Determination of neodymium with 1-(2-pyridylazo)-2-naphthol by high-order derivative spectrophotometry. Application to the determination of neodymium in glasses

Abstract

A method is described for the spectrophotometric determination of neodymium by measuring the peak to valley signal of the fourth-derivative of the absorption of the Nd-PAN-Triton X-100 system. The chemical and instrumental variables (wavelength range, Δλ and order of the derivative) were optimised by the modified simplex method. Under the optimum experimental conditions the calibration line fits the equation d⁴A/dλ⁴= 2.48 × 10⁵[Nd]– 0.002 (r= 0.9998) and has a detection limit of 11 p.p.b. The method was applied to the determination of neodymium in glasses.