Length-dependent DNA degradation kinetic model: Decay compensation in DNA tracer concentration measurements

DNA is often used as a tracer in both environmental fluid flow characterization and in material tracking to avoid counterfeiting and ensure transparency in product value chains. The main drawback of DNA as a tracer is its limited stability, making quantitative analysis difficult. Here, we study length-dependent DNA decay at elevated temperatures and under sunlight by quantitative PCR and show that the stability of randomly generated DNA sequences is inversely proportional to the sequence length. By quantifying the remaining DNA length distribution, we present a method to determine the extent of decay and to account for it. We propose a correction factor based on the ratio of measured concentrations of two different length sequences. Multiplying the measured DNA concentration by this length-dependent correction factor enables precise DNA tracer quantification, even if DNA molecules have undergone more than 100-fold degradation. © 2018 American Institute of Chemical Engineers AIChE J, 65: 40–48, 2019