Wojciech Szwerc

Serum and urinary selenium levels in obese children: a cross-sectional study

OBJECTIVE To determine serum and urinary selenium (Se) levels in children with and without obesity, and to assess if Se influences the risk of obesity. SUBJECTS AND METHODS High-resolution-continuum source-atomic absorption spectrometry (HR-CS-AAS) was used to determine the content of Se in 80 children (age 6-17; 40 boys, 40 girls). Correlations between variables were tested with the use of Spearmans correlation coefficient. U Mann-Whitney test was applied to assess the difference of Se contents in samples. Measured metabolic risk factors (blood pressure, glucose level, triglycerides (TG), low-density lipoprotein (LDL), high-density lipoprotein (HDL), and total cholesterol), age, gender, and BMI were correlated. Logistic regression models were fitted to identify predictors of obesity interacting with selenium content in serum and urine, separately. RESULTS Obese children, regardless of gender, had lower Se content. Se level in serum (p=0.001, OR 0.74, 95%CI 0.62-0.88) and total cholesterol (p=0.001, OR 1.19, 95%CI 1.08-1.31) were the independent factors significantly influencing the risk of obesity in children. Two separate models were observed for Se in urine: (i) Se level (p<0. 0001, OR 0.70, 95%CI 0.58-0.84) and glucose level (p<0.0001, OR 1.22, 95%CI 1.10-1.35), and (ii) Se level (p=0.002, OR 0.60 95%CI 0.43-0.83) and total cholesterol level (p=0.003, OR 1.16, 95%CI 1.05-1.28). CONCLUSION The current study suggests a possible role of Se in obesity. Further research needs to be performed to check if obese children are an at-risk group for Se deficiency.

Biofortification of soy (Glycine max (L.) Merr.) with strontium ions.

Soy (Glycine max (L.) Merr.) is an annual plant cultivated worldwide mostly for food. Moreover, due to its pharmacological properties it is widely used in pharmacy for alleviating the symptoms of osteoporosis. The aim of the present study was to investigate the biofortification of soy treated with various concentrations of strontium. Soy was found to have a strong capacity to absorb Sr(2+) (bioconcentration factor higher than 1). A positive linear correlation (R(2) > 0.98) between the amount of strontium in the growth medium and its content in the plant was also observed. Moreover, at a concentration of 1.5 mM, strontium appeared to be nontoxic and even stimulated plant growth by approximately 19.4% and 22.6% of fresh weight for shoots and roots, respectively. Our research may be useful to obtain vegetable products or herbal preparations containing both phytoestrogens and strontium to prevent postmenopausal osteoporosis.

Optimization of high-resolution continuum source graphite furnace atomic absorption spectrometry for direct analysis of selected trace elements in whole blood samples

Trace analysis plays an important role in medicine for diagnosis of various disorders; however, the appropriate sample preparation is required mostly including mineralization. Although graphite furnace atomic absorption spectrometry (GF AAS) allows the investigation of biological samples such as blood, serum, and plasma without this step, it is rarely used for direct analysis because the residues of the rich organic matrix inside the furnace are difficult to remove and this may cause spectral/matrix interferences and decrease the lifetime of the graphite tube. In our work, the procedure for determination of Se, Cr, Mn, Co, Ni, Cd and Pb with the use of the high resolution continuum source GF-AAS technique in whole blood samples with minimum sample pre-treatment was elaborated. The pyrolysis and atomization temperature as well as the time of signal integration were optimized to obtain the highest intensity and repeatability of the analytical signal. Moreover, due to the apparatus modification, an additional step was added in the for graphite furnace temperature program with minimal argon flow and maximal flow of air during pyrolysis stage to increase the oxidative condition for better matrix removal. The accuracy and precision of the optimized method was verified using certified reference material (CRM) Seronorm Trace Elements Whole Blood L-1 and the developed method was applied for trace analysis of blood samples from volunteer patients of the Orthopedics Department.

The influence of metallic impurities on the free silanol activity of commercial thin-layer chromatography adsorbents demonstrated by retention changes of basic/amphoteric compounds such as peptides

In our previous papers, we have mentioned some specific disruption of peptide zones shape and chromatogram distortion, when using mobile phase containing ion-pairing acids. This problem is investigated here. It concerns not only some specific separation conditions but also various separation systems with silica-based adsorbents and water—alcohol mobile phases. We show that the problem results from significant amount of metallic impurities present in the adsorbents investigated. Our results prove that these impurities strongly affect the activity of free silanol groups and thus the retention of basic or amphoteric compounds and the quality of the results obtained. The standard method of washing adsorbent layer with methanol is not effective against the impurities. Washing chromatographic plates with a solution containing an acid significantly reduces the amount of metallic impurities in the adsorbent, resulting in the reduction/elimination of these adverse effects. However, it also leads to the increase of heterogeneity of acidic groups activity and deterioration of separation system efficiency. Therefore, removing metal ions from the adsorbent may not always be advantageous. Avoiding of use of strong ion-pairing acids is also problematic and not always possible. Thus, the production of high-purity silica of homogenous activity seems to be the best and the most reliable solution of the problem described.

Silica Modified with Polyaniline as a Potential Sorbent for Matrix Solid Phase Dispersion (MSPD) and Dispersive Solid Phase Extraction (d-SPE) of Plant Samples

Polyaniline (PANI) is one of the best known conductive polymers with multiple applications. Recently, it was also used in separation techniques, mostly as a component of composites for solid-phase microextraction (SPME). In the present paper, sorbent obtained by in situ polymerization of aniline directly on silica gel particles (Si-PANI) was used for dispersive solid phase extraction (d-SPE) and matrix solid–phase extraction (MSPD). The efficiency of both techniques was evaluated with the use of high performance liquid chromatography with diode array detection (HPLC-DAD) quantitative analysis. The quality of the sorbent was verified by Raman spectroscopy and microscopy combined with automated procedure using computer image analysis. For extraction experiments, triterpenes were chosen as model compounds. The optimal conditions were as follows: protonated Si-PANI impregnated with water, 160/1 sorbent/analyte ratio, 3 min of extraction time, 4 min of desorption time and methanolic solution of ammonia for elution of analytes. The proposed procedure was successfully used for pretreatment of plant samples.

Assessment of Concentration Changes of Selected Elements in Birch Sap, Depending on Collection Day, Using Atomic Absorption Spectrometry

Abstract Research on new products made of naturally occurring substances that possess regenerative and recuperative characteristics of benefit to humanity occurs continuously. In light of this, birch sap is receiving more and more attention. The aim of this work was an assessment of concentration changes of selected elements in birch sap depending on the day of collection. Herein, we utilized a ContrAA 700 high-resolution atomic absorption spectrometer with continuous light source (HR-CS-AAS) and we applied electro-thermal and flame techniques. Our results indicate that the concentration of the marked elements is variable and is connected with the date of collection. For most of elements, a downward trend can be observed. Only the amount of iron increased with time

Carlina vulgaris L. as a Source of Phytochemicals with Antioxidant Activity

The methanol extracts from three populations of Carlina vulgaris L. were examined for the chlorogenic acid content, mineral content, total phenolic content (TPC), total flavonoid content (TFC), and antioxidant activity. Two populations originated from natural nonmetallicolous habitats (NN (populations from Nasiłów) and NP (populations from Pińczów)), and one metallicolous population (MB) was collected from Bolesław waste heap localized at the place of former open-cast mining of Ag-Pb and Zn-Pb ores dating back to the 13th century and 18th century, respectively. The level of Zn, Pb, Cd, Fe, Ni, and Mn was significantly higher in the root and leaves of MB plants as a result of soil contaminations compared to those of the NN and NP ones. The highest antioxidant potency has been showed by the plants growing in a nonmetallicolous habitat. The flower head extracts obtained from the nonmetallicolous populations also contained the largest amount of chlorogenic acid, whereas the lowest was determined in the roots (ca. 2–3.5 mg/g and 0.2–0.4 mg/g of air-dry weight, resp.). These studies provide important information on the influence of a habitat on the quality of herbal materials and the content of the biologically active primary and secondary metabolites.

Application of atomic absorption spectrometry with continuous light source to analyze selected metals important for human health in different parts of oranges

ABSTRACT The publication describes the application of high-resolution continuum source atomic absorption spectrometry (H-R CS AAS) to determine some physiologically essential and toxic elements occurring in citrus fruits of different origins. Before analysis, the samples were mineralized using a mixture of deionized water and 69% nitric acid 3:1 (v/v) in high pressure microwave digestion at 188°C during one hour. The obtained validation parameters for AAS such as high linearity (the correlation coefficient R > 0.997) and high precision expressed as relative standard deviation (%RSD) were satisfactory for quantification. Cadmium at concentration range from 0.29 to 0.43 mg/kg was determined in all tested samples, however the obtained values did not exceed Polish standards. The higher concentration of potassium comparing to sodium and calcium was noted in each investigated samples. The highest variation was observed for calcium, its concentration strongly depended on the country of origin.