The DNA IQ™ System is a DNA isolation system designed specifically for forensic laboratories to extract DNA from a variety of sample types, both liquid and solid support. Often these forensic samples contain very low or limiting amounts of DNA. For forensic laboratories, it is important to accurately quantitate the amount of DNA present in these samples as downstream applications such as STR amplification require specific amounts of template for proper analysis and identification of the sample source. DNA IQ™ chemistries are available to purify forensic samples manually, on the Maxwell® 16 Instrument and on larger robotic systems.
The most commonly used technique for measuring nucleic acid concentration is the determination of absorbance at 260nm (A260); however, there are major disadvantages of the absorbance method including: the large relative contribution of nucleotides and single-stranded nucleic acids to the signal, interference caused by contaminants commonly found in nucleic acid preparations, the inability to distinguish between DNA and RNA, and the relative insensitivity of the assay (traditional spectrophotometric assays cannot determine nucleic acid concentrations below 2μg/ml). The use of sensitive, fluorescent nucleic acid stains alleviates many of these problems. Thus, for forensic laboratories these systems represent an accurate, sensitive, fast and inexpensive means of DNA quantitation.
This Application Note describes the protocol for quantitating DNA samples purified using the DNA IQ™ chemistries on the Quantus™ Fluorometer.