The surface characterization of CdTe QDs synthesized by a novel procedure using glutathione (GSH), low temperatures (60-90 degrees C) and K2TeO3 as the -Te precursor is reported. Fluorescence of the produced QDs is stable in the pH range 6-13 and QDs inside eukaryotic cells are highly fluorescent. The surface composition of GSH-CdTe QDs with different spectroscopic properties and particle size distributions was determined by XPS. The XPS analysis indicated that the QDs are essentially CdTe, although all nanoparticles contain 12-24% of CdO (and in one case also TeO2). GSH decomposes with reaction time releasing small amounts of S-2 ions that react with Cd(Te) to yield Cd(Te)S in a smaller amount than that of CdTe. Finally, the use of QDs in fluorescence mediated immunodetection of bacterial pathogens has been evaluated. (C) 2013 Elsevier B.V. All rights reserved.