Comparison of effectiveness of different ashing auxiliaries for determination of phosphorus in natural waters, aquatic organisms and sediments by ignition method.

An improved method for the determination of phosphorus in natural waters, aquatic organisms and sediments by ignition method is proposed. The recoveries of phosphorus (P) from selected inorganic and organic P-containing compound standards after ignition with different auxiliaries, such as MgSO(4), Mg(NO(3))(2), MgCl(2), Mg(Ac)(2) and CaCl(2), were compared. We found that the phosphorus from most compound standards could not be completely recovered when these compounds were ignited (450-500 degrees C) with the MgSO(4) as auxiliary and the baked residue was extracted with 0.