title: Trace element analysis of human urine collected after administration of Gd-based MRI contrast agents: characterizing spectral interferences using inorganic mass spectrometry.
abstract: Analysis of human urine is commonly used in biomonitoring studies to assess exposure to essential (e.g., Cu, Zn, Se) and non-essential (Pb, Cd, Pt) trace elements. These data are also used in epidemiological studies to evaluate potential associations between trace element exposure and various health outcomes within a population. Today most trace element analyses are typically performed using quadrupole-based inductively coupled plasma mass spectrometry (Q-ICP-MS). However, there is always the potential for spectral interferences with Q-ICP-MS instrumentation, especially when analyzing human specimens that may contain medications and other exogenous substances. Moreover, such xenobiotics may be unknown to the investigators. In a recent study focusing on environmental exposures and endometriosis: Endometriosis: Natural History, Diagnosis, and Outcomes (ENDO Study), urine specimens (n=619) were collected from participating women upon enrollment into the study or prior to surgery or pelvic magnetic resonance imaging (MRI), and analyzed for 21 trace elements by Q-ICP-MS. Here we report on some anomalous results observed for Se and Pt with elevated concentrations up to several orders of magnitude greater than what might be expected based on established reference intervals. Further investigations using Sector Field (SF-) ICP-MS instrumentation led to identification of doubly charged and polyatomic gadolinium (Gd) species traced to a Gd-based contrast agent that was administered to some subjects just prior to urine collection. Specifically, interferences from Gd2+and several minor polyatomics were identified as interferences on all of the major isotopes of Se including74Se,76Se,77Se,78Se,80Se, and82Se. While trace amounts of Pt were present in the urine, a number of Gd-containing polyatomic species were also evident as major interferences on all isotopes of Pt (190Pt,192Pt,194Pt,195Pt,196Pt, and198Pt), including Gd-chlorides, Gd-argides, and Gd-oxides. These observations underscore the importance of considering potential isobaric interferences when interpreting unusual trace element results for clinical specimens.
authors.affiliation: Laboratory of Inorganic and Nuclear Chemistry, Wadsworth Center, New York State Department of Health, P.O. Box 509, Albany, NY, 12201-0509, USA.; Department of Environmental Health Sciences, School of Public Health, The University at Albany, P.O. Box 509, Albany, NY, 12201-0509, USA.
authors.forename: Amy J
authors.initials: AJ
authors.lastname: Steuerwald
authors.affiliation: Laboratory of Inorganic and Nuclear Chemistry, Wadsworth Center, New York State Department of Health, P.O. Box 509, Albany, NY, 12201-0509, USA.; Department of Environmental Health Sciences, School of Public Health, The University at Albany, P.O. Box 509, Albany, NY, 12201-0509, USA.
authors.forename: Patrick J
authors.initials: PJ
authors.lastname: Parsons
authors.affiliation: Laboratory of Inorganic and Nuclear Chemistry, Wadsworth Center, New York State Department of Health, P.O. Box 509, Albany, NY, 12201-0509, USA.; Department of Environmental Health Sciences, School of Public Health, The University at Albany, P.O. Box 509, Albany, NY, 12201-0509, USA.
authors.forename: John G
authors.initials: JG
authors.lastname: Arnason
authors.affiliation: Division of Epidemiology, Statistics and Prevention Research, Eunice Kennedy Shriver National Institute of Child Health and Human Development, 6100 Executive Blvd Room 7B03, MSC 7510, Bethesda, MD, 20892-7510, USA.
authors.forename: Zhen
authors.initials: Z
authors.lastname: Chen
authors.affiliation: Division of Reproductive Endocrinology and Infertility, Department of Obstetrics and Gynecology, The University of Utah School of Medicine, 30 N 1900 E, Rm 2B200, Salt Lake City, UT, 84132, USA; Department of Obstetrics and Gynecology, The University of Utah Nano Institute of Utah, 30 N 1900 E, Rm 2B200, Salt Lake City, UT, 84132, USA.
authors.forename: C Matthew
authors.initials: CM
authors.lastname: Peterson
authors.affiliation: Division of Epidemiology, Statistics and Prevention Research, Eunice Kennedy Shriver National Institute of Child Health and Human Development, 6100 Executive Blvd Room 7B03, MSC 7510, Bethesda, MD, 20892-7510, USA.
authors.forename: Germaine M Buck
authors.initials: GM
authors.lastname: Louis