Abstract:

In a pH 5.0~7.6 Britton-Robinson(BR) buffer medium, Furosemide(FUR) reacted with Pd(Ⅱ) to form a 1∶1 anionic chelate, which further reacted with some basic triphenylmethane dyes(BTPMD) such as ethyl violet(EV), crystal violet(CV), methyl violet(MV), methyl green(MeG), and brilliant green(BG) to form 1∶1 ionic complexes. The absorption spectra of the dyes were changed and fading peak are 595 nm for EV and CV systems, 580 nm for MV system, 615 nm for BG system and 630 nm for MeG system. There was an linearity between the concentrations of FUR and ΔA of the solutions at the maximum fading peaks. The quantitative determination ranges of five the triphenylmethane dyes were 2.0×10-7~4.0×10-6 g/mL for EV system, 3.0×10-7~8.0×10-6 g/mL for CV system, 4.0×10-7~4.0×10-6 g/mL for MV system, 4.0×10-7~7.0×10-6 g/mL for BG system and 1.2×10-6~8.0×10-6 g/mL for MeG system. Depending on the different dyes systems, the molar absorption coefficiencies(ε) of different systems were between 0.57×104~3.40×104 L/(mol·cm) and the detection limit(3ε) was 6.0×10-8 g/mL. A new spectrophotometry for the determination of FUR was set up based on above results. In the five systems, the optimal conditions of the reactions and the effects of external substances were investigated, the method has been applied to the determination of FUR in urine samples with satisfactory results. The mean recoveries ranged from 96.0% to 106.8%.

Key words: palladium(II), furosemide, triphenylmethane dyes, spectrophotometry