Ensure that the same amounts of potassium permanganate are added to standards and blanks, as all samples should receive the same amount of potassium permanganate until the purple color persists. Add 8mL of potassium persulfate and swirl sample bottles to mix. Samples should then be heated in a water bath for 2 minutes at 95 degrees Celsius. After 2 hours remove the samples from the water bath and allow to cool. When cool, add 6mL of hydroxylamine hydrochloride and swirl until the solution has decolorized.
Calibration curves are to be composed of a minimum of four standards as well as a method blank.
All calibration curves are to be printed out and saved in the mercury data binder. One method blank is to be run with every batch of mercury samples analyzed to determine if contamination or any memory effects are occurring. Matrix spikes and spike dupes are to be run every I0 samples.