As the first step toward understanding the involvement of endogenous brassinosteroids (BRs) in cytodifferentiation, we analyzed biosynthetic activities of BRs in zinnia (Zinnia elegans L. cv Canary Bird) cells differentiating into tracheary elements. The results of feeding experiments suggested that both the early and late C6-oxidation pathways occur during tracheary element differentiation. Ga...

Water is a necessity for life. Currently, because of different contaminations in tap water, most people prefer using bottled mineral waters. Pesticides (e.g., organophophorous, carbamates, etc.) are among the most dangerous chemicals that may be found in drinking waters, which can cause long- and short-term complications. Because all people consume at least 2 L of water per day, water-quality m...

Determination of the more common light elements such as nitrogen and chlorine at trace levels is difficult because of their high abundance on sample surfaces, in materials used to build analysis instruments, and in the residual gas of the instrument vacuum. We present here a new approach to analysis of these elements: accelerator mass spectrometry (AMS) combined with neutron activation. The pro...

Maximum admissible concentration level (MACL) of barium in natural mineral waters, natural spring waters and potable waters was set at the level of 1 mg/l, while MACL of this element in natural curative waters intended for drinking therapies and inhalations were set at the levels of 1.0 mg/l and 10.0 mg/l, respectively. Those requirements were related to therapies which are applied longer than ...

Surface water reservoirs and aquifers are exposed to contamination by thousands of micropollutants from industrial, pharmaceutical, agricultural and natural origins. Most developed and developing countries implement a water-quality regulation programme to prevent contamination by such chemicals at illegal concentrations. Traditionally, analytical methods based on gas chromatography-mass spectro...

physical and chemical properties of  crude oil, including viscosity and api gravity, are commonly inherited  from the  early organic matter, environmental conditions in which they were deposited and depth of burial of the source beds. api gravity increases in deeper burial due to higher thermal maturation of organic matter in the source rocks and consequently, generation of lighter saturated hy...

BACKGROUND A method of the classification of natural mineral and spring waters and maximum admissible concentration (MAC) levels of metals present in such types of waters are regulated by Commission Directive 2003/40/EC, Directive 2009/54/EC of the European Parliament and of the Council and Ordinance of Minister of Health of 30 March 2011 on the natural mineral waters, spring waters and potable...

Derivatization reactions are meant to transform an analyte for detectability in Gas Chromatography (GC) or other instrumental analytical methods. Derivatization in GC analysis can be defined as a procedural technique that primarily modifies an analyte’s functionality in order to enable chromatographic separations. A modified analyte in this case will be the product, which is known as the deriva...

Comprehensive two-dimensional gas chromatography can be viewed as a traditional gas chromatography with a sophisticated "elution-resolved" flame ionization detector (GC/FID) or a detector with separation capability. The concept of multidimensional chromatography can be extended to other detectors that also have separation capability, such as ultraviolet, infrared, and mass spectrometer. Mass sp...