Sediment Standard Reference Materials
The National Institute of Standards and Technology (NIST, Gaithersburg, MD) issued a new series of Standard Reference Materials® (SRMs) targeting the ever-increasing list of potentially toxic substances in the aquatic environment that challenge environmental monitoring efforts and require new and improved analytical technologies for organic pollutants and trace metals. To support rapidly developing sectors of environmental analysis for the determination of polycyclic aromatic hydrocarbons (PAHs), polychlorinated biphenyl (PCB) congeners, and chlorinated pesticides, as well as for trace metal analysis, the NIST collection of SRMs was supplemented with the renewal material SRM 1941b Organics in Marine Sediment and the new materials SRM 2702 Inorganics in Marine Sediment and SRM 2703 Sediment for Solid Sampling (Small Sample) Analytical Techniques. SRMs 1941b, 2702, and 2703 were developed from the same source material collected from the Chesapeake Bay at the mouth of the Baltimore (MD) Harbor near the Francis Scott Key Bridge (39°12.3'N and 76°31.4'W) (see Figure 1). This location is very near the site where SRM 1941 and SRM 1941a, the precursors to SRM 1941b, were collected. The sediment was collected using a PVDF-coated modified Van Veen-type grab sampler. A total of approximately 3300 kg of wet sediment was collected from the site. The sediment was freeze-dried (56% solid mass fraction), sieved at 70 µm (100% passing), homogenized in a cone blender, radiation-sterilized at a 33–45 kGy (60Co) dose, and then packaged in screw-capped amber glass bottles, each containing approximately 50 g. The total amount had been divided into a lot for SRM 1941b and a lot for SRM 2702, with 20 kg set aside from the latter for SRM 2703. The processing of the collected material yielded a very uniform material with a median particle size of about 5 µm and nearly 100% smaller than 40 µm. Particle sizing analysis illustrates the uniformity of...
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