Trace determination of gadolinium in biomedical samples by diode laser-based multi-step resonance ionization mass spectrometry.
The application of high-resolution multi-step resonance ionization mass spectrometry (RIMS) to the trace determination of the rare earth element gadolinium is described. Utilizing three-step resonant excitation into an autoionizing level, both isobaric and isotopic selectivity of >10(7) were attained. An overall detection efficiency of approximately 10(-7) and an isotope specific detection limit of 1.5 x 10(9) atoms have been demonstrated. When targeting the major isotope (158)Gd, this corresponds to a total Gd detection limit of 1.6 pg. Additionally, linear response has been demonstrated over a dynamic range of six orders of magnitude. The method has been used to determine the Gd content in various normal and tumor tissue samples, taken from a laboratory mouse shortly after injection of gadolinium diethylenetriaminepentaacetic acid dimeglumine (Gd-DTPA), which is used as a contrast agent for magnetic resonance imaging (MRI). The RIMS results show Gd concentrations that vary by more than two orders of magnitude (0.07-11.5 microg mL(-1)) depending on the tissue type. This variability is similar to that observed in MRI scans that depict Gd-DTPA content in the mouse prior to dissection, and illustrates the potential for quantitative trace analysis in microsamples of biomedical materials.
Blaum
K
K
Institüt für Physik, Johannes Gutenberg-Universität Mainz, Germany. klaus.blaum@cern.ch
Geppert
C
C
Schreiber
W G
WG
Hengstler
J G
JG
Müller
P
P
Nörtershäuser
W
W
Wendt
K
K
Bushaw
B A
BA
D000818:Animals; D003287:Contrast Media; D005682:Gadolinium / Q000032:analysis*; D007554:Isotopes / Q000032:analysis; D007834:Lasers; D008279:Magnetic Resonance Imaging; D013058:Mass Spectrometry / Q000295:instrumentation* / Q000379:methods*; D051379:Mice; D008819:Mice, Nude; D009369:Neoplasms / Q000737:chemistry / Q000473:pathology; D009928:Organ Specificity; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity
D003287:Contrast Media; D007554:Isotopes; D005682:Gadolinium