The biotechnology industry relies primarily on absorbance and fluorescence methodologies to assess DNA mass. However, these measurements can be seriously compromised by impurities in the DNA preparations or state of the DNA itself. These techniques are also not traceable to the SI because the calibrations cannot currently be performed using calibration standards whose values are traceable to the SI. Such techniques cannot achieve the high accuracy and precision required to produce SRMs for nucleic acid materials.
At NIST in collaboration with The George Washington University (GWU), a methodology that can be used to provide accurate measurements of DNA and nucleic acid mass that are traceable to the SI is being developed with the long-term goal of providing an SRM for DNA mass. Currently, the ICP-OES approach developed at NIST, referred to as high-performance ICP-OES (HP-ICP-OES) incorporating a ratio-based technique with drift correction, has been utilized for the measurement of phosphorus content of acid-digested nucleotides and DNA. The HP-ICP-OES measurement of phosphorus provides a highly accurate quantification of mass for both nucleotide monophosphate and DNA with relative uncertainties less than 0.1 % (95 % confidence level). However, the current approach requires a significant sample size (10 mL of solution containing a DNA concentration of 50 μg/mL), restricting its usefulness for the quantification of DNA. A demountable, direct-injection high-efficiency nebulizer (d-DIHEN), developed by GWU, is incorporated to limit sample consumption via the introduction of samples at low sample uptake rates.