The National Institute of Standards and Technology (NIST), in collaboration with the National Institutes of Health (NIH), has developed a Standard Reference Material (SRM) to support technology development in metabolomics research. SRM 1950 Metabolites in Human Plasma is intended to have metabolite concentrations that are representative of those found in adult human plasma. The plasma used in the preparation of SRM 1950 was collected from both male and female donors, and donor ethnicity targets were selected based upon the ethnic makeup of the U.S. population. Metabolomics research is diverse in terms of both instrumentation and scientific goals. This SRM was designed to apply broadly to the field, not toward specific applications. Therefore, concentrations of approximately 100 analytes, including amino acids, fatty acids, trace elements, vitamins, hormones, selenoproteins, clinical markers, and perfluorinated compounds (PFCs), were determined. Value assignment measurements were performed by NIST and the Centers for Disease Control and Prevention (CDC). SRM 1950 is the first reference material developed specifically for metabolomics research.

AM.Determining lead sources in Mexico using the lead isotope ratio. Salud Publica Mex 2003;45 suppl 2:S183-S188. This paper is available too at: http://www.insp.mx/salud/index.html Abstract Objective. Lead poisoning can, in some cases, be traced to a specific route or source of exposure on the basis of the individual's blood lead isotope ratio. To assess the major source of lead exposure among women residing in Mexico City, we compared blood, ceramic, and gasoline lead isotope ratios. Material and Methods. The study population, randomly selected from participants of a large trial, (1/1996-12/1996) .9890 values for the three isotope ratios, respectively, suggesting that the lead exposure most likely resulted from the use of these ceramic. Measurements of lead isotope ratios from leaded gasoline in use at the time of blood sampling, differed from those in blood and ceramics. Conclusions. Determining lead isotope ratios can be an efficient tool to identify a major source of lead exposure and to support the implementation of public health prevention and control measures. This paper is available too at:

CDC has measured 25‐hydroxy‐vitamin D for NHANES using the DiaSorin RIA since NHANES III (1988‐94). Starting with NHANES 2007‐08, a tandem mass spectrometry method (LCMSMS) using a stable isotope internal standard will be used to measure 25‐hydroxy‐vitamin D2 (VID2) and 25‐hydroxy‐vitamin D3 (VID3). The method (Clin Chim Acta 2008;391:6) was recently revised to provide better chromatographic resolution, better sensitivity, and automation of sample preparation. Robotic volume delivery, robotic mixing and 96‐well plate format permit high throughput sample processing. The chromatographic run time is <10 min. Limits of detection are ≤1 ng/mL. Analytical coefficients of variation are <10% for VID3. Results for standard reference material (SRM 972) from the National Institute of Standards and Technology indicated acceptable accuracy for VID2 and VID3. Because of periodic fluctuations in long‐term quality control pools using RIA, samples from NHANES 2001‐06 are being tested using the LCMSMS method and conversion equations for LCMSMS‐RIA are being developed for each year. Samples (100/yr) were selected based on 2 criteria: 1) proportionally distributed RIA results (25 samples per unweighted quartile) and 2) an even distribution of RIA assay performance spread throughout the year. The goal of this change of methods is to improve VID assay precision. The simultaneous availability of SRM 972 will insure accuracy.