The particulate material used for the preparation of SRM 1650b was collected from the heat exchangers of a dilution tube facility following 200 engine hours of particulate accumulation. Several direct injection four-cycle diesel engines, operating under a variety of conditions were used to generate this particulatematerial. Therefore, while the sample is not intended to be representative of any particular diesel engine operating under any specific conditions, it should be representative of heavy-duty diesel engine particulate emissions. All of the chemical constituents for which certified and non-certified values are provided, are naturally present in the diesel particulate material. The certified values for the PAHs are based on the agreement of results obtained at NIST from two or more independent analytical methods. SRM 1650b is valid, with the measurement uncertainty specified, provided the SRM is handled and stored in accordance with instructions given under “Instructions forUse” in the certificate.
SRM 1650B_cert SRM 1650B _SDS