Phytochelatins are known to play an essential role in xenobiotic detoxification in some plants. Until now, their synthesis in plants exposed to platinum group elements (PGEs), especially Pd and Rh, has not been directly proven. The influence of PGEs on the natural environment, especially on living organisms, is particularly important in view of increasing emissions of these elements from automotive catalytic converters. This paper describes studies related to the identification of the presence of phytochelatins in tissues of white mustard (Sinapis alba L.) exposed to Pt, Rh, and Pd salts. Phytochelatins were identified by high-performance liquid chromatography with two types of detection: fluorescence (FLD) for thiols after derivatization, and electrospray ionization mass spectrometry (ESI MS) for thiols in fresh extracts. Our study confirmed the synthesis of phytochelatins in some plant organs under the influence of PGEs, and illustrated the differences in plant response to stress caused by Pt, Rh, or Pd.