Application of selective extraction and reverse phase chromatography with three detectors - PAD, FLD and ESI MS for characterization of platinum metabolites and identification of phytochelatins in Sinapis alba L. tissues

Several extraction procedures, with reagents having the potential to select different groups of compounds (water-soluble, polypeptide and polysaccharide complexes) were used to characterize platinum species in hydroponically cultivated plant white mustard (Sinapis alba L.). It was found, that 10% (roots) to 50% (leaves) of platinum species present in plants are soluble in water. Platinum is also bound to the hydrophobic proteins and polysaccharides in the cell walls. In plants exposed to the contaminant during the whole time of their cultivation, platinum was stronger bond to the matrix in comparison with plants exposed to platinum salt for the last week of their growth. To control the synthesis of phytochelatins in plants three different procedures were applied. Triple-step pulsed amperometry was used to detect selectively sulfur-containing compounds after their chromatographic separation. In the extract of mustard leaves together with other investigated thiol-compounds, phytochelatin containing two α-glutamylcysteine dipetide groups (PC2) was found. The presence of PC2 in plant extract was confirmed by HPLC FLD and ESI MS analysis after thiols derivatisation.