Internal standardization as a strategy to overcome non-spectral interferences in the determination of As, Cd and Pb in mineral fertilizers by synchronous vertical dual view (SVDV) ICP OES
Elemental determination for fertilizer analysis by optical spectrometric techniques is often prone to non-spectral interferences due to the high content of easily ionizable elements (EIEs). Herein, we verify the use of internal standardization as a strategy for compensating for this matrix effect during As, Cd, and Pb determination in mineral fertilizers by SVDV ICP OES. Bismuth, Ir, Sc, and Y were chosen as internal standards (IS) and their ionic and atomic emission lines were carefully taken into account. The results indicated that the EIEs presence caused signal changes and internal standardization may be a suitable alternative to minimize this interference. By analyzing a certified reference material (CRM NIST 695) the best recoveries (from 94 to 106%) were achieved by applying internal standardization for all analytes. Concerning the elements evaluated as internal standards, Y (360.1 nm) and Sc (424.7 nm) were more suitable for As while Ir (215.8 nm) and Bi (190.2 nm and 195.4 nm) were suitable for Cd. For Pb, Ir (215.8 nm) was the most appropriate internal standard. The limits of detection using ISs were 0.70, 0.03 and 1.00 mg kg−1 for As, Cd and Pb, respectively. The application of internal standardization is an effective strategy to overcome matrix interferences in fertilizer analysis by SVDV ICP OES.