Quantification of nucleic acid

Ultraviolet-visible (UV-VIS) spectrophotometers are used in quantitative and qualitative analysis of substances in many fields. Purity confirmation and quantitation of nucleic acids, proteins, and other substances are also performed in the life sciences, but measurement at the trace level is demanded, as only small samples are available in many cases. This article introduces an example of quantitation of nucleic acid with a Shimadzu UV-1900 UV-VIS spectrophotometer with two type of cells which enable measurement of sample quantities of several μL. The Biomethod Mode of the UV-1900 is also introduced briefly.

The BioSpec-nano has 2 optical pathlengths (0.2 mm, 0.7 mm), allowing quantitation of nucleic acid with sample volumes of 1 μL and 2 μL, respectively. In addition, if the optional cell (sample volume: 2 mL) having a 5 mm pathlength is used, measurement can be conducted using the cell (cuvette). Here we conducted measurement of dsDNA at various concentrations at each optical pathlength, and we report the results on the linearity of photometric values (OD) obtained from nucleic acid quantitation, as well as the measurement repeatability as CV (%), and accuracy of the photometric values (OD). In addition, we also investigated the effect of the automatic wiping performance conducted during nucleic acid quantitation.