Optimization of simultaneous determination of metals in commercial pumpkin seed oils using inductively coupled atomic emission spectrometry

Quantitative determination of selected elements in infant baby formulae and baby food cereals commercially available in Serbia using the ICP OES method

The aim of this paper was the quantitative determination of some macro and trace elements, especially potentially toxic elements in the samples of infant baby formulae and baby food cereals commercially available in Serbia using the inductively coupled plasma optical emission spectrometry (ICP OES) method. Among the macro elements, K is the most abundant in all infant formulae samples, followed by Ca, P, Na and Mg. On the other hand, the analysis of food cereals showed that P is presents in the highest contents, followed by K, Ca, Na, and Mg. Potentially toxic elements As, Pb, Hg, and Cd were not detected in any sample of infant formulae, while Cd was detected and quantified in cereal foods. Also, the calculated values of Estimated Tolerable Weekly Intake (ETWI) as well as the Estimated Tolerable Monthly Intake (ETMI) were lower than recommended values for a tolerable weekly intake (TWI) and provisional tolerable monthly intake (PTMI).

Laser-Induced Breakdown Spectroscopy Combined with Nonlinear Manifold Learning for Improvement Aluminum Alloy Classification Accuracy

Laser-induced breakdown spectroscopy (LIBS) spectra often include many intensity lines, and obtaining meaningful information from the input dataset and condensing the dimensions of the original data has become a significant challenge in LIBS applications. This study was conducted to classify five different types of aluminum alloys rapidly and noninvasively, utilizing the manifold dimensionality reduction technique and a support vector machine (SVM) classifier model integrated with LIBS technology. The augmented partial residual plot was used to determine the nonlinearity of the LIBS spectra dataset. To circumvent the curse of dimensionality, nonlinear manifold learning techniques, such as local tangent space alignment (LTSA), local linear embedding (LLE), isometric mapping (Isomap), and Laplacian eigenmaps (LE) were used. The performance of linear techniques, such as principal component analysis (PCA) and multidimensional scaling (MDS), was also investigated compared to nonlinear techniques. The reduced dimensions of the dataset were assigned as input datasets in the SVM classifier. The prediction labels indicated that the Isomap-SVM model had the best classification performance with the classification accuracy, the number of dimensions and the number of nearest neighbors being 96.67%, 11, and 18, respectively. These findings demonstrate that the combination of nonlinear manifold learning and multivariate analysis has the potential to classify the samples based on LIBS with reasonable accuracy.

Trace element content in commercial complementary food formulated for infants and toddlers: Health risk assessment

The study aimed to analyze trace elements content in baby purees and fruit juices and to evaluate the health risk of young children. The average daily dose, hazard quotient, hazard index and total diet hazard quotient were calculated to assess the potential health risk on per capita and consumers only groups of infants and toddlers. There was no significant health risk for studied groups regarding the intake of trace elements via purees and juices consumption. Health risk for lead was not estimated since the oral reference dose for this metal was not yet established and PTWI value was withdrawn. The average daily dose of lead for infants (0.32 - 0.46 µg/kg bw/day) and toddlers (2.01 - 2.29 µg/kg bw/day) were in accordance with the daily lead exposure intervals estimated by EFSA. Applying statistical analysis, the products were classified into three groups according to the content of trace elements.

A vessel-inside-vessel microwave-assisted digestion method based on SO3 generation in situ for the mineral determination of fatty samples

Vessel-inside-vessel microwave-assisted acid digestion was developed for the analysis of samples with high-unsaturated fat content. For the first time, thermal decomposition of (NH₄)₂S₂O₈ solutions was evidenced for SO₃ generation in situ and gas-phase modification in pressurized digestion flasks. NMR analysis demonstrated the oxidative effect of SO₃ on olefin double bonds despite incomplete mineralization of oil samples. In this context, (NH₄)₂S₂O₈ decomposition was used in association with HNO₃ solutions for sample digestion and mineral determination in edible oils (safflower, coconut, flaxseed, and chia). For all oils, dissolved organic carbon (DOC) contents lower than 5% m m^-1 were obtained under optimum conditions: 210 °C with an irradiation time of 40 min, 7.0 mol L^-1 HNO₃ and 2.0 mol L^-1 (NH₄)₂S₂O₈ in 0.9 mol L^-1 H₂SO₄. Thus, a DOC reduction of about 70% was reached compared to digestions using only HNO₃ at the same conditions. Additionally, a time reduction of up to three-fold was achieved compared to typically demanding edible oil digestions. The proposed method allowed the determination of As, Cd, Cr, Mn, Ni, and Pb in edible vegetable oil samples by ICP-MS. Accuracy was evaluated against the reference method, and no significant difference was observed (p = 0.05), with wide linear ranges and good linearity (r ≥ 0.999) and LOD ranging from 0.48 (As) to 2.41 (Cd) μg L^-1.

D-optimal mixture design for the optimization of extraction induced by emulsion breaking for multielemental determination in edible vegetable oils by microwave-induced plasma optical emission spectrometry

A sample pretreatment based on an extraction process by emulsion breaking for multi-element determination in edible oils was developed. The determination of eight trace elements (Al, Ba, Cu, Cr, P, Ni, Ti, and Zn) was carried out by microwave-induced plasma optical emission spectrometry (MIP OES) after the extraction procedure. A D-optimal mixture experimental design was used to obtain the best experimental conditions for the extraction induced by emulsion breaking (EIEB). The proportion of HNO₃ solution, Triton X-100 solution and sample was evaluated in a multivariate manner. The best recovery efficiency was obtained with 1.0 mL of 30% (v/v) HNO₃, 1.0 mL of 30% (w/v) Triton-X 100 and 3.0 mL of the sample. The precisions, established as the relative standard deviation (RSD, %), were better than 2.5% for all analytes. The developed method was applied to the analysis of commercial vegetable oils with low limits of detection and good precision.

Kinetic models of the extraction of vanillic acid from pumpkin seeds

Vanillic acid is used in the food industry and perfumery, and the optimization of its extraction process from the natural source is important for saving time and money. The presence of vanillic acid in pumpkin seeds was proven using HPLC analysis. Computational optimization of the extraction shows that for the concentration of ethanol 40% and solmodul: V/m=20, the optimum condition for the extraction of vanillic acid from pumpkin seeds was 100 min and 450C. The estimation of fitting for each kinetic model to the experimental kinetic data was performed using the root mean square, standard deviation, and the correlation coefficient. Ponomarev model was shown as the most suitable with the highest accuracy among the six considered kinetic models. The enthalpy and entropy changes were positive, while the Gibbs free energy was negative and decreased when temperature increased during the thermodynamic analysis. Therefore, the extraction of vanillic acid from pumpkin seeds was endothermic, spontaneous, and irreversible.

Macro- and microelements in pumpkin seed oils: Effect of processing, crop season, and country of origin

Macro- and microelements in the samples of virgin and cold pressed pumpkin seed oils produced in Croatia through two consecutive crop seasons were determined by inductively coupled plasma-optical emission spectroscopy (ICP-OES). Croatian oils were also compared to oils from Slovenia and Austria in order to assess differences in the element content. Magnesium, potassium, calcium, sodium, selenium, and iron were the dominant elements in all pumpkin seed oils. Their amounts together with barium, strontium, manganese, copper were up to ninefold higher (p ≤ 0.05) in virgin compared to cold pressed pumpkin seed oils. These differences occur due to the different processing conditions which include salt addition, heat treatment, and higher degree of equipment ware out during virgin pumpkin seed oil production. As the sodium level increases with the addition of salt, virgin pumpkin seed oil could be considered its hidden source and producers should pay attention to the amount added. Contents of cobalt, copper, selenium, and thallium significantly differed (p ≤ 0.05) between the two crop seasons. Principal component analysis revealed clear differences between samples with different origin that can be explained by the specifics in the production processes of each country. In comparison with Austrian and Slovenian, Croatian pumpkin seed oils had significantly lower contents of sodium, potassium, calcium, magnesium, and tin while bismuth and selenium were higher.