Spectrophotometric determination of microgram amounts of calcium in waters and foods using diphenylglyoxal bis(2-hydroxybenzoyl hydrazone)

Abstract

The synthesis, characteristics and analytical applications of diphenylglyoxal bis(2-hydroxybenzoyl hydrazone) are described. This compound reacts with calcium(II) at pH 12 to produce a yellow complex (λ_max. = 432 nm, ε= 1.76 × 10⁴ l mol^–1 cm^–1); another complex (1:1) can be detectd at pH 7.80. Dipyridylglyoxal bis(2-hydroxybenzoyl hydrozone). A sesnitive and selective spectrophotomeric method is proposed for the determination of clcium using diphenylglyoxal bis(2-hydroxybenzoyl hydrazone). Interferences have been investigated and when masking agents are added common cations do not interfere. The yellow calcium(II) complex has been used for the determination of clcium in waters and foods. The esults are compared with those obtained using glyoxal bis(2-hydroxyanil).