Quick method (FT-NIR) for the determination of oil and major fatty acids content in whole achenes of milk thistle (Silybum marianum (L.) Gaertn.).

BACKGROUND: Calibration models for the Fourier transform-near infrared (FT-NIR) instrument were developed for quick and non-destructive determination of oil and fatty acids in whole achenes of milk thistle. Samples with a range of oil and fatty acid levels were collected and their transmittance spectra were obtained by the FT-NIR instrument. Based on these spectra and data gained by the means of the reference method - Soxhlet extraction and gas chromatography (GC) - calibration models were created by means of partial least square (PLS) regression analysis. RESULTS: Precision and accuracy of the calibration models was verified via the cross-validation of validation samples whose spectra were not part of the calibration model and also according to the root mean square error of prediction (RMSEP), root mean square error of calibration (RMSEC), root mean square error of cross-validation (RMSECV) and the validation coefficient of determination (R(2) ). R(2) for whole seeds were 0.96, 0.96, 0.83 and 0.67 and the RMSEP values were 0.76, 1.68, 1.24, 0.54 for oil, linoleic (C18:2), oleic (C18:1) and palmitic (C16:0) acids, respectively. CONCLUSION: The calibration models are appropriate for the non-destructive determination of oil and fatty acids levels in whole seeds of milk thistle.

Effects of subchronic exposure to N,N-diethyl-m-toluamide on selected biomarkers in common carp (Cyprinus carpio L.).

DEET (N,N-diethyl-m-toluamide) is the most common active ingredient in the insect repellents commonly detected in European groundwater. The aim of this study was to investigate the effect of subchronic DEET exposure on biochemical and haematological parameters, antioxidant enzymes, including catalase, glutathione peroxidase, glutathione reductase, and glutathione S-transferase, and the amount of thiobarbituric acid reactive substances (TBARS) in common carp (Cyprinus carpio L.). Two specific proinflammatory and anti-inflammatory cytokine genes were selected to assess an immunological status of the fish. Fish were exposed for 28 days to three concentrations of DEET (1.0 µg/L, 0.1 mg/L, and 1.0 mg/L) where 1 µg/L is corresponding to the concentration found in the environment. DEET had a significant (P < 0.05) effect on increased RBC, decreased mean corpuscular volume (MCV), and mean corpuscular haemoglobin value (MCH) compared to control groups in the concentration of 1 mg/L. A significant decline (P < 0.05) in triacylglycerols (TAG) in plasma was found in the concentration of 1 mg/L compared to the control groups. The parameters of oxidative stress in tissues of common carp were weekly affected and immunological parameters were not affected.

Focusing of alkali earth metals in ligand step gradient.

A capillary electroseparation technique for focusing and selective pre-concentration of metal chelates with subsequent on-line isotachophoresis (ITP) analysis was developed and verified. The ions of alkali earth metals (Mg, Ca, Sr, and Ba) were pre-concentrated from the mixture and analyzed. The focusing of the metals was carried out in a ligand step gradient, which was created by the addition of a convenient ligand agent to the regular stationary pH step gradient. The analytical procedure consisted of three steps. During the first step, the metal ions were electrokinetically continuously dosed into the column where they were selectively trapped on the stationary ligand step gradient in the form of unmoving zones of chelate complexes with effectively zero charge. After a detectable amount of analyte was accumulated, the dosing was stopped. The accumulated zones were mobilized to the analytical column, where they were analyzed by the ITP method with conductivity or photometric detection. The proper electrolyte systems for dosing, mobilizing, and analyzing in isoelectric focusing (IEF), moving boundary electrophoresis (MBE), and ITP modes were consequently developed and put into practice. The trapping selectivity can be regulated by the choice of pH and convenient complexing agents. A mixture of alkali earth metals were used as model analytes. Using a 3000 s dosing time, the proposed method improved the detection limit by 5-29 times in comparison to analysis by ITP with classical injection.