Abstract
The atomic absorption of calcium with air-acetylene flame is interfered with by the presence of phosphate. It was found that the interference was reduced by adding Triton X-100 into the calcium solution. The absorption of calcium containing phosphate increased rapidly as the concentration of Triton X-100 increased, and reached a maximum value. Then it decreased to a minimum value and again gradually increased to a constant absorption value as the concentration of Triton X-100 increased. The maximum absorption of calcium appeared in the presence of low concentrations of Triton X-100; this was attributed to the decrease of surface tension, the decrease of the size of sprayed droplets, and the increase of the sample uptake rate. The enhancement effect of Triton X-100 in its higher concentrations was attributed to the reducing action of ultra-fine carbon particles produced in the flame. Several organic substances of large molecular weight which dissolve in water, such as tetramethylammonium chloride, tetraethylammonium chloride, etrapropylammonium chloride, tetrabutylammonium chloride, tiron and tannic acid, were also effective in enhancing the calcium absorption. The analysis of calcium containing phosphate could be carried out in the presence of Triton X-100 in its higher concentrations.
