Study on solid phase extraction and spectrophotometric determination of cadmium with 2-(2-quinolinylazo)-4-methyl-1,3-dihydroxybenzene

The color reaction of 2-(2-quinolinylazo)-4-methyl-1,3-dihydroxidebenzene (QAMDHB) with cadmium was studied. In the presence of pH=8.0 buffer solution and TritonX-100 medium, QAMDHB can react with cadmium (II) to form a stable 2:1 complex (QAMDHB: Cd(II)). The molar absorptivity is 1.01×10 5 L.mol -1.cm -1 at 560 nm. Beer's law is obeyed in range of 0-1.0 μg/ml. The cadmium ion in samples can be enriched and separated by solid phase extraction with anion exchange resin cartridge. This method was applied to the determination of cadmium in water and food with good results.