Some modified
ribonucleosides in
biological fluids have been evaluated as
cancer-related metabolites. Detection of endogenous modified
ribonucleosides in
biological fluids may serve as a noninvasive
cancers diagnostic method. However, determination of modified
ribonucleosides is still challenging because of their low abundance and serious matrix interferences in
biological fluids. Here, we developed a novel strategy for comprehensive profiling of
ribose conjugates from
biological fluids using
metal oxide-based dispersive solid-phase extraction (
DSPE) followed with in vitro stable
isotope labeling and double neutral loss scan-mass spectrometry analysis (
DSPE-SIL-LC-DNLS-MS).
Cerium dioxide (CeO2) was used to selectively recognize and capture
ribose conjugates from complex
biological samples under basic environment. The enriched
ribose conjugates were subsequently labeled with a pair of
isotope labeling
reagents (
acetone and
acetone-d6). The glucosidic bond of
acetone labeled
ribose conjugates is readily ruptured, and the generated
ribose that carries an
isotope tag can be lost as a neutral fragment under collision induced dissociation (CID). Since the light (
acetone) and heavy (acetone-d6) labeled compounds have the same chemical structures and can generate different neutral loss fragments (NL 172 and 178 Da), it is therefore highly convenient to profile
ribose conjugates by double neutral loss scan mode in mass spectrometry analysis. In this respect, the light and heavy labeled compounds were ionized at the same condition but recorded separately on MS spectra, which can significantly improve the detection specificity and facilitate the identification of
ribose conjugates. Using the developed
DSPE-SIL-LC-DNLS-MS strategy, we profiled the
ribose conjugates in human urine, and 49
ribose conjugates were readily identified, among which 7
ribose conjugates exhibited significant contents change between healthy controls and
lymphoma patients. The
DSPE-SIL-LC-DNLS-MS strategy combines the selective enrichment, stable
isotope labeling, and double neutral loss scan - MS analysis, which therefore can efficiently minimize false positive results, facilitate the relative quantification, and notably increase the numbers of identified
ribose conjugates in
biological fluids samples. Taken together, this study established a promising strategy for the effective profiling of urinary modified
ribonucleosides, and simultaneous evaluation of the contents change of multiple modified
ribonucleosides should provide more accurate and conclusive results for the use of urinary modified
ribonucleosides as indicators of
cancers.