Selective spectrophotometric determination of palladium(II) with 2(5-nitro-2-pyridylazo)-5-(N-propyl-N-3-sulfopropylamino)phenol(5-NO(2).PAPS) and tartaric acid with 5-NO(2).PAPS-niobium(V) complex.

Spectrophotometric determinations of palladium(II) and tartaric acid were respectively investigated by using the color reactions between 2(5-nitro-2-pyridylazo)-5-(N-propyl-N-3-sulfopropylamino)phenol(5-NO(2).PAPS) and palladium(II) in strong acidic media, and between 5-NO(2).PAPS, niobium(V) tartaric acid in weak acidic media. The calibration graphs were linear in the range of 0-25 microg/10 ml palladium(II), with an apparent molecular coefficient (epsilon) of 6.2 x 10(4) l mol(-1) cm(-1) at 612 nm, and 0-23 microg/10 ml tartaric acid with epsilon=1.08 x 10(6) l mol(-1) cm(-1) at 612 nm, respectively. The proposed methods were selective and sensitive in comparison with other chelating pyridylazo dyes-palladium(II) or metavanadic acid-tartaric acid method, and the effect of foreign ions such as copper(II) was negligible for the assay of palladium(II) with 5-NO(2).PAPS.