The suitability of the dry ashing procedure for determination of arsenic in marine samples.

The dry ashing procedure with Mg/(NO3)2/Mgo ashing aid, followed by arsenic determination by colorimetry, has been compared to an X-ray fluorescence method for determination of arsenic in marine samples. Good agreement between these techniques indicated the suitability of the dry ashing, colorimetric procedure for determination of "fish-arsenic". A wet digestion procedure using HNO3-H2SO4-HC104 was also shown to be suitable.