Recertification of the NIST Standard Reference Material® 2372, human DNA quantitation standard

Abstract During the process of recertification of SRM 2372 (human DNA quantitation standard) a significant (14–26%) increase in decadic attenuance (absorbance) was detected. SRM 2372 consists of extracted human genomic DNA solutions assumed to be in the double stranded state. After further investigation by UV spectroscopy revealed that the materials were slowly dissociating to a single-stranded state. This did not affect the use of the materials in qPCR assays, but was in fact out of the limit of the NIST certified absorbance value. A method was developed to fully convert the materials to the single stranded state and absorbance was the re-measured. The recertified absorbance values were found to be within the error of common qPCR assays and allowed the materials to be returned to market.