Determination of ultra-trace amount Chromium in water samples with 2-hydroxynaphthaldehydebenzoylhydrazone (HNPBH) by the potassium chlorate ion in sulfuric acid with kinetic spectrophotometric method

A new kinetic spectrophotometic method for the determination of trace amount Chromium(III) in Tea real samples has been described based on it s the catalytic effect on the oxidations of 2-hydroxynaphthaldehydebenzoylhydrazone (HNPBH), by potassium chlorate in sulfuric acid. The reaction is followed spectrophotometrically by measuring the decrease in the absorbance at 469 nm. Under the optimum conditions of 0.2 molL-1 sulfuric acid, 1.0 × 10-4 molL-1, 2-hydroxynaphthaldehydebenzoylhydrazone (HNPBH), 0.01 mol L-1 potassium chlorate at 35oC, calibration graph in the rang of 0.001-0.06 mg L-1 Chromium(III).Concentration was obtained with detection limit of 0.2303 g mL-1 by the fixed-time method of 5.5 min. The relative standard deviation for 0.05 mg L-1Chromium(III) is %90. No serious interference was identified. The applicability of the method was demonstrated by the determination of the Chromium(III) in Water samples.