Abstract
A highly sensitive spectrophotometric determination (Δε=εblank-εsample=3.0 ×105l mol-1 cm-1) for nitrite ion using 5, 10, 15, 20-tetrakis(4-aminophenyl)porphine (TAPP) was developed. This method is based only on the formation of the diazonium salt. Recommended procedure: A 2.0 ml aliquot of 10-5 mol/l TAPP solution and 2.5 ml aliquot of 1.0 mol/l HCl were mixed, the sample solution containing nitrite ion added and the volume then made up to 25 ml with water. After 30 min at 30°C, the absorbance at 434 nm was measured. The determination range was 1.0 × 10-84.0× 10-7 mol/l (0.4618 ppb) and the detection limit (S/N= 3) was 4.0 × 10-9 mol/l (0.18 ppb). The relative standard deviation of the median was 1.03% (10 determinations). This simple method will be applicable to various assays such as environmental analysis and clinical diagnosis.
