Hello,

I've encountered a significant issue with Qubit 2.0 readings on DNA extracts of Arctic plant roots. The samples have all been run previously, and when double-checking them, the readings are significantly different from the previous run (10 to ~300 ng/ml differences). In an effort to get correct quantification, a fresh box of DNA HS reagents was used, and a set of samples was remade (198 ul of working solution with 2 ul of DNA extract). Almost all samples showed DNA levels above detection limits, when previously they had been in range. Samples that were in range were ran several more times and left to equalize to room temperature between readings, showed increasing concentrations over time.

For example, one sample was run several times using the same standards, and the sample was kept closed the entire time. The readings for each subsequent run were around 194 ng/ml, 230 ng/ml, 370 ng/ml, 430 ng/ml, and 477 ng/ml.

I am entirely unsure as to what may be occurring and resulting in drastically different quantification between readings of the same sample. To check the Qubit, a lab technition ran several previous samples she had created, and all were within 5 ng/ml of their original recorded value. Standards from the new DNA HS assay kit were ran against standards from the previous kit, and did not show any appreciable differences.

Is there possible contamination in my DNA samples that could result in these inconsitant readings? Or does anyone have any suggestions and how to troubleshoot this particular issue?