Estimation of magnesium and titanium using 3-aminopyridine-2-carbaxaldehyde thiosemicarbazone (triapine) by second-order derivative spectrophotometry

Abstract

The estimation of magnesium [Mg (II)] and titanium [Ti (IV)] using 3-aminopyridine-2-carboxaldehyde thiosemicarbazone (triapine) has been studied using the second-order derivative spectrophotometric approach. The reagent, triapine, produces a pale green color in a basic medium (at pH 8) when combined with Mg(II) and Ti(IV). The prominent peaks for Mg(II) and Ti(IV)-complexes in a UV–Visible spectrophotometer were found between 370 and 380 nm. Molar absorption and Sandell's sensitivity values of the coloured complexes viz., Mg(II) and Ti(IV)-triapine complexes were 9.269 × 106 L mol–1 cm–1, 7.96 × 103 L mol–1cm–1, and 0.0001 g/cm2, 0.125 g/cm2, respectively. Linearity is observed in the concentration range 0.121–1.318 µg/mL for Mg (II) and 0.012–0.122 µg/mL for Ti(IV). The concentration effect of Mg(II) and Ti(IV) ions on amplitude are also studied. Limit of detection (LOD) and Limit of quantification (LOQ) of Mg(II) and Ti(IV) are 0.00495 µg/mL, 0.015 µg/mL and 0.007 µg/mL, 0.0022 µg/mL respectively. The stability constant of the Mg(II) and Ti(IV)-triapine complex is determined as 4.260 × 104 and 3.236 × 105, respectively using Jobs method. The proposed method has been successfully applied for the determination of magnesium- titanium alloys in standard alloy steel, mineral, medicinal, and food samples. The results of the present study samples correlate well with those of the inductively coupled plasma atomic emission spectroscopy (ICP-AES), and food analysis in atomic absorption spectrophotometry (F-AAS).