The γ ray from

241

Am source were used to excite silver target for producing characteristic K radiation. The collimated beam of K radiation is passed through the sample cell. The intensity of the unabsorbed radiation is measured with a NaI(T1) crystal. Near the absorption edges of molybdenum

its mass absorption coefficient is bigger

so the interference of some impurities in the solution is eliminated. The method gives very good accuracy (better than 1%). Twenty samples can be analyzed in about an hour.