The data above shows plots of measured CD of dCSA solutions at 290 nm at aproximately 2 minutes per scan (results of 8 scans shown). Four solutions of dCSA were prepared by successive 5-fold dilutions of an approximately 20 mg/ml stock solution. CD scans were collected for each concentration and with two cuvettes with 10 mm (circles) and 1 mm (squares) pathlengths. Straight-line fits to the data prove photometric linearity over 4 orders of magnitude. No instrument setting whatsoever were changed between samples.