Apparatus
a. See Section 5220C.2. Ensure that reaction vessels are of optical quality. Other types of
absorption cells with varying path lengths may be used. Use the extinction coefficients of the
ions of interest for this approach.
b. Spectrophotometer, for use at 600 nm and/or 420 nm with access opening adapter for
ampule or 16-, 20-, or 25-mm tubes. Verify that the instrument operates in the region of 420 nm
and 600 nm. Values slightly different from these may be found, depending on the spectral
bandpass of the instrument.
3.