A simple method for estimating calcium in DNP and DNA by flame photometry is described. Measurements cannot be made directly on solutions of DNP and DNA in water because of interference effects but on extraction in 0.05 N HCl these are overcome. The criteria used for assessing absence of interference are: (1) similarity of emission spectra to that of standard calcium, (2) independence of emission, relative to the standard, on flame temperature, and (3) recovery of added standard calcium over a range of concentrations both of standard and of DNP or DNA. Results obtained by this method and by incineration of the DNP and DNA are compared. Calcium levels range from 0.67 to 0.97 × 10-5 M in different preparations of DNP, at 0.01% DNA. The level in a commercial sample of DNA at 0.01% is about 1 × 10-5 M. © 1970.
|Number of pages||10|
|Publication status||Published - Jan 1970|