Determination of the Impurity Composition of Boric Acid by Inductively Coupled Plasma Optical Emission Spectrometry

Procedures for the determination of 53 impurities, including rare earth elements, in boric acid by inductively coupled plasma optical emission spectrometry (ICP–OES) have been developed. To optimize analysis conditions, the variation of impurity element signals was studied at boron concentrations ranging from 0 to 5000 mg/L and plasma powers of 1000, 1300, and 1600 W under axial observation. Most impurity elements exhibited the maximum analytical signals at the highest plasma power and at the highest boron concentration in the test solution. Taking into account the significant effect of the matrix on impurity element signals starting from approximately 500 mg/L of the matrix element, calibration curves were constructed using the spike method. The accuracy of the analysis was confirmed by spiking with the analyte elements with recoveries of 85–115%. The limits of detection calculated by the 2s test ranged from n × 10–7 to n × 10–4 wt %.