Background: The paper presents the development, validation, and evaluation of measurement uncertainty of a method for quantitative determination of essential and nonessential elements in medicinal plants and their aqueous extracts by using inductively coupled plasma optical emission spectrometry. Methods: The detailed validation of the analytical procedure and calculation of the measurement uncertainty budget allowed the recognition of the methods' critical points.

BackgroundThe metals bioavailability in soils is commonly assessed by chemical extractions; however a generally accepted method is not yet established. In this study, the effectiveness of Diffusive Gradients in Thin-films (DGT) technique and single extractions in the assessment of metals bioaccumulation in vegetables, and the influence of soil parameters on phytoavailability were evaluated using multivariate statistics. Soil and plants grown in vegetable gardens from mining-affected rural areas, NW Romania, were collected and analysed.ResultsPseudo-total metal content of Cu, Zn and Cd in soil ranged between 17.3-146 mg kg-1, 141–833 mg kg-1 and 0.15-2.05 mg kg-1, respectively, showing enriched contents of these elements. High degrees of metals extractability in 1M HCl and even in 1M NH4Cl were observed. Despite the relatively high total metal concentrations in soil, those found in vegetables were comparable to values typically reported for agricultural crops, probably due to the low concentrations of metals in soil solution (Csoln) and low effective concentrations (CE), assessed by DGT technique. Among the analysed vegetables, the highest metal concentrations were found in carrots roots. By applying multivariate statistics, it was found that CE, Csoln and extraction in 1M NH4Cl, were better predictors for metals bioavailability than the acid extractions applied in this study. Copper transfer to vegetables was strongly influenced by soil organic carbon (OC) and cation exchange capacity (CEC), while pH had a higher influence on Cd transfer from soil to plants.ConclusionsThe results showed that DGT can be used for general evaluation of the risks associated to soil contamination with Cu, Zn and Cd in field conditions. Although quantitative information on metals transfer from soil to vegetables was not observed.

The aim of this study was to determine the content of the main essential trace (Co, Cr, Cu, Mn, Se and Zn) and toxic (As, Cd, Hg and Pb) elements in milk by inductively coupled plasma-mass spectrometry (ICP-MS) and cold vapor atomic fluorescence spectrometer (CV-AFS) following priory microwave-assisted digestion with HNO3-H2O2. The milk samples were collected from local small-scale producers of different parts of Rodnei Mountains, Eastern Carpathians, Romania. Mean concentrations in g/L ww were 1.02 (As), 1.09 (Cd), 1.06 (Hg), 6.57 (Pb), 3.54 (Co), 4.56 (Cr), 47.5 (Cu), 23.4 (Mn), 22.3 (Se) and 2985 (Zn). The studied essential trace elements were found to have good and healthy contribution to daily nutrition of consumers in accordance to Recommended Dietary Allowance (RDA). The levels of toxic trace elements (As, Cd, Hg and Pb) were found in very low and concentrations and did not represent any risk to consumers. In addition, some element concentrations of raw milk showed a seasonal pattern: Cu and Zn had higher level in the summer, while As and Mn were more abundant in the winter.

The objective of this study was to determine the chemical composition of five different food seeds (sunflower, poppy, hemp, flax and sesame) regarding fatty acid, mineral (Fe, Cu, Zn, Na, Mg, K, Ca, Al) and protein content. In addition, the total antioxidant capacity of the seeds was evaluated using the photochemiluminescent assay. The food seeds were subjected to lipid extraction and converted into fatty acid methyl esters before the gas chromatography analysis. In all food seeds, the saturated (SFAs), monounsaturated (MUFAs) and polyunsaturated fatty acids (PUFAs) were identified, respectively. PUFAs were the most abundant fatty acids (61.2% ± 0.07% and 84.8% ± 0.08% of total fatty acids), with the highest content in flax and hemp seed oil. Also, high amounts of omega-3 from PUFAs were determined in flax and hempseed oil. Based on the obtained results the sunflower, sesame and poppy seeds are good sources of omega-6, while flax and hemp seeds are good sources of omega-3. All samples are rich in minerals (Na, K, Ca, Mg) and have more than 20% protein content.

Natural zeolites are hydrated aluminosilicate minerals that, due to their remarkable physical-chemical properties of being molecular sieves and cation exchangers, have applications in different areas such as environmental protection, catalysis, animal feed, and dietary supplements. Since natural zeolites may contain traces of undesirable compounds such as toxic metals, the accurate quantification of these elements is necessary. In this study, a direct method for Hg determination in zeolite samples based on the thermal desorption atomic absorption spectrometry (TD-AAS) technique is fully validated, taking into account the legislative requirements in the field. The chosen quantification limit was 0.9 µg kg−1, which is satisfactory for intended use. Trueness was evaluated by recovery rate using certified reference materials containing mercury, with satisfactory results. Other figures of merit, such as repeatability and measurement uncertainty, also fulfill the legislative requirements related to the analysis of dietary supplements. This paper presents, for the first time, a fully validated method for mercury determination in zeolite samples, and the obtained results reveal that the method can be applied successfully for the intended purpose.