Identification and Quantification of Gluconic, Metasaccharinic, Glyceric, Formic, and Acetic Acids as Novel Glucose...

Peritoneal dialysis (PD) fluids often contain glucose as the osmotic agent. Heat sterilization ensures their microbiological safety, but the heat impact degrades glucose. The altered composition and reduced biocompatibility of the fluids limit the long-term use of PD. A key indicator of glucose degradation is a decrease in pH poststerilization suggesting that carboxylic glucose degradation products (carboxyl GDPs) were formed. The present study employed a precursor ion mass spectrometry screening using 3-nitrophenylhydrazine derivatization to investigate the presumed carboxylic products. Based on enhanced product ion spectra, structures were suggested, which were confirmed by comparing the chromatographic and mass spectrometric properties of the unknown signals to reference compounds. Thus, five carboxylic acids were identified in commercial PD fluids, namely, gluconic, metasaccharinic, glyceric, formic, and acetic acids. The new carboxyl GDPs were quantified in the PD fluids showing 47.8-62.6 μM gluconic, 125.8-180.7 μM metasaccharinic, 3.2-6.6 μM glyceric, 28.4-37.3 μM acetic, and 60.1-92.3 μM formic acids. The total amount of the newly identified acids ranging from 287.3 to 373.3 μM explains almost completely the poststerilization pH decrease of the PD fluids. The present findings show that heat sterilization induces the formation of carboxylic glucose degradation products in PD fluids.