Milk and serum standard reference materials for monitoring organic contaminants in human samples

Abstract

Four new Standard Reference Materials (SRMs) have been developed to assist in the quality assurance of chemical contaminant measurements required for human biomonitoring studies, SRM 1953 Organic Contaminants in Non-Fortified Human Milk, SRM 1954 Organic Contaminants in Fortified Human Milk, SRM 1957 Organic Contaminants in Non-Fortified Human Serum, and SRM 1958 Organic Contaminants in Fortified Human Serum. These materials were developed as part of a collaboration between the National Institute of Standards and Technology (NIST) and the Centers for Disease Control and Prevention (CDC) with both agencies contributing data used in the certification of mass fraction values for a wide range of organic contaminants including polychlorinated biphenyl (PCB) congeners, chlorinated pesticides, polybrominated diphenyl ether (PBDE) congeners, and polychlorinated dibenzo-p-dioxin (PCDD) and dibenzofuran (PCDF) congeners. The certified mass fractions of the organic contaminants in unfortified samples, SRM 1953 and SRM 1957, ranged from 12 ng/kg to 2200 ng/kg with the exception of 4,4'-DDE in SRM 1953 at 7400 ng/kg with expanded uncertainties generally <14 %. This agreement suggests that there were no significant biases existing among the multiple methods used for analysis.

Polybrominated Diphenyl Ethers, Polychlorinated Biphenyls, and Persistent Pesticides in Serum from the National Health and Nutrition Examination Survey: 2003–2008

“…The median amount in pg/g serum detectable in blank samples analyzed in parallel with unknown samples as well as the LOD for each analyte measured is given in SI Table S2. The CV of quality control samples made from the standard reference material (SRM) 1958 9 was below 10%.…”

Development of urine standard reference materials for metabolites of organic chemicals including polycyclic aromatic hydrocarbons, phthalates, phenols, parabens, and volatile organic compounds

“…As part of ongoing collaborations with the Centers for Disease Control and Prevention (CDC) [6], the National Institute of Standards and Technology (NIST) has developed two new Standard Reference Materials (SRMs) for organic contaminants in urine, SRM 3672 Organic Contaminants in Smokers’ Urine (Frozen) and SRM 3673 Organic Contaminants in Non-Smokers’ Urine (Frozen). These two materials have been characterized for hydroxylated PAHs (OH-PAHs), phthalate metabolites, phenols, parabens, VOC metabolites, creatinine, and the free forms of caffeine, theobromine, ibuprofen, nicotine, cotinine, and 3-hydroxycotinine.…”

“…Exposure assessment relying on the urinary metabolites characterized in these materials can be used to identify exposure sources, follow exposure trends, and study potential health effects associated with exposures. Similar to the two serum and two human milk SRMs previously characterized for organic environmental contaminants [6, 15], these urine materials will be useful in validating methods used for exposure assessment and developing methods for future chemicals of concern.…”

Performance and storage integrity of dried blood spots for PCB, BFR and pesticide measurements

“…[43] In brief, DBS punches (15 mm dia) containing the DBS were placed in a 15 mL glass tube (Fisher Scientific, Pittsburgh, PA), and treated with hydrochloric acid (1 ml, 6 M) and then 1:1 ethanol/isopropanol mixture (6 mL). The sample was extracted twice using 1:1 hexane/methyl-t-butyl ether (6 mL, MTBE).…”

“…[43] (2) Concentration measured in 1 ml samples of reconstituted SRM. (3) Concentration measured in 50 μl blood spot samples using reconstituted SRM. …”