Determination of sulfur and phosphorus in solutions by inductively coupled plasma atomic emission spectrometry utilizing direct graphite cup insertion technique.

Direct introduction of a graphite cup into an inductively coupled plasma has been investigated as a method for the determination of sulfur and phosphorus in solutions. The detection limit obtained by measuring the S I 190.027 nm spectral line intensity in an air atmosphere is 1.0 μg/ml. Relative standard deviation at a concentration 100 times the detection limit is about 3%. Thus the results demonstrate the applicability of the present method to practical analysis. A detection limit of 5 ng/ml and a relative standard deviation of 2% are obtained for phosphorus (P I 213.618 and P I 214.911 nm) by optimizing the measurement conditions. The detection limit is close to 15 times that of the conventional method using a nabulizer, and therefore the method is usefull especially for the determination of trace amounts of phosphorus in solutions.