. In this work, a simulated gastrointestinal digestion was performed to assess the in vitro bioaccessibility of Cd, Cu, Fe and Zn in basil samples after Cd intoxication. The hydroponic cultivation was made in a Hoagland solution at different concentrations (0, 1.5 and 3.0 µmol L-1). Elemental concentration was achieved using a microwave-assisted acid digestion after the growing up of the plants in vermiculite pots by 15 days. The in vitro gastrointestinal procedure was applied in fresh and lyophilized leaves followed by a clean-up step in a sonoreactor cup horn using 1 mL of the extract, 100 µL of HNO3 and 500 µL of H2O2 by 5 minutes. The results showed that Cd bioaccessibility was statistically different at 95% confidence level (p &lt; 0.05) for the lyophilized and fresh leaves samples. The in vitro bioaccessibility increased with concentration in the contamination treatment. Moreover, a high positive correlation was observed between Cd-Fe and Cu-Zn, and a negative correlation between Cd-Zn and Fe-Zn in lyophilized and fresh leaves, respectively, suggesting that the absorption of essential elements was affected by Cd.

Measuring trace element fingerprinting for cereal bar authentication based on type and principal ingredient.

This paper introduces a method for determining the authenticity of commercial cereal bars based on trace element fingerprints. In this regard, 120 cereal bars were prepared using microwave-assisted acid digestion and the concentrations of Al, Ba, Bi, Cd, Co, Cr, Cu, Fe, Li, Mn, Mo, Ni, Pb, Rb, Se, Sn, Sr, V, and Zn were later measured by ICP-MS. Results confirmed the suitability of the analyzed samples for human consumption. Multielemental data underwent autoscaling preprocessing for then applying PCA, CART, and LDA to input data set. LDA model accomplished the highest classification modeling performance with a success rate of 92%, making it the suitable model for reliable cereal bar prediction. The proposed method demonstrates the potential of trace element fingerprints in distinguishing cereal bar samples according to their type (conventional and gluten-free) and principal ingredient (fruit, yogurt, chocolate), thereby contributing to global efforts for food authentication.