Circular dichroism is an essential tool for the structural analysis of biological molecules such as proteins and nucleic acids. The typical path length of cells used for CD measurements is 1 mm, which makes it possible to measure sample volumes around 400 uL and concentrations as low as 0.1 mg/mL. However, there are many instances in which the sample size is even more limited.

The enhanced sensitivity of the J-1500 CD spectrometer enables CD spectra to be obtained with high accuracy and high signal-to-noise (S/N) ratio, even at microscale sizes, using a newly developed microcell with a small surface area.

In this application note, CD spectra of hemoglobin and DNA derived from bovine thymus are measured using a microsampling disc with the J-1500 CD spectrometer. The measurements were performed with a 3 uL sample volume to demonstrate the sensitivity of the J-1500 with small sample volumes in a microcell.